Damage

Q&A

Damage
Description

L. polyphyllus is a short-lived, perennial, leguminous herb (NOBANIS, 2015), although individuals more than 50 years old are known from New Zealand (Timmins and Mackenzie, 1995). Palmate leaves consist of several leaflets, about 1 cm wide, that are connected to long petioles and form a tuft that is 10-50 cm high (NOBANIS, 2015). Plants resprout easily when damaged (Timmins and Mackenzie, 1995). The root system is large and forms creeping rhizomes below ground that can penetrate to a depth of 30 cm (Chemel’kov‡ and Hejcman, 2012). A flowering plant can form one to several flowering stems 50-150 cm high (NOBANIS, 2015). Each flowering stem contains tens of flowers in a raceme, and flowers open sequentially from the base of the raceme (Haynes and Mesler, 1984). L. polyphyllus has three main flower colour morphs (blue, pink, and white) that vary in frequency among populations (Pohtio and TerŠs, 1995). Hairy, 5 cm long pods contain up to 10 or 12 seeds (NOBANIS, 2015) - colour and pigmentation may vary among individual plants (Aniszewski et al., 2001;S›ber and Ramula, 2013). Seed length is about 4-4.5 mm and seed weight ranges from about 10 mg up to nearly 70 mg (Aniszewski et al., 2001).

Biological Control
Fungal pathogens could potentially be used as biological control in the future because they are currently causing the deaths of adult L. polyphyllus individuals in New Zealand (Timmins and Mackenzie, 1995).

Source: cabi.org
Damage
Description

In general, the adult form has white, slightly iridescent wings with a dark brown band at the outer margin and a characteristic white spot on the forewing, in the discoidal cell (Mally and Nuss, 2010). Some individuals may have a brown anal margin in the forewing and some may be entirely brown, but still show a white forewing spot. The wingspan can reach 4 cm. Adults can reach a lifespan of up to two weeks and are good flyers. During daytime, they tend to rest on the box trees or on other surrounding plants.

Symptons

The larvae of C. perspectalis feed on the leaves of box trees but can attack the bark of the trees, causing them to dry out and die (Leuthardt and Baur, 2013). Typical symptoms include feeding damage on the leaf edges, with sometimes only leaf skeletons remaining. Attendant symptoms are webbing of the branches with frass and residues of moulting such as, black head capsules of different sizes. Heavy damage or repeated attacks lead to total defoliation of the trees, the subsequent attack of the bark causing the death of the tree.

Biological Control
The only detected parasitoids feeding on C. perspectalis in Europe are polyphagous species (Wan et al., 2014) and predation by birds is low, probably due to the high levels of toxic alkaloids sequestered by the larva (Leuthardt and Baur, 2013). Therefore, neither would be useful biological control agents. Trichogramma, pathogens and entomopathogenic nematodes are effective in the laboratory, but not yet in the field (Gšttig and Herz, 2014, Wan et al., 2014). The introduction of specific parasitoids from the area of origin should be envisaged because it represents the only long-term control option in natural habitat. Unfortunately, little is known on the natural enemies of the moth in Asia.

Source: cabi.org
Damage
Description

Leafhoppers of the subfamily Idiocerinae are predominantly found on trees and shrubs. They are characterized by a broad rounded head, extending little between the eyes, and a general 'wedge' shape. According to Viraktamath (1989), 14 idiocerine species, in three genera (Amritodus, Busoniomimus and Idioscopus), breed on mango trees and of these only six are of economic importance. Unfortunately, there is no comprehensive taxonomic treatment available to separate all the mango-associated species.

Symptons

Nymphs and adults of Idioscopus species suck phloem sap from the inflorescences and leaves. The affected florets turn brown and dry up, and fruit setting is affected. Other effects of feeding are caused by honeydew on which sooty mould develops, affecting photosynthesis. Some damage may also occur through egg laying into the leaves and flower stems.

Hosts

I. nagpurensis is only known to attack mango trees, although it is also associated with other trees, at least in Sri Lanka (Gnaneswaran et al., 2007).

Host plant resistance

Presumably because of the time needed to grow mango trees large enough to test, there have been relatively few studies devoted to varieties resistant to attack by mango leafhoppers. Murthi and Abrahim (1983) investigated 12 mango varieties for population fluctuations of the hoppers during preflowering and postflowering periods by means of monthly sweeps of trees of uniform age. Progeny production by I. niveosparsus on floral branches was positively associated with the nitrogen content of the branches. Khaire et al. (1987) screened 19 varieties under field conditions for resistance to I. clypealis. In a study of the seasonal occurrence of mango leafhoppers, including I. nagpurensis, on a number of mango cultivars and hybrids in an orchard at Dharwad, Karnataka, India, cv. Baneshan and hybrid Neelgoa showed the lowest insect incidence (Shashidhar Viraktamath et al., 1996). Cultivars Baneshan and Khader and hybrids Neelgoa and Rumani were considered potentially useful in developing further resistant cultivars and hybrids.

Biological Control
To date there have been few studies where biological control has been attempted against mango leafhoppers. Several fungal pathogens may prove useful for biological control as mentioned by Kumar et al. (1983).

Source: cabi.org
Description

Cuscuta species have a very distinct appearance, consisting mainly of leafless, glabrous, yellow or orange twining stems and tendrils, bearing inconspicuous scales in the place of leaves. In C. campestris, the yellow to pale orange true stems, about 0.3 mm in diameter, generally do not twine and attach to the host, but produce tendrils of similar appearance, arising opposite the scale leaves, which do form coils and haustoria (Dawson, 1984). The seedling has only a rudimentary root for anchorage, while the shoot circumnutates, i.e. swings round anti-clockwise about once per hour, until it makes contact with any stem or leaf, round which it will coil before growing on to make further contacts. The root and shoot below this initial attachment soon die, leaving no direct contact with the soil. Haustoria form on the inside of the coils and penetrate to the vascular bundles of susceptible hosts. Flowers, each about 2 mm across, occur in compact clusters 1-2 cm across. There is a calyx of 5 fused sepals with obtuse or somewhat acute lobes, and 5 corolla lobes, triangular, acute, often turned up at the end, equalling the length of the tube. Stamens alternate with the corolla lobes, each with a fringed scale below. The ovary is almost spherical with a pair of styles with globose tips. The capsule reaches 2-3 mm across when mature, with a depression between the two styles. The capsule does not dehisce and seeds remain on the plant long after maturity. Seeds are irregular in shape, rough-surfaced, about 1 mm across.

Symptons


The presence of Cuscuta is always obvious from the twining stems and tendrils. Symptoms of damage are not especially characteristic, but reflect the very powerful sink effect created by the haustoria, resulting in reduced vigour and, in particular, poor seed and fruit development.

Impact


The parasitic weed C. campestris is native to North America but has been introduced around the world and become a weed in many countries. It is by far the most important of the dodders, perhaps because of its wide host range. This ensures that there is a wide range of crop seeds that may be contaminated, and in which it may be introduced to new areas over both short and long distances. Once introduced it is almost certain that there will be suitable host plants on which it can thrive and be damaging, whether they are crops or wild species. Vegetative spread can be very rapid – up to 5 m in 2 months. It also has a wide tolerance of climatic conditions from warm temperate to sub-tropical and tropical.

Hosts


The host range of C. campestris is extremely wide. Several hundred crop and weed species have been listed as hosts, though some of these may only be acting as secondary hosts after the parasite is established on a more favoured primary host (e.g. Gaertner, 1950;Kuijt, 1969). Most are dicotyledonous, though the monocot onion can be seriously attacked. The plant is most important as a pest of lucerne and other legumes. Grasses sometimes appear to be acting as hosts but are not normally penetrated. The literature on host range is usefully reviewed by Cooke and Black (1987). Crops commonly parasitized, other than those listed in the table, include asparagus, chickpea, lentil, grape, citrus, melon, Lespedeza and flower crops including chrysanthemum. Not all hosts are consistently attacked, for example tomato is susceptible when young but becomes resistant with age (Gaertner, 1950).


Source: cabi.org
Description


Eggs
The eggs of G. rostochiensis are always retained within the cyst body and no egg sacs are produced. The eggshell surface is smooth and no microvilli are present.
Length=101-104 µm;width="46"-48 µm;L/W ratio=2.1-2.5
Females
The females emerge from the root cortex about one month to six weeks after invasion by the second-stage juveniles. They are pure white initially, turning golden yellow on maturation. Mature females are approximately 500 µm in circumference without a cone. The cuticle of the female sometimes has a thin subcrystalline layer.
Stylet length=23 µm ± 1 µm;stylet base to dorsal oesophageal gland duct=6 µm ± 1 µm;head width at the base=5.2 µm ± 0.7 µm;head tip to median bulb=73 µm ± 14.6 µm;median bulb valve to excretory pore=65 µm ± 2.0 µm;head tip to excretory pore=145 µm ± 17 µm;mean diameter of the median bulb=30µm ± 3.0 µm;mean diameter of the vulval basin=22 µm ± 2.8 µm;vulval slit length=9.7 µm ± 2.0 µm;anus to vulval basin=60 µm ± 10 µm;number of cuticular ridges between the anus and vulva=21 ± 3.0.
The female head bears one to two annules and the neck region has numerous tubercules, which can be seen using a scanning electron microscope. The head skeleton is hexaradiate and weak. The stylet is divided equally in length between the conus and the shaft. An important diagnostic feature is the backward slope of the stylet knobs. The median bulb is large and circular and well developed. The large paired ovaries often displace the oesophageal glands. The excretory pore is well defined at the base of the neck. The posterior of the female, at the opposite pole to the neck and head, is referred to as the vulval basin and is contained within a rounded depression. The vulval slit is located in the centre of this region flanked on either side by papillae, which usually fill the translucent areas of cuticle in crescentic shape, from the slit to the edge of the fenestra. The anus is distinct and is often seen at the point in the cuticle where the 'V' shape tapers to an end. The number of cuticular ridges found in the area between the anus and the edge of the fenestra is counted as an aid to identification of Globodera species. The entire cuticle is covered in small subsurface punctations.
Cyst
Length without neck=445 µm ± 50 µm;width="382" µm ± 60 µm;neck length=104 µm ± 19 µm;mean fenestral diameter=19.0 µm ± 2.0 µm;anus to fenestra=66.5 µm ± 10.3 µm;Granek's ratio=3.6 ± 0.8.
Cysts contain the eggs, the progeny for the next generation, and are formed from the hardened dead cuticle of the female. Newly produced cysts may still show an intact vulval basin but older cysts, particularly those which have been in the soil for many seasons, will have lost all signs of their genitalia with only a hole in the cuticle to show the position of the fenestral basin.
Males
Length=0.89 -1.27 mm;width at excretory pore=28 µm ± 1.7 µm;head width at base=11.8 µm ± 0.6 µm;head length=7.0 µm ± 0.3 µm;stylet length=26 µm ± 1.0 µm;stylet base to dorsal oesophageal gland duct=5.3 µm ± 1.0 µm;head tip to median bulb valve=98.5 µm ± 7.4 µm;median bulb valve to excretory pore=74 µm ± 9µm;head tip to excretory pore=172 µm ± 12.0 µm;tail length=5.4 µm ± 1.0 µm;tail width at anus=13.5 µm ± 0.4 µm;spicule length=35.0 µm ± 3.0 µm;gubernaculum length=10.3 µm ± 1.5µm.
The male is vermiform in shape with a short tail and no bursa. On fixation, the body assumes a curved shape with the posterior region twisted at a 90 degree angle to the remainder of the body. There are four incisures in the mid-body i.e. three bands which terminate on the tail. The rounded head is offset and bears 6-7 annules. The head is strongly developed having a hexaradiate skeleton. The cephalids are located at body annules 2-4 and 6-9, respectively. The stylet is strong and has backward sloping knobs. The median bulb is well developed and has a large crescentic valve. The nerve ring is located around the oesophagus between the median bulb and the intestine. The hemizonid is found 2-3 annules anterior to the excretory pore and is itself two annules in length. The hemizonion is approximately nine body annules posterior to the excretory pore and is one annule in length. The single testis fills half the body cavity. The paired spicules are arcuate and end with single tips. The gubernaculum is around 10 µm in length and 2 µm in thickness and lies in a position dorsal to the spicules.
Juveniles
Body length=468 µm ± 100 µm;width at excretory pore=18 µm ± 0.6 µm;head length=4.6µm ± 0.6 µm;stylet length=22 µm ± 0.7 µm;head tip to median bulb valve=69 µm ± 2.0 µm;median bulb valve to excretory pore=31 µm ± 2.0 µm;head tip to excretory pore=100 µm ± 2.0 µm;tail length=44 µm ± 12 µm;tail width at anus=11.4 µm ± 0.6 µm;hyaline tail length=26.5 µm ± 2.0 µm.
The second-stage juvenile hatches from the egg, the first moult taking place within the egg. The juvenile, like the male, is vermiform with a rounded head and finely tapered tail. The hyaline portion of the tail represents about two thirds of its length. The lateral field has four incisures in the mid-body region reducing to three at the tail terminus and anterior end. The head is slightly offset and bears four to six annules. The head skeleton is well developed and hexaradiate in form. The cephalids are located at body annules 2-3 and 6-8, respectively. The stylet is strong, the conus being about 45% of the total length. The stylet knobs are an important diagnostic feature and typically slope backwards. The median bulb is well developed and elliptical in shape, having a large central valve. The nerve ring encircles the oesophagus between the median valve and the intestine. The hemizonion is about one body annule in width and is located five body annules posterior from the excretory pore. The hemizonid is around two body annules in width and is found just anterior to the excretory pore. The gonad primordium is four-celled and located at around 60% of the body length.
Other measurements can be found in Granek (1955), Spears (1968), Green (1971), Greet (1972), Golden and Ellington (1972), Hesling (1973, 1974), Mulvey (1973), Behrens (1975), Mulvey and Golden (1983), Othman et al. (1988) and Baldwin and Mundo-Ocampo (1991).

Recognition


Potato cyst nematodes, in common with other cyst nematodes, do not cause specific symptoms of infestation. Initially, crops will display patches of poor growth and these plants may show chlorosis and wilting. When the tubers are harvested there will be a yield loss and tubers will be smaller. To be confident that these symptoms are caused by potato cyst nematodes and to give an indication of population density, soil samples must be taken or the females or cysts must be observed directly on the host roots. Detection based on host plant symptoms and identification by morphological and molecular methods are detailed in EPPO (2009).
Surveys of the numbers and distribution of potato cyst nematode are prerequisites for making informed choices for their management. Samples taken within a field are either to check whether potato cyst nematode is present or not in the field for statutory purposes or to determine the extent of the infestation, which might include a determination as to what species is present.
At one time, it was considered that nematodes had a haphazard distribution in the field but this has been disproved. Aspects of the environment and ecological factors such as disease, predators and soil type favour aggregated distributions. Many models help to describe distributions, for example Taylor's Power Law (Taylor, 1961), Iwao's regression model (Allsopp, 1990) and others. However, geostatistical techniques may provide a more purposeful definition of the spatial distribution of nematodes. Although these techniques are young, 3-D maps can be generated to study nematode population levels more effectively. These methods have already proved useful in mapping other types of field related data (Chellemi et al., 1988) and have recently been applied to the distribution of potato cyst nematodes (Evans et al., 2003).

Symptons


Potato cyst nematodes, in common with other cyst nematodes, do not cause specific symptoms of infestation. Initially, crops will display patches of poor growth and plants in these patches may show chlorosis and wilting. When the tubers are harvested there will be a yield loss and tubers will be smaller. To be confident that these symptoms are caused by potato cyst nematodes and to give an indication of population density, soil samples must be taken or the females or cysts must be observed directly on the host roots. In heavily infested soils, plants have reduced root systems and often grow poorly due to nutrient deficiencies and to water stress. Plants may senesce prematurely as they are more susceptible to infection by fungi such as Verticillium spp. when heavily invaded by potato cyst nematodes.
Direct damage to roots and the yield of tubers
The infective second stage juveniles of both G. rostochiensis and G. pallida respond to environmental conditions when hatching. There is a short period of time for the second stage juvenile to locate a host root and begin the process of invasion, usually just behind the root tip. The juveniles then position themselves next to the stele within the root where, after a few hours, they will establish a feeding site (syncytium), which will become their nutrient source until their death. If a susceptible variety of potato is planted the plants will soon show signs of attack particularly when nematode density is high. In resistant plant varieties juveniles still hatch from the cyst and invade the plant roots, but they are unable successfully to establish a feeding site or syncytium. In this situation, males are more likely to be produced than females, as males have negligible nutrient requirements compared to females. Nevertheless, even resistant crops may show signs of attack.
The reduction in the yield of potato tubers, depending on the cultivar grown, is also related to or dependent on the plant's ability to tolerate the effects of nematode attack. The effects of potato cyst nematode on the plant include water stress and early senescence of the leaves. A heavily infested plant is unlikely to produce 100% ground cover with its reduced canopy of leaves. Many field studies have monitored the progression of ground cover by leaves and correlated the findings with yields (see Trudgill et al., 1998).

Impact

G. rostochiensis is a world wide pest of temperate areas, including both temperate countries and temperate regions of tropical countries, for example India’s Nigrilis region. Distribution is linked to that of the potato crop. Potato cyst nematode is considered to have originated from the Andes region of South America, from where it spread to Europe with potatoes. The ease with which it has been transported across continents proves what a resilient pest it is. The cyst form which adheres to host roots, stolons and tubers and to soil particles during transportation gives rise to new infestations where climate and food source are both available and favourable.

Hosts


The major hosts of G. rostochiensis are restricted to the Solanaceae, in particular potato, tomato and aubergine (Ellenby, 1945, 1954;Mai, 1951, 1952;Winslow, 1954;Stelter, 1957, 1959, 1987;Roberts and Stone, 1981;Sullivan et al., 2007). A number of weeds in the Solanaceae are also hosts.
In addition to the main hosts listed, the following plants are hosts of G. rostochiensis:
Datura tatula, D. ferox, Hyoscyamus niger, Lycopersicon aureum, L. glandulosum, L. hirsutum, L. esculentum peruvianum, L. pimpinellifolium, L. pyriforme, L. racemigerum, Nicotiana acuminata, Physalis longifolia, P. philadelphica, Physochlaina orientalis, Salpiglossis sp., Saracha jaltomata, Solanum acaule, S. aethiopicum, S. ajanhuiri, S. ajuscoense, S. alandiae, S. alatum, S.americanum, S. anomalocalyx, S. antipoviczii, S. armatum, S. ascasabii, S. auriculatum, S. asperum, S. aviculare, S. berthaultii, S. blodgettii, S. boergeri, S. brevidens, S. brevimucronatum, S. bukasovii, S. bulbocastanum, S. calcense, S. calcense × S. cardenasii, S. caldasii, S. canasense, S. capsicibaccatum, S. capsicoides, S. cardiophyllum, S. carolinense, S. chacoense, S. chaucha, S. chenopodioides, S. chloropetalum, S. citrillifolium, S. coeruleiflorum, S. commersonii, S. curtilobum, S. curtipes, S. demissum, S. demissum × S. tuberosum, S. dulcamara, S. durum, S. elaeagnifolium, S. ehrenbergii, S. famatinae, S. fraxinifolium, S. fructo-tecto, S. garciae, S. gibberulosum, S. giganteum, S. gigantophyllum, S. gilo, S. glaucophyllum, S. goniocalyx, S. gourlayi, S. gracile, S. heterophyllum, S. heterodoxum, S. hirtum, S. hispidum, S. indicum, S. integrifolium, S. intrusum, S. jamesii, S. jujuyense, S. juzepczukii, S. kesselbrenneri, S. kurtzianum, S. lanciforme, S. lapazense, S. lechnoviczii, S. leptostygma, S. ligustrinum, S. longipedicellatum, S. luteum, S. macolae, S. macrocarpon, S. maglia, S. malinchense, S. mamilliferum, S. marginatum, S. mauritianum, S. melongena, S. miniatum, S. mochiquense, S. multidissectum, S. muricatum, S. neocardenasii, S. nigrum, S. nitidibaccatum, S. ochroleucum, S. okadae, S. oplocense, S. ottonis, S. pampasense, S. parodii, S. penelli, S. photeinocarpum, S. phureja, S. pinnatum, S. pinnatisectum, S. platense, S. platypterum, S. polyacanthos, S. polyadenium, S. prinophyllum, S. quitoense, S. radicans, S. raphanifolium, S. rostratum, S. rybinii S. salamanii, S. saltense, S. sambucinum, S. sanctae-rosae, S. sarrachoides, S. scabrum, S. schenkii, S. schickii, S. semidemissum, S. simplicifolium, S. sinaicum, S. sisymbrifolium, S. sodomaeum, S. soukupii, S. sparsipilum, S. spegazzinii, S. stenotomum, S. stoloniferum, S. suaveolens, S. subandigenum, S. sucrense, S. tarijense, S.tenuifilamentum, S. tlaxcalense, S. tomentosum, S. toralopanum, S. triflorum, S. tuberosum ssp. andigena, S. tuberosum ssp. tuberosum, S. tuberosum 'Aquila', S. tuberosum 'Xenia N', S. utile, S. vallis-mexicae, S. vernei, S. verrucosum, S. villosum, S. violaceimarmoratum, S. wittmackii, S. wittonense, S. xanti, S. yabari and S. zuccagnianum.
Note Oxalis tuberose (Oca), has been extensively tested in host range tests by Sullivan et al. (2007) and has been declared a non-host on this basis.


Source: cabi.org
Description

X. fastidiosa is a fastidious Gram-negative, xylem-limited bacterium, rod-shaped with rippled cell walls. It is strictly aerobic (microaerophilic), non-flagellate, does not form spores and measures 0.1-0.5 x 1-5 µm. The peach strain was given by Nyland et al. (1973) as 0.35 x 2.3 µm. See also Bradbury (1991). Thread-like strands (fimbriae) attached to the polar ends of bacterial cells can be observed in electron microscopy (Mircetich et al., 1976) and scanning electron microscopy (Feil et al., 2003b). These probably function in bacterial attachment and 'twitching' movement (Meng et al., 2005).

Recognition


Symptoms are not reliable for detection of infected plants in transit.
X. fastidiosa can be detected microscopically (light or electron) in vessels in cross-sections of petioles (French et al., 1977) or by examining xylem sap squeezed from symptomatic stems or petioles or flushed from stems or petioles onto microscope slides (De Lima et al., 1998). Flushing of xylem sap from shoots with a pressure chamber allows the testing of larger sample sizes and avoids inhibitors for PCR (Bextine and Miller, 2004). Methods such as grafting to susceptible indicator plants or vector tests (Hutchins et al., 1953) are still available, and may have their place in certification schemes in which woody indicators are routinely used. X. fastidiosa can also be isolated onto suitable selective media (Davis et al., 1978, 1983;Raju et al., 1982;Wells et al., 1983). The identity of cultured bacteria can be confirmed by SDS-PAGE (Bazzi et al., 1994). Serological methods are less sensitive (10- to 100-fold) than culture but are the easiest means of detecting and identifying the bacterium, by ELISA or use of fluorescent antibodies (French et al., 1978;Walter, 1987;Hopkins and Adlerz, 1988;Sherald and Lei, 1991). Strains differ in quantitative reaction to antisera and in ease and efficiency of culture. DNA hybridization probes and PCR primers specific to X. fastidiosa have been developed (Firrao and Bazzi, 1994;Minsavage et al., 1994). X. fastidiosa can also be detected in its insect vectors (Yonce and Chang, 1987). The characterization and identification of strains chiefly employs molecular genetic methods (e.g., Chen et al., 1992;Hendson et al., 2001;Coletta-Filho et al., 2003), and can be expected to remain indefinitely in a state of change.
Different diagnostic methods used or developed for the detection and identification of X. fastidiosa are detailed in Janse (2009). Recent advances in detection include on-site molecular detection using real-time loop-mediated isothermal amplification (Yaseen et al., 2015).

Symptons

On grapevines
The most characteristic symptom of primary infection is leaf scorch. An early sign is sudden drying of part of a green leaf, which then turns brown while adjacent tissues turn yellow or red. The desiccation spreads and the whole leaf may shrivel and drop, leaving only the petiole attached. Diseased stems often mature irregularly, with patches of brown and green tissue. In later years, infected plants develop late and produce stunted chlorotic shoots. Chronically infected plants may have small, distorted leaves with interveinal chlorosis and shoots with shortened internodes. Highly susceptible cultivars rarely survive more than 2-3 years, despite any signs of recovery early in the second growing season. Young vines succumb more quickly than do older vines. More tolerant cultivars may survive chronic infection for more than 5 years (Hewitt et al., 1942;Goodwin and Purcell, 1992).
On peaches
Young shoots are stunted and bear greener, denser foliage (due to shorter internodes) than healthy trees. Lateral branches grow horizontally or droop, so that the tree seems uniform, compact and rounded. Leaves and flowers appear early, and leaves remain on the tree longer than on healthy trees. Affected trees yield increasingly fewer and smaller fruits until, after 3-5 years, they become economically worthless (Hutchins, 1933).
On citrus
Trees can start showing the symptoms of variegated chlorosis from nursery size up to more than 10 years of age. Younger trees (1-3 years) become systemically colonized by X. fastidiosa much faster than do older trees. Trees more than 8-10 years old are not usually totally affected, but rather have symptoms on the extremities of branches. Affected trees show foliar chlorosis resembling zinc deficiency with interveinal chlorosis. The chlorosis appears on young leaves as they mature and may also occur on older leaves. Newly affected trees show sectoring of symptoms, whereas trees which have been affected for a period of time show the variegated chlorosis throughout the canopy. As the leaves mature, small, light-brown, slightly raised gummy lesions (becoming dark-brown or even necrotic) appear on the underside, directly opposite the yellow chlorotic areas on the upper side.
Fruit size is greatly reduced;it may take 550 affected fruits to fill a field box, compared with 250 normal fruits. The sugar content of affected fruit is higher than in non-affected fruit, and the fruit has a hard rind, causing damage to juicing machines. Blossom and fruit set occur at the same time on healthy and affected trees, but normal fruit thinning does not occur on affected trees and the fruits remain small but open earlier. Since more fruits remain, total production is not greatly reduced. On affected trees of cv. Pera and other orange cultivars, fruits often occur in clusters of 4-10, resembling grape clusters. Affected trees show stunting and slow growth rate;twigs and branches die back and the canopy thins, but affected trees do not die (Chang et al., 1993a,b;Lee et al., 1991, 1993).
Control has been achieved by removing inoculum in established orange groves and using sanitary measures to prevent infection of nurseries and new groves. All symptomatic branches from trees older than 3 years are cut off up to 1 m below the most basal symptoms. Symptomatic trees less than 4 years old are removed. To prevent the infection of nursery trees, nurseries are located away from citrus plantings, sharpshooters are controlled prophylactically by insecticides, and buds are taken from trees tested free of X. fastidiosa and grown vectors in screen houses or glass houses to exclude vectors. The effectiveness of these measures (Rodas, 1994) indicates that most spread of variegated chlorosis is from tree to tree within citrus orchards (Laranjeira, 1997).
On olives
On olives, quick decline syndrome is characterised by the development of leaf scorch symptoms and desiccation of small twigs and branches. Symptoms generally initiate in the upper part of the canopy on one or two branches, and then extend to the remainder of the crown. Severely affected plants are often pruned heavily, favouring spindly new growth which also succumbs to scorch symptoms. The tree may send out suckers from the base of the plant which subsequently die back, until the root system dies entirely (Martelli, 2016a). Grafting experiments have demonstrated that it takes at least 7 months for leaf scorch symptoms to appear on the grafted plant part (European Food Safety Authority, 2015).
Symptoms are found on all known varieties of olive. Older varieties, such as Ogliarola Salentina, Cellina di Nardò and common varieties Frantoio and Coratina, appear susceptible. It is suggested that the variety Leccino seems less susceptible, although records are based on field observations and are yet to be experimentally confirmed. Apparent variation in olive varietal susceptibility may be the result of differences in disease vector pressures in the areas where the disease is present (European Food Safety Authority, 2015).
Vectors
Vector feeding causes no visible damage. Xylem feeders are prodigious feeders, consuming hundreds of times their body volumes per day in xylem sap. Most non-xylem-feeding leafhoppers produce a sugary or particulate excrement, but that of xylem feeders is watery, drying to a fine whitish powder (brochosomes) where abundant (Rakitov, 2004). The excrement of froghopper nymphs takes the form of persistent bubbles or 'froth;that surrounds the body of the insect, presumably to provide protection from natural enemies.

Hosts

No grapevine (Vitis spp.) species are known to be immune to Pierce’s disease strains of X. fastidiosa, but American species used as rootstocks (V. aestivalis, V. berlandieri, V. candicans, V. rupestris) and hybrids derived from them are tolerant and some may be resistant, as is V. rotundifolia (Goheen and Hopkins, 1988). Almonds and lucerne can be hosts of the grapevine strains, but the diseases caused by X. fastidiosa in these three crop species are independent within California, USA, suggesting as yet unidentified biological differences (Purcell, 1980b). A very high percentage (75% of those tested) of crop, wild plant and weed species can carry Pierce’s disease strains of the bacterium without symptoms (e.g. wild grasses, sedges, lilies, various bushes and trees) (Raju et al., 1983;Hopkins and Adlerz, 1988;Hill and Purcell, 1995b). It is likely that in most symptomless host species, X. fastidiosa multiplies to lower populations and moves systemically less often than in pathological hosts. For example, blackberry (Rubus spp.) can be a systemic host, but the bacterium multiplies in mugwort (Artemisia douglasiana) without systemic movement (Hill and Purcell, 1995b). Hosts can be classified as propagative or non-propagative, systemic or non-systemic, and symptomatic or non-symptomatic (Purcell and Saunders, 1999b). Propagative, systemic hosts are the best hosts for efficient vector acquisition of bacteria, but vectors can acquire the bacterium from non-systemic hosts. Acquisition efficiency is proportional to the populations of live bacterial cells within plant tissues (Hill and Purcell, 1997).
Peach (Prunus persica) strains of X. fastidiosa cause peach phony disease (Wells et al., 1983), which also attacks Prunus salicina (causing leaf scald). All cultivars, forms and hybrids of peach are attacked, whether on their own roots or other rootstocks. Plums (Prunus domestica), almonds (P. dulcis), apricots (P. armeniaca) and the wild P. angustifolia were reported susceptible to phony disease before the association with X. fastidiosa was established. This reported range partly overlaps that of the grapevine-infecting strains. Various perennial weeds of orchards, such as Sorghum halepense, may act as reservoirs for the peach-infecting strain (Yonce, 1983;Yonce and Chang, 1987), but the plant host range of Prunus strains from the south-eastern USA has not been investigated extensively. Pierce's disease strains also cause almond leaf scorch disease (Davis et al., 1980), but the almond strains infect grape in low populations and without causing disease (Almeida and Purcell, 2003).
X. fastidiosa in the wide sense also causes leaf scorch in Acer rubrum (Sherald et al., 1987), Morus rubra (Kostka et al., 1986), Platanus occidentalis (Sherald, 1993a,b) (wilt and leaf scorch), Quercus rubra (Chang and Walker, 1988), Ulmus americana and Vinca minor (stunt). Strains from Ulmus and from P. occidentalis are not reciprocally infectious (Sherald, 1993a). The bacteria involved are not known to be transmissible to grapevine. Diseases of numerous woody ornamental plants in southern California, USA, including olive, date palm and rosemary, have been associated with X. fastidiosa but a causal relationship is still unproven (Wong and Cooksey, 2004). Until their relationships and pest significance have been clarified, they can all be regarded as potentially dangerous for Europe and the Mediterranean region.
X. fastidiosa causes citrus variegated chlorosis in Brazil (Lee et al., 1991;Chang et al., 1993;Hartung et al., 1994) and Argentina (Brlanksy et al., 1993). The disease affects mostly sweet oranges (Citrus sinensis);it has been observed especially on cultivars Pera, Hamlin, Natal and Valencia. It occurs on trees propagated on all commonly used rootstocks in Brazil: C. limonia, C. reshni and C. volkameriana. The disease has not been observed on C. latifolia or mandarins (C. reticulata), even when the trees were planted in severely affected orange groves (Li et al., 2000). The effectiveness of removing diseased citrus trees to prevent further spread of variegated chlorosis in citrus (Rodas, 1994) strongly suggests that most spread of this disease is from tree to tree within the crop. Control measures require the production of disease-free nursery trees in protected environments.
Citrus blight in Florida, USA, has been associated with X. fastidiosa (Adlerz et al., 1989;Hopkins et al., 1996);however the preponderance of evidence suggests that it is not the cause of blight (Derrick and Timmer, 2000).
Plum leaf scald is an important crop-limiting disease caused by X. fastidiosa from Brazil through Argentina. The South American plum leaf scald strains appear to differ from those in North America, as there are no reports of phony disease of peach in South America. The plum leaf scald strains in Brazil may have wide plant host ranges (Leite et al., 1997). A leaf scorching disease of coffee (De Lima et al., 1998) is caused by strains of X. fastidiosa that appear to be closely related to the citrus variegated chlorosis strains (Rosato et al., 1998), but its ability to cause disease in citrus (Li et al., 2001) is controversial.
In Europe and the Mediterranean region, grapevine and citrus are clearly the most significant potential crop hosts, although peach and plum are also important. Strains that cause leaf scorch diseases in oak, elm, sycamore (plane) (Hearon et al., 1980), mulberry (Kostka et al., 1986) and other tree species are also potentially damaging. Many other hosts could carry the bacterium, without necessarily being significantly affected.
X. fastidiosa has been implicated as the causal agent of olive quick decline syndrome in Europe. In 2013, X. fastidiosa subsp. pauca was associated with quick decline syndrome on olive, almond and oleander in Europe (southern Italy, Apulia region) (European Food Safety Authority, 2015). Symptomatic olive trees were often affected by multiple pests, including X. fastidiosa, several fungal species, and Zeuzera pyrina (leopard moth) (Nigro et al., 2013). Recent experimental evidence (Saponari et al., 2016) has confirmed X. fastidiosa as the causal agent of olive quick decline syndrome in Italy (European Food Safety Authority, 2016). In the USA a study evaluating olive as a host for X. fastidiosa concluded that subsp. multiplex was present but was not the cause of the leaf scorch and dieback symptoms observed on olive trees in California (Krugner et al., 2014). However, X. fastidiosa subsp. pauca has been implicated as a causal agent of olive plant dieback and leaf desiccation in Argentina (Haelterman et al., 2015). More recently, leaf scorch symptoms on olive trees in Brazil have been associated with X. fastidiosa subsp. pauca (Coletta-Filho et al., 2016).
The host range of X. fastidiosa based on the available peer-reviewed literature is presented in European Food Safety Authority (2015).
According to the European Food Safety Authority (2016), the current list of host plant species for X. fastidiosa consists of 359 plant species (including hybrids) from 204 genera and 75 different botanical families.


Source: cabi.org
Title: Limax maximus
Description

Slug Ð animal without an external shell. Large, with a saddle-like mantle shield that overs only the anterior part of the body, containing a vestigial shell as an oval plate. Mantle covered with black spots and mottles, back with black mottles and broken bands. Pneumostome or breathing pore (the opening to the lung) Ð in right posterior margin of mantle shield.;Species described in detail by Quick (1949, 1960), Wiktor (1973, 1983, 1996), Likharev and Wiktor (1980), Barker (1999), and many other authors. See Barker (1999) for terminologies.;Adults

Symptons

Damage is simply holes rasped in plant tissues. While mollusc damage is characteristic to the expert, it resembles that caused by various insects with which it is often confused.;The damage caused to plants by L. maximus is not readily differentiated from that caused by other gastropods. Even the association of L. maximus with damaged plants is not definitive evidence that the species is solely or even partially responsible.

Hosts

L. maximus will feed on living plants and is capable of inflicting significant damage to garden plants. Theobald (1895) listed L. maximus as one of the three most destructive species of slug in Britain (along with Deroceras reticulatum [as Limax agreste ], and Arion ater), without any justification. Taylor (1902-07) did not cite L. maximus as a pest, although he stated that it would eat young garden plants (but preferred fungi). White (1918) considered L. maximus a major pest of cultivated plants and mushrooms. For the most part the recognition of L. maximus as a pest of cultivated plants and cultivated mushrooms has diminished since the early 20 th Century, in large part because it has become widely appreciated that other slug species (e.g. Deroceras reticulatum, Arion hortensis) are more pestiferous and the predominant cause of damage in the garden. Due to its large size, L. maximus is often a conspicuous member of the garden fauna and thus often erroneously assumed to be responsible for any damage observed.;There have been no quantitative studies that determine the relative contributions of L. maximus to plant losses occurring in gardens due to slugs. Nonetheless, some authors continue to mention L. maximus as a serious garden pest (e.g. Pirone, 1978, Stange, 1978, Ebeling, 2002, Kozlowski, 2012a,b, Texas Invasive Species Institute, 2004).;The greatest potential for plant damage by L. maximus in the agricultural sector is in protected cropping, such as in glasshouses and greenhouses, or where crops occur near other dense vegetation, as the high moisture conditions and availability of daylight resting sites are highly favourable to high densities and activity. Nonetheless, there are no quantitative data available to implicate L. maximus as a significant pest in these cropping situations.;In arable fields L. maximus rarely occurs at densities sufficient to present risk to crops.;Numerous cultivated plants have been recorded as being damaged by L. maximus, but the literature is clearly not comprehensive. The significance of L. maximus as a pest in commercial mushroom beds has greatly diminished with modern mushroom cultivation practices.;In non-agricultural areas, L. maximus feeds on a variety of plants (e.g. on Coincya monensis, Hipkin and Facey, 2009) and may cause plant mortality, especially in the seedling stage. For the most part this herbivory by L. maximus goes unnoticed in these situations and there is very little published information on its ecosystem-level significance. However, recent experimental work has shown that L. maximus makes a significant contribution to herbivory on seedlings in higher elevation, subtropical to temperate rainforests in Hawaii (Joe, 2006, Joe and Daehler, 2008) and in boreal forests in North America (Noel, 2004, Holloway 2008, Humber, 2009, Moss and Hermanutz, 2009, 2010, Gosse et al., 2011) which may have implications for plant recruitment in both forest systems.;It is also recognized that L. maximus feeds extensively on fungi, especially fungal fruiting structures, in woodland and forest systems (Elliott, 1922, Fršmming, 1940, Keller and Snell, 2002, Halbwachs and BŠssler, 2015). However, the ecosystem-level significance of this mycophagy is unknown.


Source: cabi.org
Title: Limax maximus
Description

D. invadens is a small, agile, slug species with a reputation for pugnacity towards other slugs. Size range is 25-35 mm. The body is cylindrical, narrowing to a short but strongly truncate keel at the tail. The mantle is moderately large but less so proportionately than in D. laeve, so that the tail part of the body is clearly longer than the mantle. In living specimens the mantle is transversely wrinkled in front as in D. laeve. The body colour is variable. In Mediterranean countries a pinkish flesh-coloured ground colour is common with a translucent cuticle and few if any darker spots. This form can also occur in northern Europe. In north-west Europe two forms predominate, these are slightly or considerably darker colour forms. The most common is mid gray and translucent with lighter mantle, through the cuticle of which the shell and pale internal organs can be seen even in the field. There is a marbling of tiny darker spots, but these are difficult to see with the naked eye. In hilly or exposed areas a darker form occurs, with mid to dark grey ground colour and contrasting pale mantle on which darker spotting is particularly obvious. The respiratory pore is white-rimmed, more clearly marked in darkly pigmented specimens. The sole in most specimens is translucent grey and paler than upper body pigments. Pedal and body mucus is colourless. Internally D. invadens has a rounded, compact penis with two fairly symmetrical, slightly elongate and inturned, ‘side pockets’ comprising the penial caecum and penial lobe (see Reise et al., 2011).

Impact

D. invadens is a small, agile slug that is native to the Mediterranean and has been recorded from at least 46 countries worldwide. Until 2011, this species was known as D. panormitanum but molecular work revealed that it comprised two distinct species. This species is similar in appearance to D. laeve and as a result, the exact distribution and impact of this species is unknown. This is a particular problem in countries such as the USA and Australia and probably also in South America. D. invadens is regarded as a significant pest of agricultural crops in New Zealand (Barker, 1999) but is highly likely to be damaging in many other countries as well. References to slug damage in agricultural crops by D. laeve are very likely to refer to D. invadens. In addition to this, D. invadens is an aggressive slug which may compete with native slugs, decreasing biodiversity.

Hosts

D. invadens is a generalist slug and has been recorded causing agricultural damage to crops. Examples of these species include;Asparagus officinalis, Avena sativa, Brassica napus, B. oleracea, B. rapa, Cucurbita maxima, C. pepo, Daucus carota, Franaria vesca, Hordeum vulgare, Lactuca sativa, Solanum tuberosum, Triticum aestivum and T. durum.

Biological Control
Phasmarhabditis hermaphrodita is a nematode parasite of slugs which, though most effective in controlling D. reticulatum and may also kill D. invadens (Speiser et al., 2001). However, this form of control is uneconomic for field crops at present.

Source: cabi.org
Description

C. juncea is a thin, spindly, herbaceous perennial. In addition to a deep (2 m) taproot, it has lateral roots that produce daughter rosettes. Plants also grow from buds on root fragments cut by cultivation or other equipment. It has a basal rosette of dandelion-like leaves, up to 20 cm long, glabrous. They are rush-like in appearance, up to 150 cm bright green or yellow-green with multiple, slender, leafless branches and reddish downward-pointing hairs near the base. Rosette and stem leaves are deciduous. Flowers 1-2 cm across have yellow, daisy-like capitulae, borne singly or in small clusters, almost sessile on the virtually leafless stem. Fruits are achenes, white to dark, 3-4 mm long, with pappus of white toothed bristles 5-8 mm long on a beak of similar length. The leaves, stems and roots exude milky latex when damaged (Parsons and Cuthbertson, 1992).

Impact

C. juncea is a herbaceous biennial or perennial plant native to parts of Western Europe, north Africa and central Asia. It was accidentally introduced into a number of regions around the world as a contaminant of plant material, seed and fodder. C. juncea is invasive in Australia, Argentina, Canada, New Zealand, South Africa and a number of states in the USA. C. juncea produces a large tap root which can compete with native plant species for nutrients and water. In Australia and Argentina it is a major problem of wheat fields and can reduce yields by 80%. In the USA, C. juncea is one of the invasive species impacting on the threatened species Silene spaldingii. A number of distinct genotypes of C. juncea exist which makes control of this species difficult. In addition to this, C. juncea is resistant to a large number of herbicides.

Hosts

In Australia and Argentina, C. juncea is a major problem of wheat fields and can reduce yields by 80%.

Biological Control
<br>A number of biological control agents have been studied for control of C. juncea in Australia and USA. Studies were initiated by CSIRO in the 1960s and to date, a total of four biocontrol agents have been trialled with variable success.<br>A blister-forming gall midge, Cystiphora schmidti, can feed on the rosettes, stem leaves and stems, causing damage and reduction in seed production. It was first released in California in 1975 and is available for collection in California, Idaho and Oregon (USDA-NRCS, 2015).<br>The gall-forming mite, Aceria chondrillae, can infest vegetative and floral buds creating galls which if severe, can stunt the growth of the plant and reduce seed production. It is the most effective agent in the Pacific Northwest (Van Vleet and Coombs, 2012).<br>A root moth, Bradyrrhoa gilveolella, was released in Argentina and Australia but was not successful. This agent was most recently introduced in Idaho, USA in 2002 but establishment has not been confirmed (Horner, 2002).<br>A rust fungus, Puccina chondrillina, was researched as a potential biological control agent for C. juncea by Hasan and Wapshere (1973) and was first released in North America in 1978. As a result of extreme host-specificity of this rust fungus, one of the three genotypes in the USA and two in Australia are not controlled and very little control has been recorded in Argentina (Gaskin et al., 2013). Although it was the most successful agent released in Australia, the two rust-resistant genotype of C. juncea have since expanded their range to replace the rust-susceptible genotype (Gaskin et al., 2013).<br>The effectiveness of a biocontrol agent is dependent on factors such as climate, the genotype of C. juncea and interactions with native parasites and predators.

Source: cabi.org
Description

T. domingensis is a rhizomatous perennial emergent wetland macrophyte. Ramets (culms) range from 1-6 m tall (Denny, 1985b) and consist of numerous slender, linear, distichous leaves with a sheathing base that emerge vertically from a central meristem. Ramets often produce a single, erect, monoecious flowering stem consisting of a staminate spike above a pistillate spike. At maturity, ramets can collapse from wind, or under their own weight (S Hall, University of Wisconsin, USA, personal communication, 2008). Rhizomes often measure several centimeters in diameter and produce abundant adventitious roots. Smith (1967, 2000) distinguished T. domingensis from similar species primarily on the basis of pistillate spike characters. T. domingensis is characterized by: pistillate bracteoles pale to light brown, slightly exceeding pistil hairs in mature spikes;pistil hair apices colorless to orange;stigmas linear to lanceolate, slightly exceeding bracteoles in mature spikes;pistillate spikes at anthesis cinnamon to light-brown, darkening slightly at maturity;monad pollen;staminate bracteoles (scales) straw to orange-brown colored;mucilage glands present on the adaxial surface of leaf sheathes and adjacent blades. Leaves are 6-18 mm wide, mature pistillate spikes are 13-26 mm wide, and the pistillate and staminate spikes are separated by a gap of 0-8 cm. Some quantitative macroscopic characters including spike width, gap length between pistillate and staminate spikes, and leaf width are useful, but are too variable for conclusive identification, which depends on the above microscopic floral characteristics. Finlayson et al. (1985) combined measurements of the gap between male and female inflorescences with the length and diameter of the female inflorescences to distinguish T. domingensis from T. orientalis in Australia.

Impact

T. domingensis can spread prolifically by rhizomes after seedlings establish in disturbed vegetation, often forming monotypes that reduce wetland plant and animal diversity. The species thrives under eutrophic conditions and artificially stabilized hydroperiods, but in undisturbed, low-nutrient wetlands, T. domingensis often grows sparsely and does not appear to reduce diversity. T. domingensis is economically important in many regions as a weaving material, but when invasive, the species can replace other valuable plant commodities. Short-term Typha control is provided by cutting, burning, or grazing, each followed by flooding, or herbicide, but re-growth from rhizomes and a vast soil seed-bank complicate eradication.

Hosts

T. domingensis can invade the margins of rice fields and lacustrine cornfields (Sykes 1981, cited in Finlayson et al., 1983;Hall, 2008).
Host Plants and Other Plants Affected
Top of page
Plant name|Family|Context
Oryza sativa|
Zea mays subsp. mays (sweetcorn)|Poaceae
Biology and Ecology
Top of page
Genetics
T. domingensis readily hybridizes with other sympatric species of Typha. T. domingensis x latifolia has mostly abortive pollen and low seed set, while T. angustifolia x domingensis (reported in France and California) is highly fertile and can form hybrid swarms (Geze, 1912, cited in Smith, 1987;Smith, 1967). T. domingensis, T. latifolia, and T. angustifolia share n=15 chromosomes (Smith, 1967). T. domingensis shows ecotypic variation for a number of traits, including salt tolerance, germination temperature, time of flowering, height, rhizome proliferation, and rhizome number (McNaughton, 1966). Because of the worldwide distribution of T. domingensis, quantitative data presented here will likely vary widely among regional ecotypes.
Reproductive Biology
T. domingensis is protogynous, self-compatible, and does not show apomixis (Smith, 1967). Pollen requires strong winds for dispersal, and T. latifolia pollen can travel distances of at least one km (Krattinger, 1975). Despite copious pollen production, self-pollination appears to exceed outcrossing even in dense stands of T. latifolia. Some populations of T. domingensis remain in anthesis for more than a month (McNaughton, 1966). Each inflorescence can produce 600,000 fruits, or 6-17 million seeds per m 2 depending on flowering ramet density, and plants established from seed can flower by the second year (Prunster, 1940, cited in Finlayson et al., 1983;Howard-Williams, 1975). Germination can occur year-round in many climates, given adequate moisture, although germination declines below 20 ° C (Finlayson et al., 1983). In the United States, southern populations germinated at a lower temperature (13 ° C) than their northern counterparts (McNaughton, 1966). Seeds germinate under moist or submerged conditions;in an extreme case, T. domingensis germinated under 80 cm of water and survived for 8 weeks (Nicol and Ganf, 2000). Salinity reduces germination, although limited germination can occur even at 20% salinity (Beare and Zedler, 1987). High salinity prevented T. domingensis from recruiting after a lake drawdown in Malawi (Howard-Williams, 1975). Exposure to light and hypoxia increase germination (Sifton, 1959), which is low under established vegetation (Finlayson et al., 1983). In natural areas not disturbed by humans, disturbance and herbivory by animals could facilitate seedling establishment of Typha seedlings (Svengsouk and Mitsch, 2001).
Lateral rhizomes can facilitate rapid vegetative expansion after seedling establishment. Individual T. latifolia clones can span 60 m (Krattinger, 1983), and T. domingensis can spread laterally at 3-10 m/year (Parsons and Cutherbertson, 1992;Fraga and Kvet, 1993). Rhizome production is stimulated by short days and cold temperatures (McNaughton, 1966).
Physiology and Phenology
In frost-free climates, T. domingensis can produce ramets (culms) year-round, although most emerge in summer and autumn, and do not survive longer than 10 months (Finlayson et al., 1983;Parsons and Cuthbertson, 1992). In a spring-fed wetland in central Mexico, T. domingensis growing in dense stands did not produce new ramets between May and October unless disturbed by leaf harvest (Hall et al., in press). Flowering ramets differentiate by spring, and become fertile by early summer. Grace and Harrison (1986) contend that high rhizome carbohydrate supplies promote Typha ramets to flower rather than to remain vegetative. Repetitive harvesting decreased rhizome starch reserves and flowering ramet density of T. domingensis, but drought stress could promote flowering (Hall, 2008). Carbohydrate dynamics have been studied for T. latifolia. Leaf biomass is at a maximum while rhizome biomass is minimized in late summer. By autumn, leaf carbohydrates have been translocated to rhizomes, biomass increases, and rhizome starch concentrations are maximized (Linde et al., 1976). For T. domingensis in Belize, leaf turnover averages 110 days (Rejmankova et al., 1996). Fraga and Kvet (1993) report that T. domingensis in Cuba had a net primary productivity of 1500 g/m 2 /year. Litterbag experiments showed only 50% decomposition after one year, and organic matter accumulated rapidly.
In flooded conditions, oxygen is conducted to Typha ’s underwater tissues via leaf aerenchyma cells (Sale and Wetzel, 1983), allowing T. domingensis to tolerate water 2 m deep (Finlayson et al., 1983). Flooded seedlings only produced additional ramets, however, when they reached the water surface (Nicol and Ganf 2000). T. domingensis is moderately salt-tolerant, and salinities of up to 5% should not impede vegetative growth or flowering. Salinity 5% prevents growth, and salinity 25% causes leaf mortality, although rhizomes re-sprout if salinity declines (Beare and Zedler, 1987). Freshwater inflows lasting 2 months allowed T. domingensis to invade California salt marshes. T. domingensis thrives in hot climates, and grows well in water at 30 ° C (Finlayson et al., 1983). Parsons and Cuthbertson (1992) reported maximum growth at 32 ° C, declining to 50% at 18 ° C. Typha spp. show a high tolerance for soil and water contaminated by heavy metals (McNaughton et al., 1974).
Nutrition
T. domingensis thrives under high nutrient loads and stable, prolonged, hydroperiods. In the Florida Everglades, T. domingensis invasion correlated with increased phosphorus and water levels, and muck-burning fires (Urban et al., 1993;Newman et al., 1998). Typha ’s limitation by phosphorus is supported by a comparison of soil and plant tissue samples from eutrophic and un-impacted areas of the Everglades (Koch and Reddy, 1992). T. domingensis also appeared limited by phosphorus in wetlands of Mexico’s Yucatan Peninsula and Belize (Rejmankova et al., 1996). In mesocosms, elevated nutrient levels and prolonged hydroperiods increased T. domingensis biomass and tissue phosphorus concentration relative to the co-occurring Cladium jamaicense (Newman et al., 1996). Substantial peat, nitrogen, and phosphorus accumulated where T. domingensis dominated nutrient-rich areas of the Everglades (Craft and Richardson, 1993). Seedlings produced more biomass, had a greater root/shoot ratio, and contained more phosphorous when grown in burned soil than in unburned or surface-burned soil in the Everglades, suggesting that soil-burning fires promote T. domingensis by releasing phosphorus (Smith and Newman, 2001). In low-nutrient areas of the Everglades, Typha is present but does not dominate (Davis, 1994).
Nitrogen and phosphorus appeared to co-limit the congener T. latifolia when it was grown in mesocosms, whereas in the field, T. latifolia increased along a gradient of increasing phosphorus (Svengsouk and Mitsch, 2001). T. x glauca required both nitrogen and phosphorus for growth in a greenhouse experiment, but adding a higher proportion of phosphorus stimulated growth regardless of nutrient concentration (Woo and Zedler, 2002).
Associations
In disturbed and eutrophic wetlands, T. domingensis tends to form monotypes. However, T. x glauca ’s invasive growth may be dependent on anthropogenic modifications (e.g. from dams, wastewater discharge, or irrigation canals). In little-disturbed wetlands where hydroperiods fluctuate seasonally, many genera co-occur with T. domingensis. In Australian wetlands, Baumea, Eleocharis, Gahnia, Melaleuca, Muehlenbeckia, and T. orientalis co-dominate with T. domingensis where water levels fluctuate (Finlayson et al., 1983;Nicol and Ganf, 2000). In Cuba, Bidens, Cyperus, Eleocharis, Hyparrenia, Panicum, and Sagittaria can co-occur with T. domingensis in shallow water, although T. domingensis often forms temporary monotypes in deeper water (Fraga and Kvet 1993). In this system, shrubs can replace Typha because of rapid organic matter accumulation;frequent fire might reduce litter and retard succession. In Africa’s Lake Victoria, T. domingensis is less abundant than the dominant Cyperus or Miscanthidium (Kansiime et al., 2007);in Lake Chad, Vossia, Cyperus, and Phragmites dominate, while T. domingensis is rare (Denny, 1985a). Thompson (1985) ranked T. domingensis as the third most-dominant African wetland plants, behind Phragmites australis and P. mauritianus. In Belize, T. domingensis normally dominates on clay soils with low salinity, while growing sparsely with dominant Eleocharis and Cladium on marl and sandy soil with higher salinity (Rejmankova et al., 1996). T. domingensis monotypes in this region may be relics of phosphorus-rich agricultural run-off. In Iran, T. domingensis and Schoenoplectus tabernaemontani co-dominate diverse wetlands (Karami et al., 2001). In a groundwater-fed wetland in central Mexico, harvesting T. domingensis increased species richness and the recruitment of uncommon species (Hall, 2008). Here, more than 40 species co-occurred with Typha and the co-dominant Schoenoplectus americanus.
Environmental Requirements
T. domingensis tolerates a broad climatic spectrum, growing between 40 ° latitude north and south under a variety of rainfall regimes (Smith, 2000). Although T. domingensis tolerates widely variable hydroperiods, it can decline during extended drawdowns, and grows best under flooded conditions (Rejmankova et al., 1996;Palma-Silva et al., 2005). Rainfall does not appear to limit wide-scale geographic distribution, because even in seasonally dry climates (e.g. central Mexico), T. domingensis can persist in isolated springs or on lakeshores. Seedlings can tolerate anaerobic conditions, but mature plants are intolerant of anaerobic conditions created when leaves are severed below water (Sale and Wetzel, 1983).
Climate
Top of page
Climate|Status|Description|Remark
Af - Tropical rainforest climate| Preferred
60mm precipitation per month
Am - Tropical monsoon climate| Preferred
Tropical monsoon climate (60mm precipitation driest month but (100 - [total annual precipitation(mm}/25]))
As - Tropical savanna climate with dry summer| Preferred
60mm precipitation driest month (in summer) and (100 - [total annual precipitation{mm}/25])
Aw - Tropical wet and dry savanna climate| Preferred
60mm precipitation driest month (in winter) and (100 - [total annual precipitation{mm}/25])
BS - Steppe climate| Preferred
430mm and 860mm annual precipitation
BW - Desert climate| Preferred
430mm annual precipitation
C - Temperate/Mesothermal climate| Preferred
Average temp. of coldest month 0°C and 18°C, mean warmest month 10°C
Cf - Warm temperate climate, wet all year| Preferred
Warm average temp. 10°C, Cold average temp. 0°C, wet all year
Cs - Warm temperate climate with dry summer| Preferred
Warm average temp. 10°C, Cold average temp. 0°C, dry summers
Cw - Warm temperate climate with dry winter| Preferred
Warm temperate climate with dry winter (Warm average temp. 10°C, Cold average temp. 0°C, dry winters)
Latitude/Altitude Ranges
Top of page
Latitude North (°N)|Latitude South (°S)|Altitude Lower (m)|Altitude Upper (m)
40
40
0
0
Soil Tolerances
Top of page
Soil drainage
impeded
seasonally waterlogged
Soil reaction
acid
alkaline
neutral
Soil texture
heavy
light
medium
Special soil tolerances
infertile
other
saline
shallow
sodic
Notes on Natural Enemies
Top of page
Herbivory is common but variable. In Australia, kangaroos, rodents, and water birds lightly graze T. domingensis, while water buffalo can cause heavy damage (Finlayson et al., 1983). In Africa, large herbivores do not extensively feed on T. domingensis, despite its abundance (Howard-Williams and Gaudet 1985). In Costa Rica and elsewhere throughout Latin America, cattle heavily graze T. domingensis (McCoy et al., 1994). Muskrats (Ondatra zibethicus) can eliminate entire stands of Typha spp. through herbivory, at least in temperate climates (Kadlec et al., 2007). Barreto et al. (2000) mention a variety of fungal pathogens, although none have been extensively studied in the field. A variety of insects feed on T. latifolia and T. angustifolia. Lepidopteran larvae often inhabit inflorescences, while noctuid caterpillars and coleoptera attack leaves, stalks, and sometimes rhizomes (Grace and Harrison, 1986).
Means of Movement and Dispersal
Top of page
Natural Dispersal (Non-Biotic) Typha ’s tiny seeds (1 - 2 mm long) are contained in achenes attached to pistil hairs, and are often dispersed by the wind. Spikes do not shed fruits until they have dried (Krattinger, 1975), often delaying dispersal until many months after seed maturation. The entire female spike sometimes collapses in place, providing a floating platform for germination (Hall, 2008). Masses of achenes and hairs, and rhizomes, can disperse by floating on currents of water (Grace and Harrison 1986;Parsons and Cutherbertson, 1992).
Vector Transmission (Biotic)
When achenes are moistened, seeds are released, which have a pointed end that can become embedded in fish scales (Krattinger, 1975). Also, pistil hairs (with attached acenes) adhere to the clothing of fieldworkers, and could attach to animals as well (S Hall, University of Wisconsin, USA, personal communication, 2008). Mud with embedded seeds readily sticks to humans, livestock, birds, and agricultural implements (Parsons and Cuthbertson, 1992).
Intentional Introduction
Indigenous people in the Northwestern United States propagated T. latifolia using rhizome fragments (Turner and Peacock, 2005). Similar propagation of T. domingensis has not been documented.
Pathway Causes
Top of page
Cause|Notes|Long Distance|Local|References
Crop production|Seeds attach to mud on agricultural implements.| Yes
Parsons and Cuthbertson,
1992
Disturbance|Seedlings establish in disturbed vegetation.| Yes
Finlayson et al.,
1983
Hitchhiker|Achenes with hairs attach to humans and animals.| Yes
Yes
Parsons and Cuthbertson,
1992
Interbasin transfers|Achenes and rhizomes disperse with water currents.| Yes
Grace and Harrison,
1986;Parsons and Cuthbertson,
1992
Interconnected waterways|Achenes and rhizomes disperse with water currents.| Yes
Grace and Harrison,
1986;Parsons and Cuthbertson,
1992
Self-propelled|Achenes with hairs are wind-dispersed.| Yes
Krattinger,
1975
Pathway Vectors
Top of page
Vector|Notes|Long Distance|Local|References
Clothing, footwear and possessions|Achenes with hairs.| Yes
Parsons and Cuthbertson,
1992
Host and vector organisms|Achenes adhere to fish scales.| Yes
Krattinger,
1975
Water|Achenes with hairs, rhizomes.| Yes
Grace and Harrison,
1986;Parsons and Cuthbertson,
1992
Wind|Achenes with hairs.| Yes
Yes
Krattinger,
1975
Impact Summary
Top of page
Category|Impact
Economic/livelihood
Positive and negative
Environment (generally)
Positive and negative
Economic Impact
Top of page
T. domingensis can interfere with agriculture in wet areas. With the adoption of year-round rice cropping in Australia, T. domingensis invaded fields and decreased yields by 5% (Sykes 1981, cited in Finlayson et al., 1983). In central Mexico’s Lake Pátzcuaro, T. domingensis can invade low-lying cornfields. This species also tends to replace the bulrush Schoenoplectus californicus, a valuable species traditionally used to weave mats (Hall, 2008). In southern Mexico, T. domingensis invades wetlands used for horse pasture, and replaces valuable fodder (S Hall, University of Wisconsin, USA, personal communication, 2009). In lacustrine wetlands, T. domingensis can interfere with fishing and water transportation (Mitchell, 1985).


Source: cabi.org
Description

Adult Papuana huebneri are black, shiny and 15-20 mm long. The size and number of head horns in taro beetles varies between species and sexes;P. huebneri has only one small horn, which is larger in the male than the female (Macfarlane, 1987a).

Recognition

Taro beetles can be detected by: (1) digging up wilting taro plants and examining them for signs of damage;(2) using light traps, particularly on moonless and rainy nights;and (3) sampling wild plant species (e.g. banana, sugarcane and grasses such as Paspalum spp. and Brachiaria mutica) at breeding sites, especially along river banks, on rotting logs and in compost heaps (Carmichael et al., 2008;Tsatsia and Jackson, 2014;TaroPest, 2015).

Symptons

Adult taro beetles burrow into the soft trunks, plant bases and corms of a range of plants, including taro, making large holes or cavities up to 2 cm in diameter (McGlashan, 2006). The feeding tunnels and associated frass may be visible in infested corms (Biosecurity Australia, 2011). The amount of damage to the crop depends on the age of the plants when attacked and the density of infestation. Feeding activity can cause wilting and even the death of affected plants, particularly in young plants if the beetles bore into the growing points. Older plants infested by beetles grow slowly and a few or all of the leaves wilt (TaroPest, 2015). In severely damaged plants tunnels may run together to form large cavities, making the damaged corms more susceptible to fungal infections (Macfarlane, 1987a;Onwueme, 1999). Similar symptoms of damage are caused to other root crops, e.g. sweet potato, yams and potato (McGlashan, 2006). Taro beetles can ring-bark young tea, cocoa and coffee plants in the field and bore into seedlings of oil palm and cocoa (Aloalii et al., 1993).

Impact

Papuana huebneri is one of at least 19 species of known taro beetles native to the Indo-Pacific region;it is native to Papua New Guinea, the Molucca Islands in Indonesia, the Solomon Islands and Vanuatu, and has been introduced to Kiribati. Taro (Colocasia esculenta) is an important crop in these countries;high infestations of P. huebneri can completely destroy taro corms, and low infestations can reduce their marketability. The beetle also attacks swamp taro or babai (Cyrtosperma chamissonis [ Cyrtosperma merkusii ]), which is grown for consumption on ceremonial occasions. Infestations of taro beetles, including P. huebneri, have led to the abandonment of taro and swamp taro pits in the Solomon Islands and Kiribati, resulting in the loss of genetic diversity of these crops and undermining cultural traditions. P. huebneri also attacks a variety of other plants, although usually less seriously. Management today relies on an integrated pest management strategy, combining cultural control measures with the use of insecticides and the fungal pathogen Metarhizium anisopliae.

Hosts

Papuana huebneri is a pest of taro (Colocasia esculenta;known as ‘dalo’ in Fijian;McGlashan, 2006) (Masamdu, 2001;International Business Publications, 2010), which is grown primarily as a subsistence crop in many Pacific Island countries, including Kiribati, Papua New Guinea, the Solomon Islands and Vanuatu, where P. huebneri is found (Aloalii et al., 1993). Taro also has value in gift-giving and ceremonial activities (Braidotti, 2006;Lal, 2008). The beetle also attacks swamp taro or babai (Cyrtosperma merkusii or Cyrtosperma chamissonis), which is grown for consumption on ceremonial occasions (Food and Agriculture Organization, 1974;Dharmaraju, 1982;International Business Publications, 2010).
Other plants attacked by Papuana huebneri include tannia (Xanthosoma sagittifolium), bananas (Musa spp.), Canna lily (Canna indica), pandanus (Pandanus odoratissimus [ Pandanus utilis or P. odorifer ]), the bark of tea (Camellia sinensis), coffee (Coffea spp.) and cocoa (Theobroma cacao), the fern Angiopteris evecta (Masamdu, 2001), and occasionally the Chinese cabbage Brassica chinensis [ Brassica rapa ] (International Business Publications, 2010).
Species of Papuana behave similarly to each other and feed on the same host plants (TaroPest, 2015). For taro beetles in general, primary host plants other than taro include giant taro (Alocasia macrorrhizzos), Amorphophallus spp., the fern Angiopteris evecta, banana (Musa spp.) and tannia (Xanthosoma sagittifolium). Secondary hosts include pineapple (Ananas comosus), groundnut (Arachis hypogaea), betel nut (Areca catechu), cabbage (Brassica oleracea), canna lily (Canna indica), coconut (Cocos nucifera), Commelina spp., Crinum spp., yam (Dioscorea spp.), oil palm (Elaeis guineensis), sweet potato (Ipomoea batatas), Marattia spp., pandanus (Pandanus odoratissimus [ Pandanus utilis or P. odorifer ]), Saccharum spp. including sugarcane (Saccharum officinarum) and Saccharum edule [ Saccharum spontaneum var. edulis ], and potato (Solanum tuberosum);they occasionally ring bark young tea (Camellia sinensis), coffee (Coffea spp.) and cocoa (Theobroma cacao) plants (Macfarlane, 1987b;Aloalii et al., 1993;Masamdu and Simbiken, 2001;Masamdu, 2001;Tsatsia and Jackson, 2014;TaroPest, 2015).


Source: cabi.org
Damage Myzus cerasi
Title: Myzus cerasi
Description

M. cerasi is a small to medium-sized aphid. Adults are shiny, very dark brown to black, with a sclerotized dorsum. Siphunculi and cauda are entirely black. The legs and antennae are yellow and black.
Fundatrices differ from apterous summer virginoparae in having relatively shorter antennae (0.75-1.15 cf. 1.25-1.60 mm) and hind tibiae (0.60-0.70 mm);otherwise similar (Palmer, 1952).
Apterous summer virginoparae have a shiny black body, siphunculi and antennae. Cauda dusky to black, and tibiae yellow except tips. The siphunculi are somewhat broader at the base, constricted just before definite flange, curved outwards, and, when at rest, are held against the body so that the tips converge and nearly touch. Cauda is rather broad at base and strongly tapered, bearing 2-3 lateral pairs of hairs (Palmer, 1952). Apterae on secondary host-plants can sometimes vary in colour from dark brown to olive-green or yellowish-brown. Apterae body lengths in range 1.5-2.6 mm (Blackman and Eastop, 1984).
Alate virginoparae have a yellow-brown abdomen, with a large black central dorsal patch. Colours otherwise as apterous virginoparae. Siphunculi cylindrical, less tapered and curved than in apterous virginoparae. Cauda tapered to nearly cylindrical and bearing 2-3 pairs of lateral hairs. Alatae body length in range 1.4-2.1 mm (Palmer, 1952;Blackman and Eastop, 1984).
Oviparae are apterous. Body length around 1.10 mm. Hind tibiae with proximal half slightly swollen (Palmer, 1952).
Males are alate. Deep black, with all appendages black except yellow tibiae. Body length around 1.30 mm (Palmer, 1952).
Morphology varies, however, with geographic region. Aphids collected in India differed from those collected in Japan and elsewhere in not having entirely black siphunculi and cauda, and differed from those collected in Australia by having paler dorsum and shorter processus terminalis (Raychaudhuri, 1980).
Diploid chromosome number is 2n=10 (Blackman and Eastop, 1984). Some Indian populations have been reported as having 2n=12;these are probably the subspecies M. cerasi umefoliae (Blackman and Eastop, 1994).

Recognition


Colonies can be found via inspection of curled young growing shoots of cherry trees in the spring. Winged M. cerasi in cherry orchards later in the spring and early summer can be detected using yellow sticky traps.

Symptons


Colonies of M. cerasi form dense colonies at the growing apices of cherry trees in spring. Initial damage is due to leaf curling. Continual feeding causes deformation of shoot growth and can also lead to the formation of pseudogalls (open galls). Galling is thought to be due to the action of aphid saliva, which contains a physiologically-active substance (alpha-glucosidase) known to influence plant growth.

Hosts


Primary host plants are Prunus cerasus (Morello cherry) and Prunus avium (sweet cherry), and sometimes other Prunus species (Rosaceae). Secondary hosts occur in the Rubiaceae (Galium spp.), Scrophulariaceae (Veronica spp.) and Cruciferae (Capsella spp.), and occasionally Caprifoliaceae and Compositae. Different secondary hosts are utilized in different geographical regions, for example, cruciferous hosts are important in the USA (Gilmore, 1960;Blackman and Eastop, 1984).


Source: cabi.org
Title: Myzus cerasi
Description

D. suzukii adults are 2-3 mm long with red eyes, a pale brown or yellowish brown thorax and black transverse stripes on the abdomen. The antennae are short and stubby with branched arista. Sexual dimorphism is evident: males display a dark spot on the leading top edge of each wing and females are larger than males and possess a large serrated ovipositor.

Recognition


Detailed morphological description of each stage is given by Kanzawa (1935). A more recently updated description, including references for additional morphological details, is given by Hauser (2011), and another by Vlach (2010), who published a dichotomous key for easy identification. An easy-to-use description of the combination of diagnostic characters that could be used for tentative identification of D. suzukii within its subgroup is given by both Hauser (2011) and Cini et al. (2012). Fruit infestation symptoms are described by Walton et al. (2010).
The dark spots on the male wings together with two sets of black tarsal combs make the identification of the males relatively easy, although the males of some other species do also have wing spots. The wing spots of D. subpulchrella are particularly similar in shape and position to those of D. suzukii. Males without dark wing spots can occur, as it takes two full days before the spots become obvious, although they start to appear within 10 hours of emergence at high temperatures.
The situation is complex for the eggs, larvae and pupae, as no reliable morphological diagnostic features have been identified (Okada, 1968). The eggs of D. suzukii have two respiratory appendages but this character is not species-specific. Instar stages can be estimated by the size of larvae and the colour of the mouthparts, but it is most accurately judged by pre-respiratory ducts (Kanzawa, 1935;Walsh et al., 2011).
Larvae are often undetected inside the fruit. The infested fruits can be detected only by visual inspection under optical magnification (15-20 x magnification). Detection of larvae inside the fruits can also be performed by immersion of fruit samples in sugar or salt solution. Sugar solution can be prepared using approximately 1 part sugar to 6 parts water in order to reach at least 15°Brix. Gently crush the fruits and wait for 10 minutes until the larvae in the sample float to the surface. The same procedure can also be followed using a salt solution, adding 1 part salt to 16 parts water (BCMA, 2013).
Traps baited with different baits have been proposed for detecting adults in the field. Traps can be installed around a site where fruits for shipment are stored, and for early detection in potentially newly-invaded areas, such as near fruit markets, warehouses of food retailers and sites where rotten fruits are disposed. For more information on traps and baits, see the Monitoring and Surveillance section in Prevention and Control.

Symptons

D. suzukii larvae cause damage by feeding on the pulp inside fruit and berries. The infested fruit begins to collapse around the feeding site causing a depression or visible blemish on the fruit. The oviposition scar exposes the fruit to secondary attack by pathogens and other insects, which may cause rotting (Hauser et al., 2009;Walton et al., 2010).

Impact


The fruit fly D. suzukii is a fruit crop pest and is a serious economic threat to soft summer fruit. A polyphagous pest, it infests a wide range of fruit crops, included grape, as well as an increasing number of wild fruits. D. suzukii is an economically damaging pest because the females are able to infest thin-skinned fruits before harvest and the larvae destroy the fruit pulp by feeding. The species is endemic in Asia. It was first recorded as invasive in Hawaii in 1980 and then simultaneously in California and in Europe in 2008. Since 2008 it has spread rapidly throughout the temperate regions of North America and Europe, due to global trade and the initial lack of regulation over the spread of any Drosophila. This species has a high reproductive rate and short generation time;D. suzukii can theoretically have up to 13 generations per year, which may contribute towards rapid spread, given available suitable hosts. D. suzukii is listed on the EPPO alert list.

Hosts

D. suzukii is predisposed towards infesting and developing in undamaged, ripening fruit. Fruits become susceptible to D. suzukii as they start to change colour, which coincides with softening skins and higher sugar levels (Burrack et al., 2013). There are differences in fruit susceptibility within species and among varieties within the same fruit species (Lee et al., 2011). Fruit penetration force is one potential measure of host susceptibility, but host attractiveness will likely depend upon additional factors, such as soluble sugar content (Burrack et al., 2013). If there is no suitable fruit available, then D. suzukii will attack damaged or deteriorating fruit (Kanzawa, 1935;Lee et al., 2011). Non-commercially marketed fallen fruit or damaged fruit of the following plant hosts may also be attacked: Prunus persica, Malus pumila var. domestica, Prunus triflora, Prunus armeniaca, Pyrus pyrifolia, Pyrus sinensis, Eriobotrya japonica, Lycopersicum esculentum (Kanzawa, 1939) and Rubus microphyllus (Mitsui et al., 2010), as well as over-ripped figs still on the tree (Ficus carica) (Yu et al., 2013).
D. suzukii has been reared from rotting strawberry guava fruits (Psidium cattleianum) collected from trees and on the ground (Kido et al., 1996). It has been observed feeding upon injured or culled fruit including apple and oranges (Walsh et al., 2001).
A recently extensive study on seasonal life cycles and food resources of D. suzukii from low to high altitudes in central Japan (Mitsui et al., 2010) confirmed that D. suzukii emerges almost only from fruits. Some D. suzukii individuals emerged from the fruits of Rubus crataegifolius, Alangium platanifolium, Cornus kousa, Torreya nucifera and Viburnum dilatatum. Grassi et al. (2011) reared D. suzukii also on Prunus laurocerasus and Mann and Stelinski (2011) reported Ribes spp. as host plant of D. suzukii, but this latest observation has not been confirmed in Europe. D. suzukii adults also emerged from the flowers of Styrax japonicus (Mitsui et al., 2010), and in early spring in southern Japan it was also observed to breed on the flowers of Camellia japonica (Nishiharu, 1980).
This field of work is not well described, and so the list of Host Plants and Other Plants Affected contains probable as well as reported hosts.

Biological Control
Early experiments tested the efficacy of Phaenopria spp. (Hymenoptera: Diapriidae) under laboratory conditions, but results were unsatisfactory (Kanzawa, 1939).<br>Studies to determine the current presence of indigenous parasitoid biological control agents and their efficacy in controlling D. suzukii were undertaken both in North America and in Europe by different research groups (Brown et al., 2011;Chabert et al., 2012;Rossi Stacconi et al., 2013). Under laboratory conditions several naturally occurring parasitoids of drosophilids in France were able to successfully parasitize D.suzukii. These included two larval parasitoids, Leptopilina heterotoma and Leptopilina boulardi, and two pupal parasitoids, Pachycrepoideus vindemiae (Hymenoptera: Pteromalidae) and Trichopria drosophilae (Hymenoptera: Diapriidae). Both Leptopilina parasitoids displayed high parasitism rates on D. suzukii, but because of the strong immune response of the host larvae, they did not give rise to an adult wasp (Chabert et al., 2012).<br>D. suzukii produces up to five times more hemocytes than D. melanogaster, making it significantly more resistant to wasp parasitism (Kacsoh and Schlenke, 2012) and making it less likely for indigenous specialized parasitoids to shift host onto it. While parasitization by L. heterotoma induced a decrease in the number of circulating haemocytes in D. melanogaster, it led to a large increase in the total haemocyte counts of D. suzukii (Poyet et al., 2013).<br>The observed difference between the immune response towards L. heterotoma in D. suzukii and D. melanogaster could suggest that European populations of L. heterotoma are not adapted to this new exotic host (Poyet et al., 2013);however, this hypothesis disagrees with the recent observations of a European-wide strain of L. heterotoma that is able to develop and emerge from D. suzukii. (Rossi Stacconi et al., 2013). It is probable that the European-wide strain of L. heterotoma has more effective venom, or that the strain of L. heterotoma used in the original study had lost its ability to develop on D. suzukii because of continued laboratory rearing on D. melanogaster.<br>Pupal parasitoids seem less susceptible to the high hemocyte levels of D. suzukii and they appear to have the highest potential for use in biocontrol of D. suzukii (Kacsoh and Schlenke, 2012). This was confirmed by the successful parasitism rate obtained with a pupal parasitoid by Chabert et al. (2012).<br>The pupal ectoparassitoid P. vindemiae has also been found in association with D. suzukii in orchards and vineyards, both in USA and in Europe (Brown et al., 2011;Rossi Stacconi et al. 2013).<br>Predators of D. suzukii include several species of the bug genus Orius, a generalist predator, which were observed feeding on D. suzukii larvae in backyard raspberries in the autumn of 2009 (Walsh et al., 2011). Preliminary laboratory studies with O. insidiosus (Walsh et al., 2011), O. laevigatus and O. maiusculus (V. Malagnini, personal comm.) indicated that they can feed on D. suzukii larvae infesting blueberries, but their effective control of the pest population have not been proved yet.<br>The activity of microorganisms, as well as the intimate association of the pest species with endosymbionts, has not yet been exploited for biocontrol purpose.<br>Recently, DNA viruses have been isolated in Drosophila species (Unkless, 2011) and were found to be related to other viruses used for pest control.<br>Strains of endosymbiotic bacterium Wolbachia associated with D. suzukii populations have been collected in both the USA and Italy (Siozios et al., 2013;Tochen et al., 2014). These findings suggest the possibility of control of D. suzukii based on pathogens.

Source: cabi.org
Damage Mealybug
Description

O. acuta is a bisexual species with multiple generations annually. This species is distinguished by the morphology of the adult female. No descriptive information on the morphology of the immature or adult male stages exists at present [2010]. The live adult females are pink and covered with a white powdery, waxy secretion. The females are uniquely found enclosed within whitish resinous cells that are open at one end, from which their pygidia protrude. The cells are usually attached to the stem at the base of the needle.

Symptons

The extraction of sap by the feeding mealybugs in the area of the fascicle may lead to excessive resin flow resulting in the needles turning brown and eventually dropping off (Xu et al., 1992, Pan et al., 1994, Sun et al., 1996). High populations of the mealybug can potentially cause malformed growth, loss of plant vigour, stunting, defoliation, reduced seed production, and potential death of the plant, if not treated. The mealybugs are often found in the pitch cells located on new growth needles or on a short section of the stem immediately below the buds in the southern USA. However, the mealybugs are found completely covering the needles and shoots on pine branches in China. Heavy populations of the loblolly pine mealybug have been reported to severely damage slash pine cones that result in them being smaller than normal, deformed or crescent-shaped, and a reduction in seed production results (Sun et al., 1996). Also, the production of vast amounts of honeydew serves as a substrate for the development of sooty mould that blackens the branches, stems, and needles. These weakened trees are susceptible to attacks by other insects.

Biological Control
The transfer of O. acuta from the USA to hosts in China, thus, leaving behind those natural enemies that maintained the population at low levels allowed for its establishment and rapid population growth in the new region. Upon the discovery of the invasive O. acuta and its damage to slash pine [ Pinus elliottii ] stands in the Guangdong Province, a two-year search to find potential native natural enemies in the infested pine stands was employed. From field evaluations, it was concluded that in the absence of natural enemies, populations of O. acuta increased 1.26 times per generation (Tang et al., 1996). In studies to assess potential natural enemies of the loblolly pine mealybug in China, the predaceous Cryptolaemus montrouzieri was determined to have some potential in regulating the pest populations (Tang, 1994, Tang et al., 1995a, Pan et al., 2002). One discovered parasitoid, Allotropa sp., was found to be ineffective against the loblolly pine mealybug. Cooperative efforts between the USA and China were initiated to evaluate the natural enemies of O. acuta as potential biological control agents to import into China to suppress infestations of the pest. Nine parasitoid species have been found to be associated with O. acuta (Clarke et al., 1990a, Sun et al., 1998, 2004a,b, Masner et al., 2004). Of these, two species, Allotropa oracellae and Zarhopalus debarri, are consider primary parasitoids for use against the loblolly pine mealybug.

Source: cabi.org
Description

B. phoenicis is a highly variable species, but can be readily distinguished in the adult stage from the other members of the genus by having five pairs of dorsolateral hysterosomal setae and two sensory rods on tarsus II. The chaetotaxy of false spider mite is described according to Haramoto (1969).
The larvae and nymphs also have five pairs of dorsolateral hysterosomal setae, but unlike the adults they have only one sensory rod, located posteriodistally on tarsus II. Morphologically, the immature stages of B. phoenicis resemble those of B. obovatus, and like the latter they are subjected to considerable variation in size and shape of some of the dorsal setae. The number and arrangement of the setae on the dorsum of idiosoma of the larva, protonymph and deutonymph conform to those of the adult and to the genus Brevipalpus (Pritchard and Baker, 1951). Twelve pairs of setae are present on the dorsum, three pairs on the propodosoma and nine pairs on the hysterosoma. Of the dorsal setae, dorsolateral hysterosomal setae I and II and dorsocentral hysterosomal seta III are the most variable in size and shape, varying from tiny and serrate to large, broadly lanceolate and serrate, similar to dorsal propodosomal setae II and III. The number of setae on the venter is not constant but increases from four pairs on the larva, five pairs on the protonymph, seven pairs on the deutonymph to eight pairs on the adult. These additions take place in the hysterosomal regions of the body. A pair of medioventral opisthosomal setae is present in the two nymphal and adult stages but not in the larval stage. The medioventral propodosomal setae, which are present in the larval, nymphal and adult stages, and the posterior medioventral metapodosomal setae, which are present only in the deutonymphal and adult stages, are filamentous and smooth. The remaining ventral setae are smooth.
In general, the size of an individual of a stage varies according to the availability of resources (Dosse, 1952). The average size (in µm) of different stages is given below according to Nageshchandra and Channabasavanna (1974b).
Body dimensions (µm):
Egg, L 90, W 59;larva, L 145, W 102;protonymph, L 192, W 115;deutonymph, L 238, W 135;adult male, L 268, W 135;adult female, L 277, W 140.
Length of legs (µm):
Larva, I 61, II 45, III 42;protonymph, I 77, II 61, III 52, IV 56;deutonymph, I 100, II 82, III 75, IV 77;adult male, I 147, II 126, III 112, IV 130;adult female, I 142, II 121, III 114, IV 121. These values reveal that the growth of this mite is rather rapid until it reaches the deutonymphal stage, and then is more or less static. The reason might be that in the adult stage most of the food consumed is utilized for the production of eggs, whereas in the earlier stages it is used for its own growth. These mites live longer than other Tetranychid mites, but are half the size.

Recognition


A diagnostic Lucid key to 19 species of Brevipalpus is available in Flat Mites of the World.

Symptons


Although false spider mite is considered to be polyphagous, it is thought to cause serious crop losses on citrus (Muma, 1964;Knorr and Denmark, 1970), tea (Baptist and Ranaweera, 1955;Rao, 1970;Danthanarayana and Ranaweera, 1972;Kalshoven and van der Laan, 1981;Oomen, 1982) and papaya (Haramoto, 1969). Losses on citrus due to this mite can be enormous.
Mites belonging to the family Tenuipalpidae feed in the same way as the Tetranychidae, by continually punching the leaf epidermis with their chelicerae (Jeppson et al., 1975). The sap that oozes out of the wounded leaf cells is mixed with saliva and imbibed into the digestive tract of the mite (Haramoto, 1969). The necrotic spots are visible as a brownish, shaded area on the affected leaves, and the affected leaf can be seen filled with red coloured eggs and white empty moults (Oomen, 1982).
In tea, damage is caused by sucking sap from the stems and leaves, producing a characteristic necrotic brown spot extending along the midribs and borders of the leaves. The whole underside becomes brown, which may lead to defoliation and subsequently reduce the production of green tea leaves (Benjamin, 1968;Oomen, 1982). It is typical for affected bushes to have a thin canopy of maintenance leaves causing increased light penetration into the frame of the bush, which permits the growth of mosses and lichens. This is a traditional indication to planters that the tea bushes are in poor condition, although they are often not aware of the relation with false spider mite infestation.
On papaya plants, this mite usually feeds on the trunk at the level where the bottom whorl of leaves is attached. As intraspecific competition for food and space intensifies, the mites feed upwards on the trunk and outwards onto the leaf petioles and fruits, leaving a large, conspicuous, damaged area behind them. The immediate area around the feeding puncture becomes raised and blister-like, as though caused by a toxic substance. Later the affected tissue dries up, dies and becomes discoloured. As many punctures occur close together, the affected areas coalesce to form a large and continuous area which is callous-like, tannish and scaly and/or scabby. The feeding becomes pronounced when young papaya fruits are attacked, as the affected areas become sunken due to the differential growth of the injured and uninjured tissues. The mites sometimes puncture the latex glands while feeding, causing a copious outflow of a milky white liquid that mars the appearance of the fruits. All stages of the mite in the path of the flow of sticky latex are engulfed and drowned in it. The papaya stem, which normally remains green for a long time, becomes tannish and suberized in appearance, and makes spindly growth when heavily infested by B. phoenicis (Haramoto, 1969).
The damage caused by false spider mite is of a higher magnitude on citrus than any other crop plants, including tea and papaya. On citrus, it can cause Brevipalpus gall and halo scab with phoenicis blotch - a combination of fungus and mite attack (Knorr and Denmark, 1970;Carter, 1973). Plants attacked by the mite produce galls in the nodal region, which eventually the hinder the sprouting of new buds. The gall-like protuberances may be barely visible and woody. They look like axes that have proliferated to resemble a bud-studded cushion. No leaves develop at the axis occupied by these cushions, and when the buds are replaced by the cushions the trees become devoid of leaves and soon die. Gall formation follows the initial loss of leaves;adventitious buds sprout but are successively killed, producing hypertrophies at the bud loci (Knorr et al., 1960;Knorr, 1964;Jeppson et al., 1975). This type of symptom is common among seedlings, which ultimately die. The fungus Elsinoë fawcetti causes scab on sour orange without causing leaf drop;however, when scab lesions are also colonized by B. phoenicis, leaf drop is conspicuous. The combination of fungus and mite attack in the nursery could pose a serious problem. High populations of false spider mite are associated with a diffuse chlorotic spotting in orange trees. When such chlorotic spottings increase, they reduce the area of photosynthesis, ultimately reducing fruit production. As well as causing feeding damage, the mite transmits a viral disease caused by citrus leprosis rhabdovirus (Kitajima et al., 1972;Carter, 1973). A disease of oranges known in Argentina as 'lepra explosiva', originally thought to be caused by a fungus (Marchionatto, 1935) and later by a virus (Marchionatto, 1938;Blanchard, 1939), is now attributed to toxins injected by Brevipalpus obovatus in the process of feeding (Carter, 1952). B. phoenicis has also been collected from orange trees exhibiting these symptoms in Paraguay (Nickel, 1958).
In addition to these symptoms, B. phoenicis can cause pitting and splitting of the skin of orange fruits (Planes, 1954);scarring of tangerine fruits (Nickel, 1958);defoliation and vine dieback of passion fruit (Haramoto, 1969);and splitting of guava fruits (Nageshchandra and Channabasavanna, 1974b). It also transmits coffee ringspot virus disease on coffee (Chagas, 1973).

Hosts


The first report of a host plant of B. phoenicis was Phoenix sp., a greenhouse palm (Geijskes, 1939). Since then, many different plants have been reported as infested by this species of mite in different parts of the world (Cromroy, 1958;Pritchard and Baker, 1958;Baker and Pritchard, 1960;de Leon, 1961;Rimoando, 1962;Haramoto, 1969;Nageshchandra and Channabasavanna, 1974a). Of these, Pritchard and Baker (1958) listed 63 host plant genera, and Nageshchandra and Channabasavanna (1974a) listed 35 genera in India alone. Jeppson et al. (1975) listed citrus, tea, coffee, peach, papaya, loquat, coconut, apple, pear, guava, olive, fig, walnut and grape as its principal hosts.


Source: cabi.org
Description


Adult females of P. latus are small (ca 200 µm) and have an unornamented dorsal shield. The prodorsal shield is not enlarged to cover the stigmata. Trichobothria on the prodorsum are capitate. Dorsal idiosomal setae are short. There are four pairs of setae on the dorsum of propodosoma in the male. Tibia and tarsus IV of the male are fused and bear a button-like claw.
Lindquist (1986) provided a detailed description and illustration of this species.

Symptons

P. latus symptoms vary on different plants (Gerson, 1992). Edges of damaged young leaves usually curl. The foliage often becomes rigid and appears bronzed or scorched. Feeding of mites on the under surface of young leaves causes Gerbera to become rigid and rolled under at the edges. As leaves age, they may split, producing a ragged appearance of different shapes. Infested young potato leaves initially have oily black spots on the under surface, which later turn reddish. The plants become rosetted and then die back. Symptoms on red chilli pepper (Capsicum sp.) are similar. On lemons, this species produces multiple buds on citrus seedlings and discoloration on the skin of fruit. Damage on cucumber, aubergines and Solanum laciniatum includes crinkling, cracking, discoloration and malformations similar to those caused by a hormonal weedkiller. When grapevine is attacked, young leaf edges turn downwards, followed by browning and necrosis.
When chilli leaves are attacked, the leaf tissues disintegrate and the epidermal layer of the infested leaves thickens, with both the pallisade and spongy parenchymatous tissues becoming irregular and the cell nuclei enlarged in severely infested leaves (Karmakar, 1997).

Impact


The broad mite P. latus is spread worldwide. In the tropics and subtropics it reproduces the whole year round and has a wide host range. In temperate climates it is a serious pest on vegetables and ornamental plants in glasshouses. Due to its high reproductive potential, it can reach damaging densities within a very short time.


Source: cabi.org
Description

Keifer (1965) first described A. guerreronis. The adult female coconut mite is vermiform, 36-52 µm wide and 205-255 µm long with two pairs of legs and a finely ringed body with several long setae. The genital opening of both sexes is positioned proximally, closely behind the legs.

Recognition


The scarring and distortion of nutlets can be observed from the ground, although with taller trees the use of binoculars may be necessary. Harvested nuts also bear the marks, although few, if any, mites will be found on these.

Symptons


Populations of the mite develop on the meristematic zone of the young nuts, from as early as one month after fertilization. This area is covered by the perianth (collectively, the tepals, and often referred to as the bracts). Feeding of the mites in this zone apparently causes physical damage so that as newly formed tissue expands, the surface becomes necrotic and suberized, usually in distinct 'v' shape(s) extending down from the perianth. Uneven growth results in distortion and stunting of the coconut;usually the younger the nut when first attacked the greater the severity of damage.

Impact


The coconut mite, Aceria guerreronis, is considered the most important pest of coconuts in the Americas, Africa and most recently in South-East Asia. Although its exact origin is debatable it is likely to be native to South America and introduced to Africa and Asia, where it is an invasive species (Navia et al., 2005).

Hosts

A. guerreronis is the only species of eriophyoid mite considered to be a serious pest of coconuts, Cocos nucifera. It was first described in 1965 from specimens from Guerrero State, Mexico (Keifer, 1965). Until reported from Lytocaryum weddellianum, a cocosoid palm species, it was only known from the coconut (Flechtmann, 1989) but has since been reported on Borassus flabellifer and Syagrus romanzoffiana.


Source: cabi.org
Description

A. fulica is distinctive in appearance and is readily identified by its large size and relatively long, narrow, conical shell. Reaching a length of up to 20 cm, the shell is more commonly in the size range 5-10 cm. The colour can be variable but is most commonly light brown, with alternating brown and cream bands on young snails and the upper whorls of larger specimens. The coloration becomes lighter towards the tip of the shell, which is almost white. There are from seven to nine spirally striate whorls with moderately impressed sutures. The shell aperture is ovate-lunate to round-lunate with a sharp, unreflected outer lip. The mantle is dark brown with rubbery skin. There are two pairs of tentacles on the head: a short lower pair and a large upper pair with round eyes situated at the tip. The mouth has a horned mandible, and a radula containing about 142 rows of teeth, with 129 teeth per row (Schotman, 1989;Salgado, 2010). Eggs are spherical to ellipsoidal in shape (4.5-5.5 mm in diameter) and are yellow to cream in colour.

Recognition

A. fulica is a large and conspicuous crop pest which hides during the day. Surveys are best carried out at night using a flashlight. It is easily seen, and attacked plants exhibit extensive rasping and defoliation. Weight of numbers can break the stems of some species. Its presence can also be detected by signs of ribbon-like excrement, and slime trails on plants and buildings.

Symptons

In garden plants and ornamentals of a number of varieties, and vegetables, all stages of development are eaten, leading to severe damage in those species that are most often attacked. However, cuttings and seedlings are the preferred food items, even of plants such as Artocarpus which are not attacked in the mature state. In these plants damage is caused by complete consumption or removal of bark. Young snails up to about 4 months feed almost exclusively on young shoots and succulent leaves. The papaya is one of the main fruits which is seriously damaged by A. fulica, largely as a result of its preference for fallen and decaying fruit.
In plants such as rice, which are not targets of A. fulica, sometimes sheer weight of numbers can result in broken stems. In general, physical destruction to the cover crop results in secondary damage to the main crop, which relies on the cover crop for manure, shade, soil and moisture retention and/or nitrogen restoration. This in turn can result in a reduction in the available nitrogen in the soil and consequently marked erosion in steeper areas.

Impact


The giant African land snail A. fulica is a fast-growing polyphagous plant pest that has been introduced from its native range in East Africa to many parts of the world as a commercial food source (for humans, fish and livestock) and as a novelty pet. It easily becomes attached to any means of transport or machinery at any developmental stage, is able to go into a state of aestivation in cooler conditions and so is readily transportable over distances. Once escaped it has managed to establish itself and reproduce prodigiously in tropical and some temperate locations. As a result, A. fulica has been classified as one of the world's top 100 invasive alien species by The World Conservation Union, IUCN (ISSG, 2003).

Hosts

A. fulica is a polyphagous pest. Its preferred food is decayed vegetation and animal matter, lichens, algae and fungi. However, the potential of the snail as a pest only became apparent after having been introduced around the world into new environments (Rees, 1950). It has been recorded on a large number of plants including most ornamentals, and vegetables and leguminous cover crops may also suffer extensively. The bark of relatively large trees such as citrus, papaya, rubber and cacao is subject to attack. There are reports of A. fulica feeding on hundreds of species of plants (Raut and Ghose, 1984;Raut and Barker, 2002). Thakur (1998) found that vegetables of the genus Brassica were the most preferred food item from a range of various food plants tested. However, the preference for particular plants at a particular locality is dependent primarily on the composition of the plant communities, with respect to both the species present and the age of the plants of the different species (Raut and Barker, 2002). Crops in the Poaceae family (sugarcane, maize, rice) suffer little or no damage from A. fulica.
Given the polyphagous nature of A. fulica any host list is unlikely to be comprehensive. Those plant hosts included in this datasheet have been found in literature searches and Venette and Larson (2004).


Source: cabi.org
Description


Eggs

Recognition


The majority of thrips species are so small and cryptic that, except when present in very large numbers, many inspectors and commercial operators may fail to see them. Adults and larvae are able to hide in concealed places on plants such as beneath plant hairs, within tight buds, enclosed in developing leaves, or underneath the calyx of fruits. Eggs are laid concealed within plant tissues. Casual inspection may thus not reveal the presence of thrips, and even insecticide treatment may be ineffective because the chemical fails to contact the hidden thrips. Effective detection methods have yet to be deployed by most quarantine inspection systems, reliance usually being placed on inspection for feeding damage and simple beating to reveal thrips. However, adult and larval thrips can be extracted from plant material within two or three minutes if a sample is placed in a small Tullgren Funnel using turpentine as an irritant rather than light;the living thrips then run down into a glass tube at the bottom of the funnel where they are readily observed and counted.
Infestation levels in glasshouse crops are usually monitored by means of blue or yellow sticky traps. One shade of blue is particularly attractive to flying adult thrips and is widely used for monitoring the species (Brødsgaard, 1989a). Pheromone lures that attract males and females are now available to increase the sensitivity of monitoring at low levels of infestation or in easily damaged crops (Hamilton et al., 2005). Thrips can also be monitored by extracting thrips from flowers and recording their numbers or the percentage occupancy of flowers (Navas et al., 1994;Steiner and Goodwin, 2005). Western flower thrips adults are easily carried into glasshouses by wind, as well as on the clothes or in the hair of working personnel, thus making re-infestation from surrounding weeds a constant probability. Indeed, weed control around a crop, whether inside a glasshouse or on surrounding land, is the first measure to be adopted in any control strategy. Thrips are also easily carried on equipment and containers that have not been properly cleaned, and infestations in sterile laboratories with filtered air are usually due to thrips being carried in on the clothes and hair of workers. Nationally and internationally, F. occidentalis is readily transported to new areas on all types of planting material as well as on cut flowers, both commercial and domestic (Vierbergen, 1995).

Symptons


The symptoms of infestation by F. occidentalis vary widely among the different plants that are attacked. On roses or gerberas with red flowers, or on dark Saintpaulia flowers, feeding damage is readily visible as white streaking. This type of damage is less apparent on white or yellow flowers, and these commonly tolerate very much higher thrips populations with no visible symptoms. Severe infestation leads to deformation of buds if the feeding occurs before these start opening. Capsicums and cucumbers that have been attacked whilst young, show serious distortions as they mature. Leaf damage is variable, but includes silvering due to necrotic plant cells that have been drained of their contents by thrips feeding, malformation due to uneven growth, and a range of spots and other feeding scars. Eggs laid in petal tissue cause a 'pimpling' effect in flowers such as orchids. Egg laying on sensitive fruits such as table grapes, tomatoes and apples leads to the spotting of the skin of the fruit, which reduces the aesthetic value of the fruit. It can also lead to splitting and subsequent entry of fungi. However, the most serious effect of thrips feeding is due to the transmission of tospoviruses into susceptible crops, such as tomatoes, capsicums, lettuce or Impatiens. At least five different tospoviruses are known to be transmitted by western flower thrips and more may well be discovered: Tomato spotted wilt virus (TSWV), Impatiens necrotic spot virus (INSV), Groundnut ringspot virus (GRSV), Chrysanthemum stem necrosis virus (CSNV) and Tomato chlorotic spot virus (TCSV) (Whitfield et al., 2005). These viruses are acquired by the first-instar or early second-instar larvae when feeding on an infected plant, and are then transmitted only later when these larvae develop into the mobile adults;it is not possible for an adult to acquire and then transmit any of these viruses (Moritz et al., 2004). Virus symptoms vary considerably among plants, ranging from the disastrous wilting and collapse of lettuce plants, through a range of leaf mottling and distortions, to ring-spotting on tomato and capsicum fruits. These virus attacks can lead to the total loss of certain crops (see reviews in Kuo, 1996). F. occidentalis also transmits a carmovirus (Pelargonium flower break virus, PFBV) and may transmit an ilarvirus (Tobacco streak virus, TSV) (Jones, 2005).

Impact


Since the 1970s Frankliniella occidentalis has successfully invaded many countries to become one of the most important agricultural pests of ornamental, vegetable and fruit crops globally. Its invasiveness is largely attributed to the international movement of plant material and insecticide resistance, both of which have combined to foster the rapid spread of the species throughout the world (Kirk and Terry, 2003). Individuals are very small and they reside in concealed places on plants;thus are easily hidden and hard to detect in transported plant material. They reproduce rapidly and are highly polyphagous, breeding on many horticultural crops that are transported around the world.

Hosts

F. occidentalis is a highly polyphagous species with at least 250 plant species from more than 65 families being listed as 'hosts'. Unfortunately, the term 'host plant' is poorly defined in the literature on thrips. Plant species have sometimes been listed as 'hosts' simply because adults have been collected from them. The concept of 'host plant' is best restricted to those plants on which an insect can breed, and for many of the 250 plants from which F. occidentalis has been recorded there is little or no evidence of successful breeding. However, the association of adults with various plants has economic importance when viruliferous adults feed on susceptible plants. In its native range of the western USA, this thrips species can be found in large numbers on a very wide range of native plants, from lowland herbs to alpine shrubs and forbs. As a pest it is found both outdoors and in glasshouses, and it attacks flowers, fruits and leaves of a wide range of cultivated plants. These include apples, apricots, peaches, nectarines and plums, roses, chrysanthemums, carnations, sweet peas, Gladiolus, Impatiens, Gerbera and Ranunculus, peas, tomatoes, capsicums, cucumbers, melons, strawberries, lucerne, grapes and cotton. In northern Europe it is found particularly on glasshouse crops, such as cucumbers, capsicums, chrysanthemums, Gerbera, roses, Saintpaulia and tomatoes. In southern Europe it is extremely damaging to many field crops, including capsicums, tomatoes, strawberries, table grapes and artichokes, and at least in southern Italy, it has become a dominant member of the thrips fauna in wild flowers. Similarly, in Kenya the species has become a dominant member of the wild thrips fauna near agricultural fields. In contrast, in Australia it has not been found breeding on any native plant species. A further complication in considering its pest status is that in some areas this thrips species is an important predator of plant-feeding mites, such as on cotton in California, and it is then regarded as a beneficial (Trichilo and Leigh, 1986).


Source: cabi.org
Description


Although somewhat variable in size and coloration, adult specimens of H. halys range from 12 to 17 mm in length, and in humeral width of 7 to 10 mm. The common name brown marmorated stink bug is a reference to its generally brownish and marbled or mottled dorsal coloration, with dense punctation. Detailed redescriptions and diagnoses of adults are provided by Hoebeke and Carter (2003) and Wyniger and Kment (2010). Eggs are smooth and pale in colour, approximately 1.3 mm in diameter by 1.6 mm in length, and are laid in clusters of 20-30. The brightly coloured, black and reddish-orange first instars remain clustered about the egg mass after hatching and move away once moulting to second instars has occurred. There are five nymphal instars, which are described in Hoebeke and Carter (2003) with a key and illustrated with colour photos.

Recognition

H. halys adults can be detected throughout the active growing season using blacklight traps and baited pheromone traps and nymphal populations can be detected with pheromone traps. However, each trap has limitations. Blacklight traps are attractive from early spring through September with reduced attractiveness as adults begin seeking overwintering sites. Baited pheromone trap effectiveness depends on the lure deployed. The use of methyl (2 E,4 E,6 Z)-decatrienoate only provides late season adult attractivess, whereas the use of (3 S,6 S,7 R,10 S)-10,11-epoxy-1-bisabolen-3-ol and (3 R,6 S,7 R,10 S)-10,11-epoxy-1-bisabolen-3-ol alone or in combination with methyl (2 E,4 E,6 Z)-decatrienoate provides season-long adult attractiveness.
In cropping systems, H. halys adults and nymphs can be detected through the use of timed visual counts, whole plant inspections, beat sheets counts and sweep netting. Timed visual counts are effective in field maize, nursery, nut, tree fruit and vegetable crops. Whole plant inspections are possible in various vegetables, field and sweetcorn by inspecting a specified number of plants per field or through the use of counts per linear foot of row. Beat sheet counts can be employed in nursery, nut and tree fruit;however, they are discouraged in nuts and tree fruit after thinning or June drop has occurred due to the potential removal of fruit. Sweep netting can be used in soyabeans but should be confined to field borders.
H. halys adults seek concealed, cool, tight and dry locations to overwinter. Because of this overwintering behaviour and need for specific microhabitats, many suitable sites can be generated by human-made materials and used by this insect as an overwintering sites such as inside cardboard boxes, other shipping containers and luggage, between wooden boards, within layers of folded tarps, and within machinery motors and vehicles. Thus, inspection for H. halys in shipments of goods from areas where it is present will require thorough visual inspections.

Symptons


Adults and nymphs cause feeding damage. On tree fruits, feeding injury causes depressed or sunken areas that may become 'cat-faced' as the fruit develops. Late season injury causes corky spots on the fruit. Feeding may also cause fruiting structures to abort prematurely. Similar damage occurs in fruiting vegetables such as tomatoes and peppers, although frequently later in the season. Feeding can cause failure of seeds to develop in crops such as maize or soyabean. There is frequently a distinct edge effect in crop plots as H. halys has an aggregated dispersion and moves between crops or woodlots. In soyabeans, this can result in a 'stay green' effect where pods fail to senesce at the edges due to H. halys feeding injury.

Impact


Following the accidental introduction and initial discovery of H. halys in Allentown, Pennsylvania, USA, this species has been detected in 41 states and the District of Columbia in the USA. Isolated populations also exist in Switzerland, France, Italy and Canada. Recent detections also have been reported in Germany and Liechtenstein. BMSB has become a major nuisance pest in the mid-Atlantic region and Pacific Northwest, USA, due to its overwintering behaviour of entering human-made structures in large numbers. BMSB also feeds on numerous tree fruits, vegetables, field crops, ornamental plants, and native vegetation in its native and invaded ranges. In the mid-Atlantic region, serious crop losses have been reported for apples, peaches, sweetcorn, peppers, tomatoes and row crops such as field maize and soyabeans since 2010. Crop damage has also been detected in other states recently including Oregon, Ohio, New York, North Carolina and Tennessee.

Hosts

H. halys has over 100 reported host plants. It is widely considered to be an arboreal species and can frequently be found among woodlots. Such host plants are important for development as well as supporting populations, particularly during the initial spread into a region. In Canada for example, established populations of H. halys have only been recorded in the Province of Ontario. Homeowner finds have previously been identified in the City of Hamilton (Fogain and Graff, 2011) as well as the Greater Toronto Area, the City of Windsor, Newboro and Cedar Springs (Ontario) (Fraser and Gariepy, unpublished data). However, preliminary surveys confirmed an established breeding population in Hamilton, Ontario, as of July 2012 (Fraser and Gariepy, unpublished data). At present, these populations are localized along the top of the Niagara escarpment in urban/natural habitats within Hamilton, and have not yet been recorded in agricultural crops. Reproductive hosts from which H. halys eggs, nymphs and adults have been collected on in Ontario include: ash, buckthorn, catalpa, choke cherry, crabapple, dogwood, high bush cranberry, honeysuckle, lilac, linden, Manitoba maple, mulberry, rose, tree of heaven, walnut and wild grape (Gariepy et al., unpublished data).
The list of host plants in Europe contains 51 species in 32 families, including many exotic and native plants. High densities of nymphs and adults were observed on Catalpa bignonioides, Sorbus aucuparia, Cornus sanguinea, Fraxinus excelsior and Parthenocissus quinquefolia (Haye et al., unpublished data).
Multiple host plants seem to be important for development and survival of H. halys. This species can complete its development entirely on paulownia (Paulownia tomentosa), tree of heaven (Ailanthus altissima), English holly and peach. More details on host plants and host plant utilization can be found at http://www.stopbmsb.org/where-is-bmsb/host-plants/ as well as http://www.halyomorphahalys.com, Panizzi (1997), Nielsen and Hamilton (2009b) and Lee et al. (2013a).
In Asia, H. halys is an occasional outbreak pest of tree fruit (Funayama, 2002). Damage to apples and pears in the USA was first detected in Allentown, Pennsylvania, and Pittstown, New Jersey (Nielsen and Hamilton, 2009a). In orchards where H. halys is established in the USA, it quickly becomes the predominant stink bug species and, unlike native stink bugs, is a season-long pest of tree fruit (Nielsen and Hamilton, 2009a;Leskey et al., 2012a). In particular, peaches, nectarines, apples and Asian pears are heavily attacked. Feeding injury causes depressed or sunken areas that may become cat-faced as fruit develops. Late season injury causes corky spots on the fruit. Feeding may also cause fruiting structures to abort prematurely. Similar damage occurs in fruiting vegetables such as tomatoes and peppers, although frequently later in the season. Feeding can cause failure of seeds to develop in crops such as maize or soyabean. There is frequently a distinct edge effect in crop plots as H. halys an aggregated dispersion and moves between crops or woodlots. In soyabeans, this can result in a 'stay green' effect where pods fail to senesce at the edges due to H. halys feeding injury.


Source: cabi.org
Description

H. vitripennis is a large insect (about 13 mm). It is generally brown to black but the underside of the abdomen is whitish. The upper aspect of the head and thorax is brown or black with numerous ivory to yellowish spots. These spots allow H. vitripennis to be easily distinguished from its close relative, the native Californian smoke tree sharpshooter (Homalodisca lacerta), which has pale, wavy lines instead of the spots. The sausage-shaped eggs are laid side-by-side in masses averaging 10 to 11 eggs. The egg masses appear as greenish water blisters beneath the leaf. They are elongate, with the individual eggs running transversely across the mass. The nymphs are dark grey (first and second stage) to grey (third to fifth stage). The cast skin from the final nymphal moult to the adult often adheres to the stem or leaf surface (Phillips, 1998).

Recognition

Yellow sticky traps are commonly used for surveillance and detection. Colour preferences for attraction to H. vitripennis are not well known, but it will fly to yellow. On warm nights it is attracted to black and incandescent lights. Active stages may be found by searching plant stems. Fresh egg masses are found on the underside of recently matured foliage (older foliage should be avoided). Active stages can be easily detected by placing a tarpaulin under the suspected host plant, at temperatures below 15°C, and striking the plant vigorously. A sweep net placed over the foliage can be used in a similar manner (Phillips, 1999a;Varela et al., 2001).

Symptons

H. vitripennis is a stem feeder and leaves no visible symptoms of its feeding other than a white, powdery, dried excrement on plant surfaces.
Feeding causes no visible signs of damage, even though the insect consumes hundreds of times its body weight per day in xylem fluid. Most non-xylem-feeding leafhoppers produce a sugary or particulate excrement, but the excrement of xylem feeders is watery, high in ammonia and dries to a fine, whitish powder which can cover the stems, foliage and fruit when the insects are abundant (Phillips, 1998). High densities of feeding sharpshooters excrete enough waste product to cause a 'rain', which falls from the trees;this rain can easily be seen on sunny days and can be felt on the skin. This phenomenon is particularly acute in Tahiti where puddles form on roads and side walks as result of sharpshooter rain.
Egg masses are usually laid into recently expanded foliage. Older foliage will contain the distinctive scars left after the eggs have hatched. When populations are more abundant, egg masses can be laid into the rind of immature fruits of crops such as citrus and melon. Old hatched egg masses appear as grey or tan scars on surface of the rind (Blua et al., 1999).

Hosts

As H. vitripennis continues to expand is range within California following its accidental introduction (ca 1989), both the ovipositional and feeding host lists continue to expand, primarily within ornamental plant species grown in nurseries or landscape gardens. As it is a xylem feeder, it circumvents secondary plant defence chemistry found in phloem sap and, as a result, it appears to be able to feed on most plant species. The high volume of xylem fluid intake required limits its survival to situations in which continued contact with a living host is possible. Only the egg stage is capable of survival for 2 or 3 weeks on excised plant foliage as long as it is kept fresh and moist.
H. vitripennis attacks plants in the following families: Aceraceae, Agavaceae, Amaranthaceae, Anacardiaceae, Apocynaceae, Aquifoliaceae, Araceae, Araliaceae, Asclepiadaceae, Asteraceae, Begoniaceae, Berberidaceae, Betulaceae, Bignoniaceae, Buxaceae, Caesalpiniaceae, Caprifoliaceae, Caprifoliaceae, Casuarinaceae, Celastraceae, Chenopodiaceae, Clusiaceae, Combretaceae, Convolvulaceae, Cupressaceae, Cycadaceae, Eleagnaceae, Ericeae, Euphorbiaceae, Fabaceae, Ginkoceae, Graminaceae, Hamamelidaceae, Iridaceae, Juglandaceae, Lamiaceae, Lauraceae, Liliaceae, Logaiaceae, Lythraceae, Magnoliaceae, Malvaceae, Meliaceae, Moraceae, Myoporaceae, Myrtaceae, Nyctaginaceae, Nyssaceae, Oleaceae, Onagaaraceae, Phytolaccaceae, Pinaceae, Pittospaceae, Platanaceae, Poaceae, Podocarpaceae, Polypodaceae, Proteaceae, Rosaceae, Rubiaceae, Rutaceae, Salicaceae, Sapindaceae, Sapotaceae, Saxifragaceae, Theaceae, Ulmaceae and Vitaceae.
H. vitripennis is native to the subtropical gulf states of south-eastern USA, in areas with a high water table where wild hosts produce the luxuriant growth necessary to sustain this prodigious xylem feeder. Its native range also includes the more arid regions of southern Texas and north-eastern Mexico, especially irrigated habitats such as landscape gardens and citrus orchards. After the recent introduction and spread of H. vitripennis in California, it has become extremely abundant on citrus and several ornamental and native plant species in southern parts of the state (Sorensen and Gill, 1996). Despite originating in a humid, subtropical region H. vitripennis can become abundant in Mediterranean climates if plants receive adequate irrigation and winter temperatures are not to severe.


Source: cabi.org
Description

Adult
The adult is greyish brown with a 9-mm-long body and a wingspan of about 12-15 mm (Anonymous, 1983;Reid and Cuthbert, 1971). In males, upper (costal) two-thirds of forewings is light fuscous, sometimes partially ochre-tinged;sometimes mixed with whitish scales, and flecked with scanty small blackish dots. Lower one-third of the forewings is ochreous-white, the upper edge being nearly white, margined broadly with dark brown or black-brown. In females, the upper two-thirds of forewing is light ochreous or light grey-ochreous, the contrast not so pronounced between upper and lower portions in coloration, but the markings are like those of males. When wings are folded, three or four diamond-shaped areas formed by forewings are visible on the dorsal side when moth is at rest, hence the common name 'diamondback moth'. Moriuti (1986) gives details of wing venation and genitalia. The moths are weak fliers and can disperse, on average, only 13-35 m within a crop field (Mo JianHua et al., 2003). They are readily carried by the wind and can travel long distances, at 400-500 km per night (Chapman et al., 2002).
Egg

Recognition


Colour: when disturbed, tiny adults fly from plant to plant. When at rest, three or four diamond-shaped areas formed by two forewings, are visible on the dorsal surface. Pale-green larvae with pale green to brown head capsules or brown pupae covered in white silken cocoons are present on plant parts damaged by P. xylostella.
Size: adult 10-12 mm long, fully-grown larva 10 mm long, pupa 5-6 mm long.
Behaviour: adults fly when disturbed. Larvae curl up when disturbed, or drop from the foliage to the ground.
Traps: adults are attracted to light traps. Adult males are attracted to sex pheromone which consists of three chemicals: (Z)-11-hexadecenal, (Z)-11-hexadecenyl acetate and (Z)-11-hexadecenyl alcohol (Chow et al., 1978). The yellow sticky traps can also be used to monitor populations in the field (Sivapragasam and Saito, 1986).
Food: Major host plants associated with the family Cruciferae with a few host plants in the family Capparidaceae (Idris, 1998;Tanaka et al., 1999).
Scouting Techniques in Oilseed rape
The count method, although often laborious, is currently the most accurate method of estimating P. xylostella population densities in oilseed rape. It involves performing counts of larvae in several locations throughout the field and determining the average population per unit area. Remove plants in an area of 0.1 m 2, beat them onto a clean surface, and count the number of larvae dislodged from the plants. Scout at least five locations per field and monitor crops at least twice weekly (Canola Council of Canada, 2014).
The action threshold in Canadian oilseed rape crops is 20-30 larvae/0.1 m 2 at the advanced pod stage. This works out to approximately two to three larvae/plant, given the plant population is about 100 plants/m 2 (Canola Council of Canada, 2014).
Sweep net sampling and trapping (e.g. sticky, pheromone and bowl traps) can be used to detect the presence and general abundance of P. xylostella in the field, but these tools alone may not provide a reliable estimate of larval density. Nevertheless, high counts in sweep sampling and trapping can prompt growers to use the more accurate 'count method' (Sarfraz et al., 2010;Canola Council of Canada, 2014).
In regions such as Canada where P. xylostella infestations are associated with annual migrations, pheromone traps coupled with wind trajectory models are useful tools to determine the size and timing of the moth flight.
Scouting Technique in Brassica Vegetables
In Brassica vegetable crops, the 'percent infested' threshold scouting technique is more efficient in detecting damaging pest populations as it avoids the need to remove plants and count pests and is relatively easy for growers to use (Berry, 2000). This technique is successfully used to scout several other insect and mite pests in commercial crops.
Various types of traps (e.g. sticky, pheromone, pitfall and bowl traps) can also be used to detect the presence and relative abundance of P. xylostella in the field.

Symptons


The insect larva is a surface feeder and with its chewing mouthparts it feeds voraciously on the leaves leaving a papery epidermis intact. This type of damage gives the appearance of transluscent windows or 'shot holes' in the leaf blades. Insect larvae and, in many cases, pupae are found on the damaged leaves. In cases of severe infestation, entire leaves could be lost, leaving only the veins. The larvae nibble the chlorophyll-rich green areas of stems and pods and the damage shows from a distance as an unusual whitening of the crop. The damage is often first evident on plants growing on ridges and knolls in the field (Canola Council of Canada, 2014). Heavily damaged plants appear stunted and in most cases die.
In oilseed rape plants, larvae also feed on flower buds, flowers and young seed pods. The seeds within damaged pods do not fill completely and pods may shatter prematurely. Larvae also chew into pods and consume the developing seeds. Extensive feeding on the reproductive plant parts significantly reduces crop yields (Canola Council of Canada, 2014).

Impact

The diamondback moth (DBM) is one of the most studied insect pests in the world, yet it is among the 'leaders' of the most difficult pests to control. It was the first crop insect reported to develop resistance to microbial Bacillus thuringiensis insecticides, and has shown resistance to almost every insecticide, including the most recent groups such as diamide. DBM is a highly invasive species. It may have its origin in Europe, South Africa or East Asia, but is now present wherever its cruciferous hosts exist and is considered to be the most universally distributed Lepidoptera. It is highly migratory and wind-borne adults can travel long distances to invade crops in other regions, countries and continents. Immature stages also hitchhike on plant parts and can establish in new areas. DBM costs the global economy an estimated US$4 -5 billion annually, but its impacts on local biodiversity and habitats in exotic ranges are unknown.

Hosts

The natural host plant range of P. xylostella is limited to Brassicaceae which are characterized by having glucosinolates, sulfur-containing secondary plant compounds. Glucosinolates may be toxic to generalist insects, but DBM is known to rely on some of them for host location, oviposition and herbivory. Certain glucosinolates, cardenolides, plant volatiles, waxes, as well as host plant nutritional quality, leaf morphology and leaf colour, or a combination of these factors, may trigger reproductive and feeding activities of DBM (Sarfraz et al., 2006 and references therein).
Cruciferous weeds serve as alternate hosts (Sarfraz et al., 2011). For instance, the wind-borne moths can arrive in parts of the oilseed rape growing areas in Canada from the southern USA early enough that many of the rape crops will not have emerged yet (Canola Ccouncil of Canada, 2014). In these situations cruciferous weeds become important alternate 'bridge' hosts.
Some populations have also been found to infest non-cruciferous plants (see List of Hosts). However, host plant shift from feeding on crucifers to feeding on non-crucifers may depend on geographical populations. For example, a Kenyan population of P. xylostella adapted to sugar snap peas (Löhr and Gathu, 2002) whereas a Canadian population, despite of multiple attempts, could not survive on peas in the laboratory (Sarfraz, unpublished data).
For further information on hosts, see Sarfraz et al. (2006, 2010, 2011) and references therein, and Sakakibara and Takashino (2004).


Source: cabi.org
Description

A. hispidus is sometimes considered to be perennial, as in Bhutan where it is described as ‘usually perennial’ (Noltie, 2000), but it is more commonly described as annual. It is a sprawling plant, rooting at the nodes with flowering stems up to 30 cm high;nodes hairy. Leaves are relatively short and broad, narrowly obovate up to 5 cm long and 15 mm wide, auricled at the base and acutely tipped, variably glabrous or hairy on the margins. Ligule 0.5-3 mm. Inflorescence a set of up to 10 or more racemes, up to 5 cm long, pale green or purple, variously glabrous to shortly hairy. Sessile spikelet up to 7 mm long;lower glume lanceolate, convex, 6-9-nerved with scabrid veins. Upper glume slightly longer with awn up to 11 mm long in typical forms but may be much shorter and hardly exserted. Pedicelled spikelet occasionally present at the tip of the raceme, but usually absent with pedicel a stump up to 2 mm long. Anthers 2, about 1 mm long.

Impact

A. hispidus is a sprawling grass, native to East and Southern Asia, and Africa. It has been widely introduced across North and Central America and the Caribbean, and was first recorded in the USA in the 1870s. In West Virginia and in Maryland, USA, A. hispidus is seen as a potential competitor to the endangered species Ptilimnium nodosum;Over the past decade, this aggressive grass has become widespread in many parts of the state (W. Virginia). As an annual it can compete directly…. for occupation of ephemeral habitat;without control, A. hispidus could overrun and locally extirpate P. nodosum. ’ (US Fish and Wildlife Service, 1990;1998). It is listed as an invasive weed in a number of other states of USA, such as Kentucky (Louisville Water Company, 2013). Although widespread as a weed elsewhere, it has not otherwise been described as invasive, while in Australia it is itself treated as a threatened species (Australia, 2013).

Hosts

A. hispidus occurs in tea fields, orchards, grasslands and gardens, but no serious damage has been recorded. It is a weed of direct-seeded, dry-sown rice in Korea (Ku et al., 1993).


Source: cabi.org
Description


Primarily from Clayton et al. (2014) and Cowie et al. (2000), with minor additions from Florida collections:
Habit

Recognition


Diagnostic features of the genus Hymenachne include its aquatic habit and lower internodes filled with spongy aerenchyma, the cylindrical inflorescence, the margins of the upper lemma being flat and the glumes not saccate (Webster, 1987). In Australia, the genus is ultimately characterized from other Panicae by the first glume which encircles the spikelet base (Webster, 1987).
Commodity inspectors should be wary of contamination in rice seed, especially rice grown in Central and South America or Louisiana, USA. Inspectors should look for the spikelets, which are light in colour, flattened, and only a few millimetres long;the actual seed/fruit (caryopsis) is too small to detect with the unaided eye.
A trained botanist having intact, mature spikelets may find them possible to identify using the illustration provided (see Images, above) and the following characters:
1) Lower glume wrapping the base of the spikelet and small, appearing only 1.3 as long as the spikelet and wedge shaped at the tip, 3-5 nerved and scabrous on the keel.
2) Lower lemma 3.6-4.6 mm, 5 nerved and tapering gradually to a long point, longer than the fruit, margins flat, and scabrous on the nerves.
3) Upper glume 2.8-3.9 mm long, 5 nerved and scabrous on the nerves.
Vegetative material may be less likely to be transported, but is easier to recognize. Use the illustration above to focus on:
1) Leaf blade flat with base auriculate and clasping
2) Leaf glabrous except for the base having a few long hairs
3) Stems solid
4) Nodes with adventitious, spongey roots

Impact

H. amplexicaulis is a perennial, stoloniferous, freshwater grass that forms monospecific stands in seasonally flooded environments of tropical, subtropical, and warm temperate climates. It is native to Central and South America, where populations have increased around human disturbance. H. amplexicaulis has been introduced to the USA and Australia, where both countries first observed its invasive abilities in the 1990s. Robust, long lived, tolerant to hydrological fluctuation, and able to spread locally by fragments and across distances by seed, H. amplexicaulis is capable of displacing native species and altering indigenous communities under natural regimes. It is known to hinder irrigation, drainage and hydroelectric systems in agricultural and urbanized systems. It has also corrupted indigenous genotypes by hybridizing with a native Australian congener to form the morphologically intermediate hybrid H. x calamitosa. H. amplexicaulis was ranked by the Florida Exotic Pest Plant Council as a Category I invasive due to the ecological damage it has caused. In Australia, it is prohibited as a Class 2 Declared Pest and named a Weed of National Significance for its proven potential to invade wet areas across a wide geographic range.

Biological Control
<br>An effective biological control agent has not been determined for H. amplexicaulis, although studies have been made.<br>The sap-feeding bug Ischnodemus variegatus, discovered on H. amplexicaulis in Florida, has been found to reduce the plant’s growth rate and biomass (Overholt et al., 2004). I. variegatus is predicted to complete three to five generations per year in areas where its host plant has invaded Florida (Diaz et al., 2008). Laboratory studies found that it developed and survived best on H. amplexicaulis (23.4% survival) than on other genera tested (Diaz et al., 2009) and that it performed poorly overall on H. acutigluma when compared to H. amplexicaulis (Diaz et al., 2010).<br>An undescribed Delphacidae species found naturally occurring on H. acutigluma in Australia did not occur nearby on H. amplexicaulis and did not develop on H. amplexicaulis in laboratory tests. The insect species proved to be host specific to H. acutigluma, causing yellowing and weakening of that species under high densities in the laboratory (Bell et al., 2011).

Source: cabi.org
Description


The most thorough description available is by Hayes et al. (2012), in which P. canaliculata and P. maculata are compared. The following brief description is modified from that publication.

Recognition


The most recognizable sign of the presence of P. canaliculata (and other related apple snail species) is their bright-pink egg masses, which are laid on emergent vegetation (including wetland crops) and other hard surfaces above the water line, such as rocks, logs and bridge supports (Hayes et al., 2009b). These egg masses are very noticeable and can even be seen from a moving vehicle.

Symptons


In wetland rice the first symptom of damage by P. canaliculata is a reduced plant stand where the snails have severed the plant stalks below the water level. The tillers are cut first and then the leaves and stems are consumed under water. The crop is highly vulnerable at the early seedling stage. In taro, damage to the corms is readily visible, and active snails are easily seen feeding on both corms and leaves that have drooped so that their tips break the water surface.

Impact

P. canaliculata is a freshwater snail native to parts of Argentina and Uruguay. The distribution of P. canaliculata has been steadily increasing since its introduction to Asia, primarily as a human food resource but perhaps also by the aquarium trade, beginning around 1979 or 1980 (Mochida, 1991;Halwart, 1994a;Cowie, 2002;Joshi and Sebastian, 2006). Once introduced to an area, it spreads rapidly through bodies of water such as canals and rivers and during floods. It feeds on aquatic plants and can devastate rice (in South-east Asia), taro (in Hawaii) and other aquatic or semi-aquatic crops. It may out-compete native apple snails (Halwart, 1994a;Warren, 1997), prey on native fauna (Wood et al., 2005, 2006) and alter natural ecosystem function (Carlsson et al. 2004a). It is also an important vector of various parasites including the nematode Angiostrongyulus cantonensis, which causes human eosinophillic meningitis (Lv et al., 2011;Yang et al., 2013).

Hosts


The list of crops and other plants affected is not an exclusive list of all wild plant species potentially affected. P. canaliculata is primarily a generalist macrophyte herbivore and determining what plants it does not eat may be more important than generating a long list of plants it will eat (Cowie, 2002).
Regarding the most important crop affected, rice, it is the young seedling stage that is most vulnerable (Halwart, 1994a;Okuma et al., 1994b;Schnorbach, 1995;Naylor, 1996;Cowie, 2002;Wada, 2004). All parts of wetland taro plants are eaten because the snails can access the leaves when they droop down to the water surface.
Because of its generalist feeding habits, P. canaliculata has been suggested as a biological control agent for aquatic and wetland weeds in rivers (Cazzaniga and Estebenet, 1985;Fernández et al., 1987) and rice fields (Okuma et al., 1994b;Wada, 1997;Joshi et al., 2006). It can be used to control weeds without eating the rice plants only if rice seedlings are transplanted and at the 3-leaf stage (21 days), so that they are too tough for the snails to eat, and the ground is allowed to dry until water is introduced to a 2 cm depth after 6-8 days after transplanting (Joshi et al., 2006).

Biological Control
None of the predators of apple snails in their native ranges have been shown to play a significant role in snail population regulation, although snail kites may be important in this regard (R.H. Cowie, personal observations). In South-east Asia, various fish, birds, rats, lizards, frogs, toads, beetles and ants are known to feed on introduced apple snails or their eggs (Halwart, 1994a). Some of these, especially rats, also cause serious damage to rice, and introduction or promotion of others as biocontrol agents may have unknown environmental consequences. Only ducks and fish have attracted any serious consideration as potential control agents.<br>Rice farmers often breed ducks and herd them into rice fields to eat the snails in the period before transplanting (Cowie, 2002;Wada, 2004). A similar approach has been taken for taro in Hawaii (Levin, 2006;Levin et al., 2006). Various duck varieties have been used (Teo, 2001;Levin, 2006;Levin et al., 2006). Two to four ducks per 100 m² were effective in controlling young snails (Vega 1991;Pantua et al., 1992;Rosales and Sagun, 1997;Cagauan, 1999), but some farmers reject this practice because duck faeces contain fluke cercariae that penetrate the skin, which results in itchiness or paddy-field dermatitis (Cagauan and Joshi, 2003). A density of 5-10 ducks per ha in continuous grazing for a period of 1-2 months significantly reduces the pest density from 5 snails per m² to 1 snail per m² (Cagauan, 1999). As ducks graze on and otherwise damage young rice seedlings, it is appropriate to release the ducks when the transplanted seedlings are 4 weeks old. For direct-sown rice, a longer waiting period of 6 weeks is necessary. Using ducks for control may be more effective against P. canaliculata than using chemical molluscicides because the chemicals become ineffective either due to poor drainage in the plots or because snails are still buried in the soil (Cruz and Joshi, 2001).<br>Fish have also been suggested as biological control (Rondon and Sumangil, 1989;Morallo-Rejesus et al., 1990), but few quantified studies have been undertaken (Cagauan and Joshi, 2003). Cyprinus carpio (common carp) and Oreochromis niloticus (Nile tilapia) are popular species for controlling P. canaliculata, with the former more effective than the latter in removing snails (Halwart, 1994b). C. carpio crack the snail's shell, ingest the soft tissue and spit out the broken shell;thus they can feed on snails up to 12 mm high. In contrast, O. niloticus ingests the whole shell, and can therefore only feed on snails smaller than 3 mm. In Japan, black or Chinese carp (Mylopharyagodon piceus) and C. carpio fingerlings have been released to feed on newly hatched snails (Mochida et al., 1991). Models predicting predation rates are provided by Yusa et al. (2001), Ichinose and Tochihara (2001) and Ichinose et al. (2002). One of the problems with using fish is that the water must be kept deep enough for them, which may not be compatible with other methods (Wada, 2004).<br>Little is known of microorganisms associated with ampullariids that might be useful in control, nor of parasitoids that attack either the snails or their eggs. In the Philippines, twelve bacterial isolates were tested, seven of which were effective against P. canaliculata (Cowie, 2002).<br>Halwart (1994a) recommended that specific natural enemies for P. canaliculata, such as the predatory Sciomyzidae, should be sought in its native home in South America.<br>All deliberate introductions of non-indigenous species, including as biological control agents, should be carefully evaluated prior to introduction in terms of both their positive and negative potential impacts, and monitored after introduction.

Source: cabi.org
Description

C. aspersum is a large-sized land snail, with a shell generally globular but sometimes more conical (higher spired) and rather thin in the common form when compared to other Helicinae. The umbilicus is usually completely closed by a thickened white reflected lip that defines the peristome in adult snails. The shell is sculptured with fine wrinkles and rather coarse and regular growth-ridges and is moderately glossy because of a fine periostracum. The peristome is roundly lunate to ovate-lunate. Adult shells (4½ to 5 slightly convex whorls) measure 28-45 mm in diameter, 25-35 mm in height (Kerney and Cameron, 1979). The shell ground colour is from yellowish to pale brown. The shell also shows from zero to five reddish brown to blackish spiral bands superimposed on the ground colour and usually interrupted such that the ground colour appears as yellow flecks or streaks breaking up the bands;the bands are occasionally separated by a median white spiral line (fascia albata). Fusion of two or more adjacent bands and diffusion of band pigment on the whole shell surface are often observed. Frequently, the upper half of the shell is darker because of the effect of a dominant factor (Albuquerque de Matos, 1985). The banding pattern is much less distinct and more broken than that exhibited by the well-known polymorphic snails Cepaea nemoralis and Cepaea hortensis.

Recognition


The following information is from the Canadian Food Inspection Agency Cornu aspersum fact sheet (CFIA, 2014).
Indications of an attack by C. aspersum are ragged holes chewed in leaves, with large veins usually remaining;holes in fruit;and slime trails and excrement on plant material.
Adults and larger juveniles are likely to be visible among the host material or attached to the transporting containers. They may also be hidden in protected locations, sealed into their shells to avoid desiccation. Check the undersides of containers and their rims. Small snails and eggs in soil could be difficult to find. C. aspersum hides in crevices and will overwinter in stony ground.
Inspections are best carried out under wet, warm and dark conditions. Under bright, dry conditions it is necessary to thoroughly search dark, sheltered areas where the humidity is elevated, such as under low-growing plants or debris. The snails may bury themselves in loose soil or other matter, so the only way to be reasonably sure an area is not infested is to make repeated surveys over a long period of time.

Symptons

C. aspersum causes extensive damage in orchards (creating holes in fruit and leaves) and to vegetable crops, garden flowers and cereals.
In California, USA, populations established in citrus groves feed essentially on the foliage of young citrus and also on ripe fruits, creating small holes allowing the entry of fungi and decay of the fruit (see Pictures). Larger holes result in fruit dropping from the tree or being rejected for consumption during sorting and packing (Reuther et al., 1989;Sakovich, 2002).
In South African viticultural regions, C. aspersum feeds essentially on the developing foliar buds and young leaves of the vines. In kiwifruit vineyards (California, New Zealand), damage occurs on the flowers, not the fully developed fruit, since snails consume only the sepal tissue around the receptacle area. Damage to the sepals can be detrimental by increasing the development of the fungus Botrytis cinerea during cold storage of fruits, and moreover, the slime trail mucus stimulates germination of B. cinerea conidia (Michailides and Elmer, 2000).

Impact

C. aspersum, the common garden snail, is represented by several forms that are highly differentiated genetically. Only one lineage, the western one, is considered to be invasive in regions where it has been introduced recently (since the sixteenth century) either accidentally or intentionally (e.g. North and South America, South Africa, Oceania). It was in California, USA, where it was introduced in the 1850s, that it was first treated (1931) as a regulated pest. Its success in colonizing new areas after introduction and establishment may be due to: (i) large phenotypic variation in combinations of life-history traits, especially reflecting a high degree of plasticity (e.g. trade-off of egg weight/egg number), and (ii) great resistance against natural enemies. Also, genetic data indicate that C. aspersum is capable of establishing even after a severe genetic bottleneck.

Hosts

C. aspersum is a polyphagous grazer with a large diet spectrum. In its natural habitat, it feeds on wild plants such as Urtica dioica or Hedera helix, which are also used for shelter. In human-disturbed habitats, a wide range of crops and ornamental plants are reported as hosts: these include vegetables, cereals, flowers and shrubs (Godan, 1983;Dekle and Fasulo, 2001). In particular, it causes serious damage in citrus groves and vineyards. It will feed on both living and dead or senescent plant material. The Host Plants/Plants Affected table does not cover all plants that C. aspersum will feed on, as the list is so extensive but aims to provide an insight to the well-known species affected. The categorization as 'Main', 'Other' or 'Wild host' is also subjective and should not be considered definitive.

Biological Control
<br>As terrestrial molluscs have many natural enemies, there has been strong interest in the biological control of C. aspersum using other, predatory snails (e.g. Fisher and Orth, 1985). However, as most of these predatory snails are not host-specific, they are not appropriate to use in control programmes in which effects on non-target species are of concern (Cowie, 2001: Barker and Watts, 2002).<br>There have been several attempts to develop biological control of C. aspersum in California, South Africa and New Zealand, which began with the introduction of predaceous snails (Euglandina rosea, Gonaxis sp.) and beetles during the 1950s and early 1960s (for more information see Fisher and Orth, 1985;Barker and Efford, 2004). These efforts were largely unsuccessful, although one staphylinid beetle (Staphylinus (Ocypus) olens) showed potential;however, the use of this species as a biological control in orchards has not been actively pursued (Sakovich, 2002). In 1966, however, another (opportunistic) predaceous snail, the decollate snail Rumina decollata (of European origin) was found to have invaded California (see Pictures). Experimental releases of R. decollata in southern California citrus orchards were begun in 1975 and, in most cases, resulted in complete control (displacement) of C. aspersum (Fisher and Orth, 1985). Rumina decollata is now used to control C. aspersum in some 20,000 ha of citrus in southern California, but is currently permitted only in certain Californian counties (Dreistadt et al., 2004). As this predatory snail consumes young to half-grown snails, control is achieved only in 4-6 years. Sakovich (2002) recommended first using molluscicidal baits to reduce the population, and then combining skirt-pruning and copper barriers with introduction of R. decollata. Once control by R. decollata is achieved, maintenance of copper barriers can cease, R. decollata can be harvested and transferred to new areas. However, Cowie (2001) expressed concern regarding both the effectiveness of R. decollata in control of C. aspersum, its potential impacts on native (even endangered) species and its potential as a garden plant pest.<br>A study by Altieri et al. (1982) was carried out in a daisy field in northern California to determine the effectiveness of the indigenous coleopterous predator Scaphinotus striatopunctatus in the biological control of C. aspersum. Release of the predator in the field under light metal sheets, together with colonization by garter snakes (Thamnophis elegans) from an adjacent field, resulted in a significant reduction in snail populations.<br>In South Africa, the native predacious gastropod Natalina cafra was investigated as a potential biological control agent against C. aspersum, with special attention to the possibility of establishing a viable population of the natural enemy in captivity (Joubert, 1993), but this approach seems not to have been implemented.<br>Research by the Entomology Division of the Plant Protection Department, Cukurova University, Turkey, on the importation of predators and parasitoids as biological control agents (mainly for citrus pests) included the coccinellid Hippodamia convergens as a potential predator of C. aspersum (Uygun and Sekeroglu, 1987).<br>Ducks, chickens or guinea fowl can provide long-term control in citrus orchards and vineyards, if an appropriate breed is chosen and properly cared for. Growers take the animals each morning into the orchard for as little as half an hour to scavenge for food. This solution can be very effective but involves extra labour in managing the animals and protecting them from predators (Sakovich, 2002;Davis et al., 2004).

Source: cabi.org
Damage Theba pisana
Title: Theba pisana
Description

The following is taken in part and modified from Kerney and Cameron (1979), Cain (1984) and Cowie (1984a). More detail is provided by Taylor (1906-1914). Adult shell up to 20 mm high and 25 mm wide, though rarely this big and more normally around 15-18 mm wide. Shell slightly depressed globular (wider than high), with 5½-6 slightly convex whorls with shallow sutures. Umbilicus narrow, and partly obscured by reflected columellar lip. Mouth of adult shell elliptical, with an internal thickening (no outwardly reflected lip) and sometimes a pinkish flush. Juvenile shell with a sharp keel at the periphery (mid-line of the shell), becoming rounded as the shell grows to adulthood. Shell sculpture of growth-ridges crossed by fine spiral striations. Shell white or off-white, rarely pink, either plain or with spiral patterning of lines (translucent, pale yellowish, dark brown or blackish), which may be broken transversely into dots and dashes, augmented with feathering along their edges, or fused to varying extents producing arrow-head shapes, chevrons and blocks. Patterning may only appear on later whorls.

Recognition

Detection is straightforward. Adult snails are normally 15-18 mm in width and readily seen, especially as they tend to rest or aestivate on the plants above the ground during the day and in hot conditions. Juveniles are smaller but are also quite readily seen. Usually population densities are high, making the snails even more readily visible. Detection and inspection is by visual searching. Searching should be focussed on plants, fences, and other vertical surfaces on which the snails rest exposed well above the ground surface, especially in sandy areas. Shipping materials (crates, pallets, containers) coming from areas where the snails are known to exist should be examined. Although generally readily visible, nooks and crannies in containers and shipping materials and cargo should be carefully searched.

Symptons

Damage is by external feeding and most, if not all above ground parts of the plants are susceptible, perhaps with the exception of bark of well established trees. In most cases the symptoms are obvious – external damage to the plant. Also, the snails congregate on the affected plants in large numbers;their copious slime trails may be especially visible;and, when they leave their resting/aestivation sites on the plants, the remaining dry, white, calcareous epiphragms that they used to seal themselves to the plants may be visible.

Impact

T. pisana is a medium-sized snail with a sub-globular, generally white or off-white shell that often bears a complex pattern of darker markings. It is generally a species of coastal habitats with warm to hot and arid climates, although it extends into cooler and wetter habitats in northwest Europe. Its range includes almost all the Mediterranean coastline, extending up the Atlantic coast of Europe. The extent to which this range is natural is not certain. Morocco has been suggested as its region of origin. Beyond this European/Mediterranean range, the major regions to which it has been introduced are South Africa (first recorded 1881), Australia (1890s) and California (1914), in all three regions rapidly becoming an invasive pest. It is frequently intercepted by quarantine officials both associated with shipments of goods and in personal luggage, indicating that it is both accidentally and deliberately transported over long distances. It is also readily transported relatively short distances, for instance attached to vehicles. Once introduced, its high rate of growth and reproduction and ability to reach extremely high population densities make it a potentially serious and difficult to control pest. It is listed as a potential pest of quarantine significance in the United States.


Source: cabi.org
Title: Theba pisana
Description


The live adult female is 2.9-5.0 mm long and 2.4-4.0 mm wide, with a pale yellow oval body covered in white wax or sulfur-yellow flocculent wax tinged with white. In the slide-mounted adult female, the antennae each have 9-11 segments and there are three pairs of abdominal spiracles towards the apex of the abdomen. The center of the abdominal venter becomes invaginated to form a marsupium into which the vulva opens, and there is a marsupial band of simple multilocular pores along the lip of the marsupium, which becomes sclerotized with age.

Recognition


Foliage and stems should be inspected for lumps of white or yellow wax secreted by scale insects, symptoms of pest attack, attendent ants, sticky honeydew and sooty mould growth on leaves. A user-friendly, online tool has been produced for use at US ports-of-entry to help with the identification of potentially invasive scale insect species (Miller et al., 2014a,b).

Symptons


Most damage to plants is caused by the early immature stages of I. samarai, which feed on the leaf undersides, settling in rows along the midrib and veins, and on smaller twigs. The older nymphs feed on larger twigs, and as adults they settle on larger branches and the trunk. Damage to plants results from phloem sap depletion during feeding, leading to shoots drying up and dying. Trees that are badly attacked suffer partial defoliation and a general loss of vigour. The insects dischargesugary honeydew, which can be copious in large colonies and may foul plant surfaces. Besides direct damage by feeding, indirect damage can result from the development of black sooty mould on the honeydew on leaf surfaces, blocking light and air from the plant, leading to a reduction in photosynthesis (Beardsley, 1955).

Impact


The scale insect Icerya samaraia (formerly Steatococcus samaraius) occurs in the Australasian, Oriental and Oceanic zoogeographic regions. It has a wide host range which includes mostly woody plant species in 40 genera belonging to 25 families. It is a minor pest of citrus, banana, coconut, guava, papaya, cocoa, pigeon pea and other plants, including forest and ornamental trees. Populations of I. samaraia are apparently being kept under control on the Palau Islands in the western Pacific Ocean by natural enemies, particularly by the introduced coccinellid Rodolia pumila. I. samaraia can be transported on infested plant materials because of its small size and habit of feeding in concealed areas, making it a potential threat as an invasive species.

Hosts

I. samaraia has been reported on mostly woody plant species in 40 genera belonging to 25 families from the Australasian and Oriental zoogeographic regions (Miller et al., 2014a).

Biological Control
<br>The coccinellid predator Rodolia pumila is believed to be specific to Icerya species and closely related scale insects, and has been used successfully for the biological control of the related species Icerya aegyptiaca on some islands of Micronesia (Schreiner, 1989;Waterhouse, 1993).<br>Of three species of Rodolia (R. pumila, R. cardinalis and R. breviuscula) introduced to the oceanic Pacific for the control of I. aegyptiaca, I. purchasi and I. seychellarum, only R. pumila became widely established on the high islands of Micronesia by the 1950s. R. pumila appears to have been less successful on low coral atolls, possibly after reducing the abundance of its hosts to such low levels that the coccinellid was unsustainable (Beardsley, 1955;Schreiner, 1989;Waterhouse, 1993). This leads to a boom and bust cycle, with predatory beetles disappearing for long enough in some locations for damaging populations of I. aegyptiaca to develop for several years at a time (Waterhouse, 1993). R. pumila is also reported to keep populations of I. samaraia under control in Palau (Beardsley, 1966).<br>Another coccinellid, Cryptolaemus montrouzieri, was introduced for the control of Icerya spp. in Palau and Saipan (Northern Mariana Islands) and became established by 1940 (Schreiner, 1989;Waterhouse, 1993). It has been recorded attacking I. samaraia in Palau (Beardsley, 1955).

Source: cabi.org
Description


Pneumostome located on the right-hand side of the mantle and near the front margin;keel absent;mantle granular. Foot fringe broad, heavily lineolated, similar in colour to that of the back. Juveniles have dark lateral bands with paler ‘shadow’ bands on the sides above these – compare juvenile Arion rufus and juvenile and adult Arion subfuscus. Sides below the bands are pale. Colour is variable - yellowish, greyish, chocolate, reddish, brownish (never greenish). The adults are normally unbanded, colour of the upper surface a uniform yellowish-brown, brown, reddish-brown or dark-brown, rarely black. Eggs are white, slightly transparent, soft-shelled, ca 2 mm in diameter.

Recognition


The occurrence of A. vulgaris in transported plant materials may involve the adults, juveniles or eggs.
The adults and juveniles are active after dark and may be detected in the evening or early morning, or by inspecting plant materials stored under cover. Like Deroceras reticulatum, all stages hide in leaf whorls, under debris, stones and wood and occasionally in the soil around root systems.
The eggs are deposited on the soil, under dead leaves or other surface debris and are not buried in the soil.
Traps containing molluscicides (metaldehyde, carbamate, iron pyrophosphate hydrate) may be used to collect material, but hand collecting is often just as efficient and avoids the risk of contaminating produce.

Symptons


Copious deposits of slime and slime trails leading from damaged site indicate activity.
Damage only within 1-5 m from the field edge, next to an area with dense, undisturbed vegetation, for example, grassland, fallow, scrub and garden.
Surface damage to large plants or plant parts specifically indicates the presence of this species. Complete removal of plants may occur.
No damage occurs below ground with this species.

Impact


The invasiveness of A. vulgaris is related to several factors. Its ability and readiness to colonize humanly-disturbed environments is of major importance. Proschwitz (1997) observed that 99% of Swedish records were from synanthropic habitats and only 1% from natural woodlands. With a proximity to humans, comes the possibility of passive dispersal through trade, particularly in living plants. The garden centre trade and horticulture are particularly implicated (Weidema, 2006). In Poland, there is evidence from studies of molecular diversity that A. vulgaris has originated from repeated, separate introductions from other parts of Europe (Soroka et al., 2007).

Hosts

A. vulgaris is a serious pest of diverse vegetable crops (especially Brassicaceae, lettuce, cucurbits), vegetable seedlings, arable crops (Triticaceae), ornamental plants, low-growing fruits (strawberries) and herbs within gardens in Central Europe, regularly causing severe losses. In the early stages of arable crop development (after seedling emergence or after planting), the plants are seriously defoliated or completely destroyed. The leaves, flowers or fruit may be damaged with feeding holes, and the potential harvest devalued. In Austria, serious damage to arable agriculture has been reported (Reischütz, 1984). In Poland, A. vulgaris was found to feed on a wide range of plants, including arable crops and commonly occurring weeds. Slug damage was found on 103 plant species (including wild species) and preferred crops including Brassica napus (Kozlowski and Kaluski, 2004;Kozlowski, 2005).


Source: cabi.org
Description


Detailed descriptions and illustrations of F. auricularia are provided by Crumb et al. (1941), Behura (1956), and Lamb and Wellington (1975).

Recognition

F. auricularia is primarily a nocturnal species, hiding during daytime in dark places, where it tends to aggregate. Its presence in the agricultural environment can easily be established by looking under loose bark, stones, pots, wooden boards etc., or by providing artificial hiding places such as upturned flower pots filled with straw or cardboard. Using corrugated cardboard rolls or bands on trunks of trees or grapevines is an easy way to detect earwigs in orchards and vineyards. They can be easily seen on crop edges and on trees and vines when active and feeding at night (Department of Agriculture and Food, Government of Western Australia, 2015).
Despite the considerable size of last instars and adults detection is difficult in shipments. With vegetables, a sample will need to be cut open in order to reveal any hiding earwigs. Sometimes submergence of fruits and vegetables (e.g. cauliflowers) in cold water will drive earwigs out. Frequently they hide in the cores of apples and pears, in which case their presence can often be detected through frass and some external damage around the remnants of the calyx through which they usually enter the inside..
It is also difficult to detect contamination with earwigs in bulk loads, timber and balled up or potted plants.

Symptons

F. auricularia is a polyphagous generalist feeding on a wide range of crops, particularly fruits, vegetables and flowers. Most of the damage observed is caused by external feeding, resulting in partially destroyed or shredded plant parts. Feeding on tender plant parts often results in underdeveloped or malformed crops. On hops, earwigs have been observed to feed on young tender leaves (Theobald 1896). In corn (Zea mays) they feed on tender kernels but greater damage is caused by feeding on the silks, which leads to underdeveloped grains (Crumb et al., 1941). Sugar beets and mangels are damaged by feeding on both the roots and leaves (Lind et al., 1914, Lind et al., 1916). Cabbage varieties such as Savoy or cauliflower are prone to be affected by earwigs through direct feeding on the leaves, tunneling into the cabbage heads, and hiding and feeding inside. Other crops reported to be affected are peas, beans and tomatoes (Capinera, 2013). Occasionally, defoliation of potato plants takes place (Frank, 1896). Serious damage to seedlings is reported from cabbage, carrot and cucumber (Crumb et al., 1941). In flower production earwigs cause damage by feeding on various parts of the plants. Seedlings and flower buds are particularly affected, resulting in deformed blossoms (Crumb et al., 1941). There have been reports of earwigs damaging flowers of fruit trees such as plums (Theobald, 1896). In New Zealand, earwigs have been of economic concern by eating into peaches, nectarines and apricots rendering them useless for sale and in Chile damage to ripening cherries is problematic (Tillyard, 1925;Devotto et al., 2014). In Australia cherries are particularly affected;earwigs either eat directly into ripe fruits or damage the stalks of ripening cherries (Department of Agriculture and Food, Government of Western Australia, 2015. Damage to ripe apples and pears is sometimes reported (Capinera, 2013).

Impact


The European earwig, Forficula auricularia, is a polyphagous insect that is native to large parts of Europe and western Asia as far east as western Siberia. In the early twentieth century it was accidentally introduced into North America where it became widespread in a number of states/provinces of both the USA and Canada. It has also invaded Australia and New Zealand, and more recently Mexico, Chile and the Falkland Islands. Although economic damage to vegetable and flower gardens is generally minor, when high population densities occur it is a major pest in gardens and greenhouses, and a significant nuisance in households. Within and sometimes also outside its native range it is also regarded as a beneficial organism used or encouraged as a biological control agent to control other insect pests in orchards and gardens.

Hosts

F. auricularia is extremely polyphagous and has been reported to cause damage on a wide range of crops, in particular vegetables, flowers and stone fruits. Damage is mainly caused by external feeding of late instars and adults. Vegetables are mostly affected by external feeding externally on leaves, stems and stalks, and sometimes by penetrating the inside of crops such as cabbages and cauliflowers or feeding on seedlings and young plants (Frank, 1896;Lind et al., 1914, Lind et al., 1916;Crumb et al., 1941;Baker, 2009;Weems and Skelley, 2010;Department of Agriculture and Food, Government of Western Australia, 2015). In addition a wide variety of fruits can be affected by earwigs, with damage to stone fruits such as cherries, nectarines, peaches and apricots being more prevalent compared to apples and pears (Theobald, 1896;Tillyard, 1925;Crumb et al., 1941;Department of Agriculture and Food, Government of Western Australia, 2015).
In vineyards damage is caused by feeding on tender leaves, shoots and fruits (Huth et al. 2009;Department of Agriculture and Food, Government of Western Australia, 2015). The biggest problem with F. auricularia in vineyards is, however, their presence in harvested berries and the risk of tainting wine (Department of Agriculture and Food, Government of Western Australia, 2015).
The species can cause significant damage to flower production with dahlias, pinks, carnations, sweet William, zinnias and roses most frequently cited (Crumb et al., 1941;Weems and Skelley, 2010). Hops can be affected by feeding on tender leaves and shoots (Theobald, 1896). Among staple crops, damage has been reported from potatoes and corn (Frank, 1896;Coyne, 1928;Hearle, 1929;Eckstein, 1931;Weems and Skelley, 2010).

Biological Control
<br>The tachinid flies Triarthria setipennis and Ocytata pallipes are the two main parasitoids of F. auricularia in its native range. T. setipennis is generally the more abundant species, causing significantly higher infection rates. However, O. pallipes sometimes can exert high rates of parasitism;it seems to be better adapted to coastal climates and may in regions with maritime climates be equally suited for the control of F. auricularia (Phillips, 1983;Kuhlmann et al., 2001). Both species have been released repeatedly into the USA, Canada and New Zealand (Atwell, 1927;Davies, 1927;Crumb et al, 1941;Evans, 1952;Kuhlmann et al., 2001). Only T. setipennis is known to have established and spread to large areas of the USA and Canada (Dimick and Mote, 1934;McLeod, 1954;O’ Hara, 1996;Kuhlmann et al., 2001).<br>An intensive breeding and release program of T. setipennis originating from the Mediterranean region started in 1924 and lasted until the 1930s in Portland, Oregon, where it became well established (Dimick and Mote, 1934;Spencer, 1945). Since then, it has also established in Washington, California, Idaho, Utah, New Hampshire and Massachusetts (O’ Hara, 1996). It was also released in Connecticut and Rhode Island but has not been recovered there (O’ Hara, 1994).<br>In Canada, releases of T. setipennis were made in British Columbia (1934–1939), Ontario (1930–1941) and Newfoundland (1951–1953) using flies originating from Oregon (Getzendaner, 1937;McLeod, 1962). The species established in British Columbia and Newfoundland but did not reach high population densities (Mote, 1931;Dimick and Mote, 1934;Spencer, 1947), possibly due to poor adaptation to local climatic conditions (Kuhlmann et al., 2001). Additional releases of the species collected from climatically better matching sites in Switzerland, Germany and Sweden were made in the 1960s. New introductions into Newfoundland were followed by an average increase in parasitism (Morris, 1971, 1984;Morry et al., 1988), but in Nova Scotia, no establishment of T. setipennis could be confirmed (Kuhlmann et al., 2001). Five additional attempts were made in the 1980s to establish T. setipennis in the Ottawa area but it is not known whether it has established (Kuhlmann et al., 2001). The early studies on the establishment of T. setipennis in Newfoundland indicated a considerable reduction in earwig numbers, which was most probably due to high levels of parasitism in the mid-1970s (Morris, 1984;Kuhlmann et al., 2001). Since 1978, no further evaluation of parasitoid impact has been undertaken (Kuhlmann et al., 2001).<br>During the 1930s, some O. pallipes adults were released but only established temporarily in Oregon (Mote, 1931;Clausen, 1978). Pupariae of this species were also shipped to New Zealand for release there but whether the fly became established is not known (Davies, 1927;Evans, 1952). T. setipennis and O. pallipes have also been assessed for their suitability and safety to control F. auricularia on the Falkland Islands and both species are part of an on-going release programme (Maczey et al., 2016).<br>Details of the biology of T. setipennis and O. pallipes are provided by Thompson (1928), Mote et al. (1931), and Kuhlmann (1994, 1995).<br>Apart from the above-mentioned studies in Newfoundland, little information is available on how much effect these natural enemies have on earwig populations.

Source: cabi.org
Description


The colonies of C. formosanus contain three primary castes: the reproductives, soldiers, and workers. The majority of the nestmates are workers that are responsible for the acquisition of nutrients, i.e. cellulose in the wood. The head width of the white soft-bodied worker is approximately 1.2-1.3 mm and the body length is approximately 4-5 mm. The thorax is narrower than head width. The alates and soldiers are most useful for identification. The alates are yellowish-brown and 12-15 mm long. There are numerous small hairs on the wings of these comparatively large swarmers. The alates are attracted to lights, so they are usually found near windows, light fixtures, windowsills and spider webs, around well-lit areas. The soldiers are approximately the same size as the workers and have an orange-brown oval-shaped head, curved mandibles and a whitish body. When disturbed, the soldiers readily attack any approaching objects and may secrete a white gluey defensive secretion from the frontal gland. There are more soldiers (10-15%) in a C. formosanus colony than in a subterranean termite colony, such as Reticulitermes spp. (1-2%).

Recognition


Occasionally the foraging tubes may be observed on the wood surface or tree trunk. During the swarming season (April to June), elongated mud tubes that serve as flight exit slits may be seen. The damage by C. formosanus tends to occur in places with high moisture including the bathroom, kitchen sinks and leaky roofs. An acoustic emission device (AED) may be used to locate sites with feeding activity, but most AEDs have a limited detection range (Scheffrahn et al., 1993).

Symptons


Large colonies of C. formosanus generally live underground. When these termites invade a house aboveground, the foraging tubes of approximately 0.5-1 cm in diameter may be found connecting the soil and the infested house. In severe infestations, C. formosanus hollows out the wood leaving a paper-thin surface and the hollowed wood surface may look blistered or peeled. Another characteristic of C. formosanus is carton nest material that is made from termite faeces, chewed wood and soil. The honeycomb-like carton nests can be as large as 1-1.5 m in diameter and are usually found in structure-voids such as between walls and beneath sinks.

Impact

C. formosanus is often transported by boats and shipping containers to port cities before being carried further inland via landscape materials such as railroad ties (railway sleepers). This may explain the current C. formosanus distribution in the USA with coastal areas more densely infested than inland areas (Hochmair and Scheffrahn, 2010). Temperature and humidity are primary factors affecting the establishment of C. formosanus, and it is potentially invasive to areas of high humidity approximately 35° north and south of the equator (Su and Tamashiro, 1987). Competition from native species is another limiting factor for many exotic pests, but C. formosanus is more aggressive and is known to out-compete the endemic termites such as Reticulitermes species. Another factor that has allowed the successful establishment and spread of C. formosanus in exotic areas has been the pest control industry's heavy reliance on soil termiticide barriers for subterranean termite control since the 1950s. Numerous studies, using mark-recapture methods, have revealed that a single colony of C. formosanus might contain several million termites that forage up to 100 m in the soil (Lai, 1977;Su and Scheffrahn, 1988). These agree with the results of excavation studies for C. formosanus colonies (Ehrhorn, 1934;King and Spink, 1969). Because of the large colony size, the application of soil termiticides beneath a structure does not usually have a major impact on the overall population, and the surviving colony continues to produce alates that can further infest nearby areas. Once established, C. formosanus has never been completely eradicated from an area. The dependency of soil termiticide barriers as the primary tool for subterranean termite control is probably the main reason for the establishment and spread of C. formosanus from four isolated port cities in the 1960s in the USA to all south-eastern states by 2001.

Hosts

C. formosanus is an opportunistic feeder of any material containing cellulose. A large number of living plants are known to be attacked by C. formosanus, but it usually does not kill the plants unless the root system is significantly damaged (Lai et al., 1983;La Fage, 1987). Records show that living citrus, eucalyptus and sugar canes (Saccharum sp.) may be killed by C. formosanus, but in most cases damage occurs in the heartwood of a tree. The infested trees may be more easily blown over by high winds due to the loss of structural strength. The pest status of C. formosanus is most significant when it attacks wood products in a house such as structural lumbers, cabinets, etc. C. formosanus is also known to damage non-cellulose materials in search of food, including plastic, concrete and soft metal. Occasionally underground high-voltage power lines may be penetrated by C. formosanus, resulting in an area-wide power cut.


Source: cabi.org
Description

According to Koganezawa and Sakuma (1984), the morphology of the fungus is identical to that of Botryosphaeria dothidea. The sizes of the ascoma, asci and ascospores are variable. Asci are 80-130 x 14-23 µm, and ascospores are 19-26 µm long. The conidia, of the Fusicoccum anamorph, are 23-29 x 6-8 µm. In China, conidia of 10 isolates measured 20.0-31.5 x 4.5-7.0 µm (Lee and Yang, 1984).

Symptons

On Japanese pears [ Pyrus pyrifolia ] (Kato, 1973) and apples [ Malus ] in China (Lee and Yang, 1984), the fungus forms wart-like protuberances (wart bark) on the surface of trunks and branches, rather than typical Botryosphaeria cankers. These are subsequently surrounded by dark-brown spots. Infected twigs eventually wither and die back. Large contoured dark-brown spots are formed on the leaves and the fruits. The warts on trunks and branches damage the tree, reducing its growth and productivity. The leaf spots are of minor importance and do not affect yield.


Source: cabi.org
Damage Uraba lugens
Title: Uraba lugens
Description

The small hairy larvae of U. lugens feed gregariously on the upper and lower epidermis, the pallisade tissue and the spongy mesophyll of the leaf but avoid the oil cells and the veins. This feeding habit results in the leaf being ‘skeletonised’, hence the common name of the insect. Larger larvae, from the fifth instar, feed individually and consume the entire leaf blade down to the mid-rib (Cobbinah, 1978). From around the fifth instar, U. lugens larvae retain their moulted head capsules on top of their head, creating a distinctive ‘head dress’. Larvae spin a camouflaged pupal cocoon incorporating their own hairs and fragments of surrounding materials. Adult moths are approximately 10 mm in length with a wingspan of 25 to 30 mm. The forewings are dark grey with several dark wavy lines connecting front and rear wing margins (Anonymous, 1979). The hindwings are pale grey-brown.

Recognition

U. lugens can be detected by searching leaves. Eggs are laid in batches on the leaf surface, and young larvae feed gregariously adjacent to the egg batch after emergence. Oviposition tends to occur mainly in the lower crow of the tree (Morgan and Cobbinah, 1977). Young larvae skeletonise the leaves, making leaf damage easy to detect. Skeletonised leaves often have characteristic patches of cast skins where larvae have moulted before moving on. After the fifth instar larvae disperse and can be found singly, often in the vicinity of abandoned skeletonised leaves. When close to pupation, larvae wander in search of a suitable site. Camouflaged cocoons are formed in the bark or leaf litter and are very difficult to find. A synthetic pheromone has been developed, and can be used for detection and delimiting surveys (Suckling et al., 2005).

Symptons

Early instar larvae skeletonise leaves, which then turn brown, giving the tree a scorched look when damage is heavy. Older larvae feed on the entire leaf blade down to the midrib, which can resemble defoliation.

Impact

U. lugens was first considered a serious pest of natural eucalypt forests in Western Australia in 1983 when the first severe outbreak occurred there (Strelein, 1988). Prior to that it was widely known as a pest of eucalypt forests in eastern Australia (Campbell, 1962;Harris, 1974). As these natural forests are or were managed for timber production, it is considered an economically important pest in its native range. Damage to amenity trees is also a common problem, although few trees are killed by this defoliation (Anonymous, 1979).

Hosts

Morgan and Cobbinah (1977) list 149 Eucalyptus species and one Angophora species found to be oviposition hosts, out of more than 250 species surveyed in a field study in Adelaide, South Australia. Not all of the oviposition hosts proved to be suitable larval hosts. That work was part of a wider study in which over 580 tree species were surveyed (Cobbinah, 1978). Significant defoliation events have occurred in natural forests of Eucalyptus camaldulensis, E. calophylla and E. marginata in mainland Australia (Campbell, 1962;Strelein, 1988;Farr, 2002), and in plantations of E. nitens in Tasmania (Anonymous, 1994) although damage is common on a wide range of eucalypt species. E. nitens and E. fastigata are important commercial plantation and farm forestry species in New Zealand, although commercial impacts of U. lugens on these species have yet to be felt. The iconic native species Metrosideros excelsa (pohutukawa) has been recorded as a host in New Zealand, although this seems to only occur through spill-over feeding from near by eucalypts (Potter at al., 2004) and is not significantly impacting these trees. A number of other new host records have occurred in New Zealand since U. lugens arrived in that country, most notably on a range of deciduous Northern Hemisphere species. The most significant damage on these species has occurred on Betula pendula (silver birch), where some trees have been defoliated (J Bain, Scion, Rotorua, New Zealand, personal communication, 2008).
In New Zealand, U. lugens has been recorded on 58 tree species (J Bain, Scion, Rotorua, New Zealand, personal communication, 2008), mainly from the genus Eucalyptus. It is causing significant damage in New Zealand on Lophestemon confertus, which is commonly planted as a street tree in some parts of Auckland. In a laboratory study of larval suitability of 18 highly valued eucalypt species in New Zealand, Potter and Stephens (2005) found E. nitens, E. nicholii and E. fastigata were most at risk.


Source: cabi.org
Title: Uraba lugens
Description


A comprehensive description of the plant is given by Pfitzenmeyer (1962)

Impact


False oat-grass, Arrhenatherum elatius, is a tall, usually erect, tussock-forming, perennial grass. It is sensitive to low temperatures and prefers neutral soils of high to moderate fertility. The species is native and widespread throughout most parts of Europe, western and southwestern Asia, and North Africa. Within its native range the species is often abundant in lightly grazed or mown grasslands, particularly hay meadows, or along roadside verges. It is however, absent or rare in pastures or other heavily grazed or trampled grasslands.

Hosts

A. elatius subsp. bulbosum is frequently considered a weed in arable crops (e.g. Langer and Hill, 1991). However, little information is available on the crop species affected and the degree of damage and yield losses caused. In Chile A. elatius is of particular significance in wheat (Ormeño and Díaz, 1995).


Source: cabi.org
Description

C. biflorus is a loosely tufted, annual grass, with ascending stems (culms) up to 1 m tall. Leaves alternate, simple and entire;ligule a line of hairs;blade linear, flat, 2–25(–35) cm × 2–7(–10) mm, apex filiform. Inflorescence a spike-like panicle 2–15 cm × 9–12 mm, with 1–3 spikelets enclosed by an involucre of prickly bristles;rachis angular, sinuous;involucre ovoid, 4–11 mm long with numerous spines, inner spines erect, fused at base, retrorsely hairy on the pungent, recurving apex, outer spines shorter, spreading. Spikelet lanceolate 3.5–6 mm long, acute, consisting of two glumes and usually two florets;glumes shorter than spikelet;lower floret male or sterile, its lemma as long as spikelet, membranous, upper floret bisexual, its lemma as long as spikelet, thinly leathery;stamens three, ovary superior, glabrous, with two hairy stigmas. Fruit a dorsally compressed caryopsis (grain), 2–2.5 mm × 1.5–2 mm (PROTA, 2015).

Impact

C. biflorus is an annual grass native throughout tropical Africa into Pakistan and India. It has been introduced outside of its native range into southern Africa, North America and Australia. C. biflorus is used as a forage and famine crop but more recently it has been recognised as an invasive species. The retrorsely barbed bristles are readily spread in animal fur and can seriously reduce the value of animal hides, while the barbs can damage the mouths of grazing animals. In addition to this, it is possible for this species to dominate disturbed areas and suppress the growth of native biodiversity. C. biflorus is reported as an agricultural weed in a number of countries including Niger, Nigeria, Saudi Arabia and Senegal.

Hosts

C. biflorus occurs as a weed in a wide range of crops, including Pennisetum glaucum (pearl millet) (Munde et al., 2012), Hibiscus sabdariffa (roselle) (El-Naim and Ahmed, 2010) and species of Sesamum indicum (sesame) (Chandawat, 2004).


Source: cabi.org
Description

Clayton et al. (2006) describes V. bromoides as the following

Impact


Weedy annual grasses like V. bromoides can reduce biodiversity on native grasslands, impede their restoration, and alter ecosystem processes. In pastures, V. bromoides reduces productivity, has low palatability, and its seeds can damage hides and wool of grazing animals. In annual crops like wheat, the species reduces yields (ISSG, 2012).

Hosts


In Canada, V. bromoides is one of several species named as threatening the habitat and therefore the survival of Rosy Owl-clover (Orthocarpus bracteosus) (Fairburns, 2002).


Source: cabi.org
Description


The following description is from Brooks and Clemants (2000): A rhizomatous, perennial herb (graminoid), typically growing in dense clumps 20 – 60 cm tall. Rhizomes 2--3 mm diam. Culms erect, 2--6 mm diam. Cataphylls 0 or 1--2, straw-colored, apex narrowly acute. Leaves: basal 1--3, cauline 2--6, straw-colored;auricles absent;blade 2--25 cm x 1.5--6 mm. Inflorescences panicles or racemes of 2--50 heads or heads solitary, 2--14 cm, erect or ascending branches;primary bract erect;heads 3--70-flowered, obovoid to globose, 7--11 mm diam. Flowers: tepals green to brown or reddish brown, lanceolate;outer tepals 2.7--3.6(--4) mm, apex acuminate;inner tepals 2.2--3(--3.5) mm, nearly equal, apex acuminate;stamens 3 or 6;anthers ½ to equal filament length. Capsules included to slightly exserted, chestnut to dark brown, 1-locular, oblong, 2.4--4.3 mm, apex obtuse proximal to beak. Seeds elliptic to obovate, 0.4--1 mm, occasionally tailed.

Recognition

J. ensifolius is a low-statured plant that would be difficult to detect remotely, although ditchlines and areas with wet soil and shallow standing water that can be identified from images should be targeted in surveys. It can be readily identified visually by its combination of flattened leaves and dark, globular seedheads. Similar species can be readily distinguished as described in the ‘Similarities to Other Species’ section.

Impact

Juncus ensifolius is a mostly pioneering or ruderal species of rush that readily establishes in disturbed wet soils, often from buried seeds. Within its native range in western North America it is widespread and infrequent to common, typically a minor, secondary or at most co-dominant species in natural wetlands. Limited reports suggest that it behaves similarly in east Asia (Tachibana et al., 2001), where it is also native. Although it is recognized as having “potential for weediness” (Marr and Trull, 2002), it is not generally viewed as an aggressive invader within its native range and is widely used in wetland restoration and as a landscape plant. There are no published studies documenting its rate of growth, spread or dispersal.

Hosts


There is no evidence that J. ensifolius currently causes significant economic damage to any crop plants, although it apparently occurs as a minor contaminant in grass seed mixes (Piirainen, 2004) or commercial peat (Kirschner, 2002). It is recorded as a competitor of seven endangered species in Hawaii – see the 'Host Plants/Plants Affected' and 'Threatened Species’ tables for more information.

Biological Control
<br>Although J. ensifolius has a number of natural enemies (see ‘Natural Enemies’ section), there are no reports of their use for biological control.

Source: cabi.org
Description


Annual or very rarely biennial, herbaceous, from a stout taproot;stems 15-200 cm tall, erect, glabrous to sparsely tomentose, narrowly and discontinuously winged, the wings spinose, tomentose, branched above the lower third, branches erect to ascending. Basal leaves 6-15 cm long, oblanceolate, deeply 4-10-lobed, the base tapered;cauline leaves alternate, decurrent, sinuate to pinnately lobed, margins spinose, upper surfaces loosely tomentose, becoming glabrous, lower surfaces densely tomentose. Heads discoid (all corollas radial and salverform), 17-22 mm long, 10-20 mm wide, cylindrical to subcylindrical, sessile to stalked, solitary or 2-5 in terminal clusters. Outer phyllaries ovate-lanceolate, loosely tomentose, margins membranous, apices acuminate, terminating in a straight spine;inner phyllaries narrower, scarious. Corollas 10-14 mm long, pink to rose-purple, sometimes white. Achenes 4-6 mm long, tan to brown, sometimes shiny, transversely wrinkled, tubercled above;pappus 10-20 mm long, composed of flat, minutely barbed, white bristles. (Description slightly modified from Wilken and Hannah, 1998).

Impact

Carduus pycnocephalus is a thistle that is native to the Mediterranean region and some other countries further north or east. It has been introduced, presumably accidentally, to the USA, Australia, New Zealand and some other countries in Europe, Asia, Africa and South America. In many of the countries where it has become naturalized it is regarded as a legally-defined noxious plant or pest plant, depending on the current terminology;it also causes problems in some countries where it is considered a native species. It can form dense infestations in some places where it can smother other, smaller plants and, where it occurs in grazed pastures, can limit the access of livestock and also cause them physical damage, as well as contaminating wool. In this way it has become a problem in the USA, Australia, New Zealand, Pakistan, Iran and Europe (Pitcher and Russo, 1988).

Hosts


Pasture species can be replaced, their growth inhibited and accessibility to grazing livestock obstructed by high populations of C. pycnocephalus rosettes and flowering plants (Kelly and Popay, 1985).

Biological Control
<br>According to Picher and Russo (1988) all major parts of C. pycnocephalus are damaged by one or more insect species in southern Europe, whereas in southern California the thistles are relatively free of insect damage. The seed head weevil Rhinocyllus conicus [or Curculio conicus ] has been introduced into several countries (Canada, USA, Australia, New Zealand) for control of one or more thistle species, including C. pycnocephalus. The larvae feed on the receptacle and developing achenes of thistle species and certainly destroy many seeds, but often enough survive to maintain populations of thistles (Popay et al., 1984;Pitcher and Russo, 1988). A crown weevil (Trichosirocalus horridus [or Ceutorhynchus horridus ]) has also been introduced to several countries as a biocontrol agent for thistle species and may be effective against C. pycnocephalus.<br>The fungal rust Puccinia cardui-pycnocephali [ P. calcitrapae ], already present in many countries where C. pycnocephalus or C. tenuifolius or both are present, has also been considered as a possible biocontrol agent, but its effects seem less than lethal although more virulent strains may be more damaging (Olivieri, 1984).

Source: cabi.org
Description


Recent molecular analysis has shown that Acanthaster planci is in fact a species complex consisting of four distinct clades from the Red Sea, the Pacific, the Northern and the Southern Indian Ocean. Benzie (1999) had previously demonstrated the genetic differentiation between A. planci from the Pacific and the Indian Ocean, and this genetic grouping is reflected in the distribution of colour morphs: grey-green to red-brown in the Pacific Ocean, and blue to pale red in the Indian Ocean (Benzie, 1999). Colour combinations can vary from purplish-blue with red tipped spines to green with yellow-tipped spines (Moran, 1997). Those on the Great Barrier Reef are normally brown or reddish grey with red-tipped spines, while those in Thailand are a brilliant purple (Moran, 1997). Adult A. planci usually range in diameter from around 20 to 30cm (PERSGA/ GEF 2003) although specimens of up to 60cm (and even 80cm) in total diameter have been collected (Chesher, 1969;Moran, 1997). The juvenile starfish begins with 5 arms and develops into an adult with an astounding 16 to 20 arms, all heavily armed with poisonous spines 4 to 5cm in length, which can inflict painful wounds (Moran, 1997;Birk, 1979). Arm values vary between localities with a range of 14 to 18cm given for the Great Barrier Reef (Moran 1997). Starfish are usually concealed during daylight hours, hiding in crevices (Brikeland and Lucas, 1990;Chesher, 1969). Groups of starfish often move as huge masses of 20 to 200 individuals, presenting a terrifying "front" which destroys the reef as it moves through (Chesher, 1969). Signs of starfish presence are obvious;the coral skeleton is left behind as the result of starfish feeding and stands out sharply as patches of pure white, which eventually become overgrown with algae (Chesher, 1969). In some cases, herbivorous sea urchins move in to feed on algae, creating a pattern against the white coral that resembles the holes of swiss cheese (Tsuda et al. 1970).

Impact


Coral gardens from Micronesia and Polynesia provide valuable marine resources for local communities and environments for native marine species such as marine fish. In coral ecosystems already affected by coral bleaching, excess tourism and natural events such as storms and El Nino, the effects of the invasive crown-of-thorns starfish (Acanthaster planci) on native coral communities contributes to an already dire state of affairs. Acanthaster planci significantly threatens the viability of these fragile coral ecosystems, and damage to coral gardens by the starfish has been quite extensive in some reef systems. Outbreaks in the Pacific appear to be more massive and widespread than those elsewhere. This may reflect different patterns of outbreak between Pacific and Indian Ocean populations, which have recently been shown to form separate clades of an A. planci species complex. (Vogler et al. 2008;and see 'Description' section).


Source: cabi.org
Description

The eggs are pale orange and around 1 mm long and 0.4 mm wide. There are three larval instars. The larvae are off-white with three pairs of legs, a black head and a black dorsal plate on the apical segment. The first and second instars, but not the third are speckled with black tubercles (Ebbe-Nyman, 1952). The approximate sizes of each instar are as follows;
First instars are 1 mm long by 0.3 mm wide,
Second instars are 3-4 mm long by 0.5 mm wide,
Third instars are 5-8 mm long by 0.6 mm wide.
Pupae are off-white, approximately the same dimensions as the adults. The adults are around 3-5 mm long, black, usually with a blue-green metallic sheen but variations in size and coloration occur. The elytra are striated. The head is visible dorsally. The antennae are 10-segmented. They have enlarged metafemora hind legs incorporating a metafemoral springer apodeme, enabling them to jump powerfully. The sexes can be distinguished by the shape of the tarsi.

Recognition

No commercial monitoring traps are currently available for this insect. Although heavy adult infestations in the autumn can destroy crops at the seedling stage farmers are not usually advised to control adult populations (Bonnemaison and Jourdheuil, 1954;Alford et al., 1991). Because of the high winter mortality of the adults and the increased size of the rape plants, adult feeding is not important in the spring (Bonnemaison and Jourdheuil, 1954). To determine larval infestation levels in oilseed rape, a sample of rape leaf stems from across the field should be dissected and larval numbers noted. A less time consuming threshold assessment method, based on petiole scarring, has been suggested (Cooper and Lane, 1991).

Symptons

The adults chew holes in the leaves. The larvae usually mine the lower petioles, moving from ageing to healthy tissue, but will move to the stem and destroy the growing point if larval numbers are large or if the rosette is poorly developed (Ebbe-Nyman, 1952;Bonnemaison and Jourdheuil, 1954;Williams and Carden, 1961). Severe larval attack can distort the plant and cause the epidermis to peel, leading to the death of the plant (Williams and Carden, 1961). As well as causing direct damage, attack by P. chrysocephala is associated with fungal (Leptosphaeria maculans and Phoma lingam) and bacterial (Erwinia) infection, (Bonnemaison and Jourdheuil, 1954;Williams and Carden, 1961;Newman, 1984;Nilsson, 1990). The beetle may transmit turnip crinkle virus (Bonnemaison, 1965). Plants infested with the cabbage stem flea beetle are also more susceptible to frost damage (Winfield, 1992).

Hosts

The host-plant range of P. chrysocephala has not been thoroughly studied, most studies on crucifer-feeding Chrysomelidae concentrating on the genera Phyllotreta and Phaedon. Adults and/or larvae of P. chrysocephala have been recorded from 18 different crop and weed species of the family Brassicaceae but from only three plant species outside this family, namely Thalictrum majus, (Ranunculaceae), Linum usitatissum (Linaceae) and Glycine max (Papilionaceae) (Newton, 1929;Bonnemaison and Jourdheuil, 1954).
However, in laboratory experiments, feeding was almost entirely restricted to the Brassicaceae (Bartlet and Williams, 1991), including Brassica napus, B. oleracea, B. rapa, B. nigra, Sinapis alba, Sinapis arvensis, Eruca vesicaria, Nasturtium officinale, Raphanus sativus, Isatis tinctoria, Alliaria petiolata and Matthiola incana. The only plants outside the Brassicaceae on which feeding was observed were Reseda alba (Resedaceae) and Tropaeolum majus (Tropaeolaceae). These plants contain glucosinolates, secondary chemicals that characterise the Brassicaceae and, in subsequent experiments, Bartlet et al. (1994) showed that glucosinolates are important feeding cues for this species.


Source: cabi.org
Description

For a general description of the genus, see the datasheet on Anastrepha.

Recognition

No male lures have yet been identified for Anastrepha spp. However, they are captured by traps emitting ammonia and it is likely that traps already set for Rhagoletis cerasi in the cherry-growing areas of the EPPO region may attract Anastrepha spp. if they should ever occur in those areas. McPhail traps are usually used for the capture of Anastrepha spp. (Drew, 1982) and possible baits are ammonium acetate (Hedstrom and Jimenez, 1988), casein hydrolysate (Sharp, 1987) and torula yeast (Hedstrom and Jiron, 1985). The number of traps required per unit area is high;in a release and recapture test, Calkins et al. (1984) placed 18 traps per 0.4 ha and only recovered about 13% of the released flies.
Some studies have shown that egg morphology can be used to separate closely related species found in host fruits (Murillo and Jiron, 1994). The larvae of some species may also be differentiated using cuticular hydrocarbons (Sutton and Carlson, 1993). Neither method has yet been generalized for application outside of very specific circumstances.

Symptons

Attacked fruit can show signs of oviposition punctures, but these, or any other symptoms of damage, are often difficult to detect in the early stages of infestation. Much damage may occur inside the fruit before external symptoms are seen, often as networks of tunnels accompanied by rotting. Very sweet fruits may produce a sugary exudate.

Impact

A. obliqua is the most important fruit fly pest of mango (Mangifera indica) in the Neotropics and attacks a broad range of other fruits. It is widespread in Mexico, Central and South America and the West Indies. It is invasive in the Lesser Antilles and was temporarily established in Key West, Florida, USA. It should be considered a serious threat to other tropical parts of the world, particularly mango-producing regions. It is considered an A1 quarantine pest by EPPO.

Hosts

The main native hosts are Spondias spp. (Anacardiaceae), but these are only of local interest. Mangoes [ Mangifera indica ], also Anacardiaceae, are the economically important host, on which the species has extended its range (Hernandez-Ortiz, 1992). Citrus spp. and guavas [ Psidium guajava ] are only occasional hosts. Like other Anastrepha spp., A. obliqua has been recorded incidentally on a wider range of fruits, both tropical and temperate, but these records are incidental occurrences, of no economic significance.
In common with other polyphagous and difficult to identify species, many host records cannot be substantiated and only records confirmed by Norrbom and Kim (1988) or subsequent reliable sources have been accepted here. Post 1988 records include Eugenia stipitata (Couturier et al., 1996).


Source: cabi.org
Damage Aromia bungii
Title: Aromia bungii
Description


Eggs

Recognition


Traps baited with different mixtures have been proposed for detecting adults in the field during the summer months (Gong et al., 2013). Baited traps can also be installed around a site where wood ready for shipment is stored, and for early detection at official points of entry and potentially newly-invaded areas, such as stone fruit orchards. Synthetic pheromone blends of cerambycid beetles have been used to develop trap lures that simultaneously attract multiple species with interesting results in the USA (Wong et al., 2012). In another investigation, A. bungii was not listed among 71 cerambycid species collected in a tropical montane rainforest in southern China by means of traps baited with 10 known cerambycid pheromones (Wickham et al., 2014). Different blends could be tested on A. bungii to verify whether this option for pest surveillance could be considered in the future.
Detailed morphological description of the adult stage is given by several authors for easy identification of A. bungii from cogeneric species Aromia moschata ssp. ambrosiaca and A. orientalis (Plavilstshikov, 1934;Gressitt, 1951;Podany, 1971;Lompe, 2013).
Trees should be inspected, especially trunks and branches, for signs of larval tunnels. Frass extruding from holes in the trees is a sign of infestation (Liu et al., 1999;Garonna, 2012;Garonna et al., 2013;Nugnes et al., 2014a).

Symptons


Damage caused by young larvae of A. bungii can be identified by the presence of small galleries under the bark. Intermediate larval tunnels can be seen in both the sap wood and heart wood of the trunk and larger branches of healthy and unhealthy trees (Gressitt, 1942;Garonna et al., 2013). Considerable amounts of frass (small, cylindrical pellets of sawdust) are ejected through holes bored in the bark. High amounts of frass amassing at the base of an attacked tree may give a good indication of larval infestation. Moreover, the presence of adult emergence holes is sign of old establishment. Exit holes are elliptical in shape (6-10 x 10-16 mm). Several generations can develop within an individual tree, leading to its death. Localized symptoms on basal parts of the tree may be confused with attacks caused by other xylophagous pests. In Europe on Prunus spp. there are typical infestations caused by indigenous pests, like Capnodis tenebrionis, Cerambyx scopolii and Cossus cossus.

Impact

A. bungii is native across the south-eastern Palaearctic and Oriental regions. It is recorded from China, Korea, Taiwan and Vietnam. A. bungii is an oligophagous species;its host range is largely limited to Prunus spp. Other host plants belonging to different families are reported in the literature, for example, from Ebenaceae (Shandong Academy of Environmental Science, 2009) and Salicaceae (Lei and Zhou, 1998), but sometimes with doubtful supporting evidence. In 2008 three adults of A. bungii were intercepted among wooden pallets in a warehouse in Bristol, UK, and during the same year the pest was intercepted in a manufacturing plant at Seattle, USA. In 2011, A. bungii was recorded for the first time from a host tree in Germany (Bavaria). In 2012, it was also reported in Italy (Campania) and in 2013 a new outbreak was found in Lombardia. In 2013 it was again recorded outside its native area, in Japan. Wood packaging material and nursery plants are potential pathways of accidental introduction.

Hosts


In China, A. bungii has mainly been recorded on Prunus spp. The major hosts are fruit tree species, such as apricot, cherry, peach and plum. There are records on other host plant species associated with A. bungii which require confirmation, for example, Diospyros, Juglans (Hua, 2002;Shandong Academy of Environmental Science, 2009), Populus, Quercus and Salix (Lei and Zhou, 1998).


Source: cabi.org
Title: Aromia bungii
Description

Adults

Symptons

The main damage is caused by the larvae, which feed inside the fruit and tunnel through it to exit for pupation. The larval feeding often causes premature fruit drop from the plant and usually rotting of the damaged tissues.

Impact

A. grandis is a pest of various cultivated species of Cucurbitaceae, especially pumpkin (Cucurbita spp.), squash (Cucurbita spp.) and melon [ Cucumis melo ]. It occurs in the Andean countries, Paraguay, southern Brazil, and northern Argentina. It has been intercepted at ports in the USA, indicating its potential for spread via infested fruits.


Source: cabi.org
Description

Light brown apple moth adults are highly sexually dimorphic and variable in wing pattern and colour, although a lighter, diamond-shaped area extending from behind the head to approximately one-third of the body length is typically visible at rest. Male forewing length ranges from 6-10 mm, compared with 7-13 mm in females (Thomas, 1975a). Males tend to have a higher contrast in colouration than females, although the level of contrast varies.

Recognition

Pheromone traps have been widely used for detection and monitoring of populations of this species, since the identification of the sex pheromone (Bellas et al., 1983). A range of applications were reported by Suckling (1993), including insecticide resistance monitoring, insecticide spray reduction, and sample collection for population studies. Pheromone traps were proposed for use in the biosecurity detection of E. postvittana in the USA, in combination with codling moth lures, because there is no cross-talk between these species (Schwalbe and Maestro, 1988). This was apparently not adopted. Bradley et al. (1998) reported the use of traps with a spray threshold for insect growth regulator timing. Shoot tip assessment has also been used on apples [ Malus domestica ]and other crops. Suckling et al. (1998) used time searches for alternative host plants to study the host range. Egg sampling and pheromone trapping is conducted in Australian vineyards (Somers and Quirk, 2005). Trapping of females using fermenting port wine has also been used (Suckling et al., 1994).

Symptons


Larval nests are typically seen as leaves webbed together, or attached to fruit. Fruit surface feeding is common within larval nest sites. On apples [ Malus domestica ], older skin damage has a cork-like appearance, and may be small (5 mm) or larger areas, depending on larval instar and feeding duration. Feeding sites on other fruits are similar.
Vectoring of Botrytis cinerea by larvae has been shown in grapes [ Vitis vinifera ], with up to 13% of berry damage (by weight) caused as a result (Bailey, 1997).

Impact

E. postvittana is a small, bell-shaped moth, whose caterpillars feed on a very wide range of plants. The eggs, larvae and pupae can be associated with plant material and readily transported. The pest status of this insect in horticultural crops is very significant. It is native to Australia and was distributed to New Zealand, Hawaii, New Caledonia and the UK with apples [ Malus domestica ] or other plant material in the late 1800s. It has since spread throughout lowland New Zealand, and in recent years has spread through southern parts of the UK, and Ireland. In Hawaii, it appears to be confined to altitudes above 1100 m, and can largely be considered a pest of temperate regions.

Hosts

E. postvittana has a very wide host range, with 73 listed from Australia (Danthanarayana, 1975;Geier and Briese, 1981), and over 250 from New Zealand (Thomas, 1989;Dugdale and Crosby, 1995). Danthanarayana et al. (1995) have suggested that the better performance of E. postvittana on herbaceous rather than woody plants suggests that it primarily evolved as a feeder on the former. Mo et al. (2006) reported development of this species on Citrus spp.
In Australia, capeweed [ Phyla nodiflora or Arctotheca calendula ], curly dock [ Rumex crispus ] and plantain [ Plantago major ] are important hosts. In New Zealand, important perennial weed hosts are gorse (Ulex europeus) and broom (Cytisus scoparius), and in several regions it has been commonly recorded on annual weeds (Rumex obtusfolius and Plantago spp.), shelter and amenity trees (Salix spp. and Populus spp.) (Suckling et al., 1998). It has readily colonised the native Acacia koa (koa) in Hawaii, USA, along with gorse and other species, and there are also new host records from California, USA. The ecological host range in the existing geographic range has yet to be fully compiled, but it is clearly highly polyphagous.
Detoxification enzyme profile and expression of insecticide resistance is affected by larval host plant (Robertson et al., 1990), as is developmental rate (Danthanarayana, 1975;Tomkins et al., 1989). The larval and adult host plant preferences appear to be independent of each other (Foster and Howard, 1999). The molecular biology of the larval midgut, which can affect host range, has also been examined (e.g. Simpson et al., 2007).
A 1970s survey in New Zealand, conducted by DSIR Entomology Division Horticulture Group, in conjunction with horticultural advisors, returned the following results (Wearing, 2000):
- Exotic host plants: 88 (very common);78 (common);166 (occasional);332 (grand total).
- New Zealand native or endemic host plants: 3 (very common);16 (occasional);19 (grand total).
Larval development was not confirmed on all of the ‘occasional’ hosts.
The host plants recorded in the New Zealand survey were summarised by family (Wearing, 1999) and are included in the host list of this datasheet.


Source: cabi.org
Description

Egg

Symptons


On apple, C. nenuphar can cause two types of damage. In spring, females oviposit in young fruit, marking them with characteristic half-moon shaped scars;and in spring and summer, the adults puncture the fruit causing round (2-3 mm diameter), feeding scars.
The appearance of plum curculio damage is highly variable and, of all fruit damage rated by IPM specialists, damage caused by plum curculio had the lowest average agreement level (71.8%) (Vincent and Hanley, 1997). Internal damage to the fruit is caused by larval feeding and exit holes. Most infested fruits drop prematurely in June, though cherries rot on the trees. Adult feeding may also cause marginal damage to leaves and blossoms.

Impact


The plum curculio, C. nenuphar, is native to North America and restricted to east of the Rocky Mountains. Although it feeds on several wild host plants and several species of cultivated pome and stone fruit, C. nenuphar has not extended its geographical range over the years. Given its life-cycle (larvae complete their development and diapause in the soil), it is not likely to be a global invasive species. It can be considered as a local invader, as it will invade any new orchard plant (apple: Malus;plum: Prunus;peach: Prunus) and thereby become a serious pest of these agricultural habitats.

Hosts


Peaches, apricots and nectarines are the preferred hosts of C. nenuphar but apples are also widely affected. Apples are less damaged in areas adjacent to peach orchards than in areas where peaches are little grown. Pears are often scarred and deformed by the feeding and egg punctures of C. nenuphar but the larvae fail to develop in them (Armstrong, 1958). There are varietal differences in the susceptibility of apples, with eggs being destroyed and larval establishment being prevented by fruit growth in some varieties (Paradis, 1957). The larvae have also been found developing inside leaf curl galls and pockets in plum fruits, caused by the fungus Taphrina communis. The black excrescences of Dibotryon morbosum [ Apiosporina morbosa ] also provide satisfactory food for the larvae (EPPO, 1979). For further information on the hosts of C. nenuphar, see Maier (1990) and Yonce et al. (1995).
With mark and release experiments, Leskey and Wright (2007) established that the order of preference of the host range for C. nenuphar as (in decreasing order of preference): Japanese plum (Prunus salicina), European plum (Prunus domestica), peach (Prunus persica), sweet cherry (Prunus avium), tart cherry (Prunus cerasus), apricot (Prunus armeniaca), apple (Malus domestica) and pear (Pyrus communis).


Source: cabi.org
Description


The egg when first laid is translucent-white, later becoming yellow, slightly convex, round or slightly oval, measuring about 0.7 mm across. The full-grown larva has a length of approximately 12 mm, and is pink to almost red. The head, the prothoracic notum and the anal plate are brown. A black anal fork (anal comb), above the anal opening, is present.
The cocoon is a protective covering for the full-grown larva and pupa. It is made of silken threads and particles of the objects on which it rests. The pupa is reddish-brown. The adult has a wing span of 10-16 mm, and is dark-grey. When at rest, the wings are held in a roof-like position over the body, and the antennae are bent backwards over the wings. For exact identification, investigation of the genitalia is necessary.
Detailed morphology can be found in Balachowsky (1966).

Recognition


The first signs of G. molesta infestation at the beginning of the growing season usually include clearly visible wilting, drying and brown lateral shoot tips (Il’ichev et al., 2003).

Symptons

G. molesta causes damage of varying importance on peaches, nectarines and apricots. The larvae of the first generation are mostly found in buds and shoots of peaches, but occasionally also on shoots of apricots, plums, almonds, cherries, apples, pears and quinces. In young trees when terminal twigs are attacked, several lateral shoots will appear below them and grow rapidly. Under severe and continued attack, the tree may become somewhat bushy. Severe attacks on the rapidly growing shoots of recently budded peaches result in crooked stems.
In harvested peaches there are two distinct types of injury. One is caused by larvae that have abandoned the twigs, feeding on, or entering into, the side of the fruit early in the season when the fruit is small. It is frequently called 'old injury'. The second type of damage is caused by entrance at the stem, called 'new injury', and occurs when the fruit is almost fully grown. This injury is caused by newly hatched larvae that go directly to the fruit. The surface indications of the presence of maggots in the fruit are frequently obscure and occasionally lacking, and only a small part of such injured fruit can be detected during grading. The loss sustained by growers from this type of injury is in reduced prices for their fruit (USDA, 1958). In France, this pattern of injury is characteristically seen on nectarines. On downy-skinned peaches, the reverse may be seen (early attacks at the stalk, later attacks at the side of the fruit). G. molesta damage also favours brown-rot infection (Monilinia spp.). Fruits of other species are also occasionally attacked in the vicinity of peach orchards.

Monitoring


Sex pheromone-based monitoring is the most effective survey method for detecting pest insects. It can be used for early detection and warning of pest invasion, taxonomic and biodiversity investigations, population density and dispersion trends estimation, forecasting and threshold determination, mapping of pest infested areas and risk assessment, recommendation of treatments and timing of application, measuring of treatment efficacy and impact on pest density (Sexton and Il’ichev, 2000).
Timing of chemical treatments can be determined by monitoring with sex pheromone traps and accumulation of degree-days (Rice et al., 1996). Different trap designs and sex pheromone lures were compared in field trials which suggested that sex pheromone traps could be used for monitoring seasonal abundance and determining biofix dates (male catches) for phenology models (Zalom, 1994).
Fermenting brown sugar, molasses, fruit juices and port wine have been used as bait traps to attract G. molesta males and females in fruit orchards, but were not species specific and also attracted many beneficial insects and pollinators (Yetter and Steiner, 1931). The addition of terpinyl acetate to fermenting brown sugar solution traps increased the attractiveness of bait traps to G. molesta males and, most importantly, mated females.
A comparison of sex pheromone and bait trap catches over a number of seasons in Australia demonstrated that they both recorded similar infestation figures and peak moth numbers (Rothschild et al., 1984). Sex pheromone traps designed to attract males in conventional orchards are not reliable under mating disruption. However, terpinyl acetate-fermenting brown sugar solution traps effectively attract G. molesta males and females in orchards under mating disruption treatment (Il’ichev et al., 1999;Il’ichev et al., 2002).
Recently, attempts had been made to combine both traps in one and use it for monitoring of G. molesta in disrupted orchards in Argentina and conventional orchards in Chile (Cichon et al., 2012). New host-plant attractants have recently been tested to improve pest monitoring, particularly for mated females of G. molesta in orchards treated with mating disruption (Il’ichev et al., 2009;Lu et al., 2012).


Source: cabi.org
Description

Leafhoppers of the subfamily Idiocerinae are predominantly found on trees and shrubs. They are characterized by a broad rounded head, extending little between the eyes, and a general 'wedge' shape. According to Viraktamath (1989), 14 idiocerine species, in three genera (Amritodus, Busoniomimus and Idioscopus), breed on mango trees and of these only six are of economic importance. Unfortunately, there is no comprehensive taxonomic treatment available to separate all the mango-associated species.
I. clypealis has the head, pronotum and scutellum yellowish, with two black spots on the anterior margin of the vertex in the female, but these spots are absent in the male. The frons is immaculate;there are two black spots on the fronto-clypeus mesad and basad of the ocelli;the clypellus is completely black. The scutellum is yellowish with a a triangular black spot near each basal angle. The forewings are pale ochraceous. Male genitalia are with an aedeagus with two pairs of long appendages. Males are between 3.7 and 4.2 mm in length;females are 3.8-4.2 mm.

Recognition

Detailed examination of the flower panicles is needed to determine the population size for damage assessment and control studies. Verghese et al. (1985) developed a sequential sampling plan for classifying infestation of I. clypealis into light, moderate and severe on the basis of sample counts. Negative binomial distributions for nymphs and adults were fitted. Operating characteristic values, giving the probability of reaching a correct decision for a range of population means for both adults and nymphs, together with average sample number values, were used to predict the average number of trees to be sampled under different sequential plans. In the case of the closely related I. niveosparsus, studies by Tandon et al. (1989) on the spatial distribution of nymphs on mango trees in Karnataka, India, to determine a sampling plan for the pest showed that nymphs were aggregated on the mango panicles. Their distribution was best explained by Iwao's patchiness regression which showed that mean colony size was fixed and that colonies followed a negative binomial series. The optimum sample size recommended was 59 panicles per tree for damage assessment and control studies, and 98 panicles per tree for ecological studies when greater precision was required. Tandon et al. (1989) found no significant differences in the distribution of nymphs between the north, south, east or west portions of the tree or between the upper and lower canopies, indicating that sampling can be conducted from any point on the tree.

Symptons

Nymphs and adults of Idioscopus species suck phloem sap from the inflorescences and leaves. The affected florets turn brown and dry up, and fruit setting is affected. Other effects of feeding are caused by honeydew on which sooty mould develops, affecting photosynthesis. Some damage may also occur through egg laying into the leaves and flower stems.

Hosts

According to Sohi and Sohi (1990) there are no plants other than mangoes on which I. clypealis will breed;however Viraktamath (1989) and Gnaneswaran et al. (2007) list a range of trees on which adults have been found.

Biological Control
To date there have been few studies where biological control has been attempted against mango leafhoppers, despite the existence of parasitoids and predators (see Natural Enemies). Several fungal pathogens may prove useful for biological control as mentioned by Kumar et al. (1983).<br>Host-Plant Resistance<br>Presumably because of the time needed to grow mango trees large enough to test, there have been relatively few studies devoted to varieties resistant to attack by mango leafhoppers. Murthi and Abrahim (1983) investigated 12 mango varieties for population fluctuations of the hoppers during preflowering and postflowering periods by means of monthly sweeps of trees of uniform age. Progeny production by I. niveosparsus on floral branches was positively associated with the nitrogen content of the branches. Khaire et al. (1987) screened 19 varieties under field conditions for resistance to I. clypealis.

Source: cabi.org
Description

Eggs
The egg of L. botrana is of the so-called flat type, with the long axis horizontal and the micropile at one end. Elliptical, with a mean eccentricity of 0.65, the egg measures about 0.65-0.90 x 0.45-0.75 mm. Freshly laid eggs are pale cream, later becoming light grey and translucent with iridescent glints. The chorion is macroscopically smooth but presents a slight polygonal reticulation in the border and around the micropile. The time elapsed since egg laying may be estimated by observing the eggs: there are five phases of embryonic development - visible embryo, visible eyes, visible mandibles, brown head and black head (Feytaud, 1924). As typically occurs in the subfamily Olethreutinae, eggs are laid singly, and more rarely in small clusters of two or three.
Larvae
There are usually five larval instars. Neonate larvae are about 0.95-1 mm long, with head and prothoracic shield deep brown, nearly black, and body light yellow. Mature larvae reach a length between 10 and 15 mm, with the head and prothoracic shield lighter than neonate larvae and the body colour varying from light green to light brown, depending principally on larval nourishment.
Older larvae are characterized by a typical dark border at the rear edge of the prothoracic shield (Varela et al., 2010) and by the black colour of the second antennal segment. The width of the head capsule is used to distinguish larval instars (Savopoulou-Sultani and Tzanakakis, 1990;Delbach et al., 2010) as well as mandible length (Pavan et al., 2010).

Recognition

Inspection of Grapevine Reproductive Organs
Inspect inflorescences and look for eggs or larvae on flower buds or glomerules. Inspect grapes and look for eggs or larvae, or damaged berries. It is easier to look for larval damage rather than for eggs, because detection of eggs is very tedious and time-consuming, especially under field conditions. Egg detection is always preferable when an insecticidal control has to be programmed.
Corrugated Paper Bands
This technique has sometimes been employed to trap and quantify overwintering pupae. Bands are placed around grapevine trunks or primary branches, and diapausing larvae pupate inside. However, this method is only useful in the last generation, and its reliability is uncertain.
Light Traps
Their lack of specificity makes their use inadvisable when the adult trapping methods described below are available. EGVM flight activity mainly occurs at dusk (Lucchi et al., 2018c);this negatively affects the visibility of the light traps, impacting on their efficiency.
Feeding Traps
These traps were largely used in the past before sexual traps were developed, but may still be useful in particular situations. Trapping females with food-baited traps is a valuable tool to predict the onset of oviposition, an event used to properly time insecticide treatments (Thiéry et al., 2006). An earthen or glass pot is baited with a fermenting liquid (fruit juice, molasses, etc.) and the scents produced attract adults which are then drowned;the population may be estimated by counting. Practical problems include irregularity in trapping because fermentation strongly depends on seasonal temperature, trap maintenance (lure replenishment and foam elimination), and low selectivity. Terracotta pots baited with red wine have been used in Spain to assess the L. botrana mating ratio in mating disrupted vineyards (Bagnoli et al., 2011).
Sexual Traps
Pheromone traps are easier to use compared to feeding traps. They are a sensitive tool to monitor flight of males exclusively, but can be useful to time an ovicidal treatment, and to properly schedule scouting activities in the vineyard. Sexual traps were first suggested by Götz (1939). Chaboussou and Carles (1962) designed traps baited with living L. botrana females, which became increasingly important for monitoring. To obtain a large number of females to bait traps, laboratory rearing methods were improved both on natural substrates (Maison and Pargade, 1967;Roehrich, 1967a;Touzeau and Vonderheyden, 1968), and on synthetic or semi-synthetic media (Moreau, 1965;Guennelon et al., 1970, 1975;Tzanakakis and Savopoulou, 1973). However, sexual trapping became more efficient when the major compound of the L. botrana sex pheromone, (7E, 9Z)-7, 9-dodecadienyl acetate, was described (Roelofs et al., 1973), identified from the female sex gland (Buser et al., 1974), and synthesized (Descoins et al., 1974). In traps, females were promptly replaced by dispensers impregnated with synthetic pheromone, which had essential practical advantages for monitoring. It has now been shown that the L. botrana sex pheromone is a blend of 15 compounds (Arn et al., 1988), but for economic reasons commercial traps incorporate only the major pheromone compound, which has a satisfactory trapping specificity for L. botrana. In Italy, males of few species of non target moths are sometimes captured in L. botrana pheromone traps (Ioriatti et al., 2004).
A major limitation of L. botrana sexual trapping (as often occurs in other insect pests) is the lack of a clear relationship between the number of males trapped and the damage done by their offspring, given the high number of other uncontrolled ecological factors involved. The correlation between these variables has been partially improved by diminishing the pheromone dose in traps (Roehrich et al., 1983, 1986). According to Roehrich and Schmid (1979), only a negative prediction can be made when male catches in traps are sporadic (or nil) can one expect minimal (or even no) damage to be caused by offspring on the crop;but if catches are moderate or high, the damage caused by offspring is unpredictable. Nowadays, the variable performance of the traps on the market, the influence of the trap placement and of the wind direction on the number of catches, make it still difficult to find a strict relationship between catches and infestation, especially when the catches are low.
Scouting
Forecasting models and moth trapping alone do not provide sufficient population density information and need to be supplemented with appropriate field scouting of eggs and young larvae (Shahini et al. 2010).
Insecticides are applied according to action thresholds (AT) on the basis of the resulting infestation assessment (percentage of injured clusters, number of nests per inflorescence, number of eggs and larvae per cluster, number of injured berries per cluster). The action thresholds vary widely depending on the generation, susceptibility of the cultivar to subsequent infection by B. cinerea, and whether berries are being produced for table grape, raisins or wine production.
Modelling
Predictive mathematical models have been developed and tested to forecast the life cycle of L. botrana, integrating both biological and climatic information. Temperature-based models, both linear (degree-days accumulated above a lower threshold) and non-linear (deterministic) have been generated in Switzerland (Schmid, 1978), France (Touzeau, 1981), Slovakia (Gabel and Mocko, 1984b, 1986) and Italy (Caffarelli and Vita, 1988;Baumgartner and Baronio, 1989;Cravedi and Mazzoni, 1990). Major problems affecting the correct inference of tortricid populations using modelling are summarized by Knight and Croft (1991) - it should be noted that prognosis is usually only qualitative. However, modelling can be a useful implement in L. botrana management programmes. Time of the first appearance of adults and hatching of the first eggs can be forecasted by predictive models based on temperature requirements of individual instars and critical conditions for oviposition (Moravie et al., 2006). Unfortunately, forecast models based on Degree Days are empirical and their robustness is strongly dependent on the environment in which they have been validated. Alternative forecasting techniques are currently under development, such as the evaluation of larval age distribution during the previous generation in order to predict the distribution of female emergence (Delbac et al., 2010).

Symptons

The following description refers to grapevine, on which symptoms largely depend on the phenological stage of the reproductive organs.
On inflorescences (first generation), neonate larvae firstly penetrate single flower buds. Symptoms are not evident initially, because larvae remain protected by the top bud. Later, when larval size increases, each larva agglomerates several flower buds with silk threads forming glomerules (nests) visible to the naked eye, and the larvae continue feeding while protected inside. Larvae usually make one to three glomerules during their development which provide protection against adverse conditions, i.e., insulation, rain and natural enemies. Despite the hygienic behaviour of larvae, frass may remain adhering to the nests.
On grapes (summer generations), larvae feed externally and penetrate them, boring into the pulp and remaining protected by the berry peel. Larvae secure the pierced berries to surrounding ones by silk threads to avoid falling. Frass may also be visible. Each larva is capable of damaging between 2 and 10 berries, and up to 20-30 larvae per cluster may occur in heavily attacked vineyards (Thiery et al., 2018). If conditions are suitable for fungal or acid rot development, a large number of berries may be also affected by Botrytis cinerea, Aspergillus carbonarius and Aspergillus niger, which result in severe qualitative and quantitative damage (Delbac and Thiery, 2016). Damage is variety-dependent: generally it is more severe on grapevine varieties with dense grapes, because this increases both larval installation and rot development.
Larval damage on growing points, shoots or leaves is unusual (Lucchi et al., 2011).

Impact

Lobesia botrana should be regarded as a potentially serious pest on a worldwide scale for all the vine-growing areas that are presently unaffected.

Hosts

The host plants listed for L. botrana have been compiled principally from Silvestri (1912), Voukassovitch (1924) and references therein;Ruíz-Castro (1943), Bovey (1966), Galet (1982), Stoeva (1982), Vasil'eva and Sekerskaya (1986), Moleas (1988), Savopoulou-Soultani et al. (1990), Gabel (1992) and Ioriatti et al. (2011).
Despite the wide host range recorded, grapevine is the major host crop in which damage is really important. With regard to wild hosts, Daphne gnidium is the major food plant (Lucchi and Santini, 2011). This species was thought to be the original wild host before the invasion of vineyards by L. botrana in the nineteenth century (Marchal, 1912), although this hypothesis has often been questioned (Bovey, 1966) and is still controversial.
Other hosts not selected naturally by females for egg laying have been tested satisfactorily under both laboratory and field conditions, constituting an adequate larval food;see, for example, Voukassovitch (1924) and references therein, including particularly studies by Dewitz, Wismann, Bannhiol and Lüstner;Bovey (1966) and Stavridis and Savopoulou-Soultani (1998).
However, some crops traditionally assumed in the older literature to be natural hosts of L. botrana, for example, Medicago sativa (lucerne) and Solanum tuberosum (potato), are not in fact naturally selected hosts.


Source: cabi.org
Description

Adult

Impact

There is no evidence of the species being invasive in the regions and countries where it is present. L. cicerina is not on the alert lists of either the International Union for Conservation of Nature (IUCN) or the Invasive Species Specialist Group (ISSG). It is not listed as a regulated species by EPPO in the ‘Action A1/A2 Lists of pests recommended for regulation’ for any of the countries of its occurrence. Its host specialization to only a few plants from the Fabaceae family, the climatic limitations and the great numbers of naturally-occurring parasitoids are some of the factors that prevent the species from becoming an invasive. There are no data about any major introductions of any economic importance.

Hosts

The host plants of L. cicerina are only from the Fabaceae family: Cicer arietinum (chickpea) (Hering, 1957;Spencer, 1973);Hymenocarpus circinnatus (disc trefoil) (Hering, 1957);Melilotus alba (white sweet clover);Melilotus officinalis (yellow sweetclover) (Robbins, 1983);Ononis species, including Ononis arvensis (field restharrow) (BMNH), Ononis hircine (Hering, 1957), Ononis repens (common restharrow) (Hering, 1957), Ononis spinosa (spiny restharrow) (Hering, 1957). There is new record of L. cicerina found as a pest of faba bean (Vicia faba) at Damnhour region in Egypt (El-Serwy, 2003). Spencer (1973) suggested that the primary host plants are likely to be the European plant Ononis spp. because he assumed the centre of origin of L. cicerina to be in Europe. Since chickpea was introduced from India he supposed that a host switch to Cicer was established in Europe. However, recently L. c icerina was confirmed from India (Naresh and Malik, 1989). It is unknown whether or not
Host Plants and Other Plants Affected
Top of page
Plant name|Family|Context
Cicer arietinum (chickpea)|Fabaceae
Hymenocarpus circinnatus|Fabaceae
Melilotus albus (honey clover)|Fabaceae
Melilotus officinalis (yellow sweet clover)|Fabaceae
Ononis|
Ononis repens|Fabaceae
Ononis spinosa|Fabaceae
Vicia faba (faba bean)|Fabaceae
Growth Stages
Top of page
Flowering stage, Fruiting stage, Seedling stage, Vegetative growing stage
Symptoms
Top of page
L. cicerina damages the host plant in two ways;females puncture the plants to feed before ovipositing, but the more serious damage is caused by the larvae, mining the leaves (Lahmar and Zeouienne, 1990). The adult females puncture the upper surface of chickpea leaflets with their ovipositor and feed on the exudates from these, which causes a stipple pattern on the leaflets. In some of the feeding punctures, eggs are inserted just under the epidermis (Weigand, 1990a). The leafminer larvae feed in the leaf mesophyll tissue forming a serpentine mine that later becomes a blotch. The mining activity of the larvae reduces the photosynthetic capacity of the plant and heavy infestation may cause desiccation and premature fall of leaves (Weigand, 1990a). In his original description of this species in 1875, Rondani wrote: “Larva mining the leaves of C. arietinum, frequently causing substantial damage” (Spencer, 1973). Shevtchenko (1937) recorded that mined leaves turned yellow, dry up and many fall prematurely. Lower leaves were attacked first and often only three or four healthy leaves remained on each stem. L. cicerina was found quite common in all the surveyed chickpea fields in Syria (Sithanantham and Reed, 1980), attacking the spring-sown crop more severely than the winter-sown crop and varieties with large leaflets more than those with small leaflets.
List of Symptoms/Signs
Top of page
Sign|Life Stages|Type
Leaves / internal feeding
Leaves / wilting
Leaves / yellowed or dead
Whole plant / early senescence
Biology and Ecology
Top of page
Shevtchenko (1937) made a detailed study of this species in Ukraine. He found that there could be as many as four generations between April and August. Adults emerge from overwintering pupae as temperatures increase at the beginning of Spring. In Slovakia, adults of the hibernating populations emerged in May;the next emergence was in July. Part of this generation completed its life cycle in mid-August and disappeared;the other part remained in diapauses during the winter and completed its life cycle the following Spring (Pastucha, 1996). In Romania, the pest had three to four generations per year and larvae were present throughout the vegetative period (Banita et al., 1992). In a much warmer climate (Morocco), the date of emergence varied between years, but in a single year, most L. cicerina emerged within a week, with little difference between geographical areas (Lahmar and Zeouienne, 1990). In 1983, the time between the first appearance of adults in the fields and the first larval damage was 12 days. In Turkey, Hincal et al. (1996a) reported that the adults of L. cicerina emerged in the second half of April and the first half of May, when average temperature was 9.0-14.3 o C and the ground temperature was 19.2-21.2 o C. The larvae appeared 3 to 20 days after adult emergence when the plants were 5-10 cm high. There were two peaks in the population density of the leafminer: one at the end of May;and the second at the end of June. According to Shevtchenko (1937), the egg stage lasts for 2-3 days, and 42% of the leaves contain a single egg, 45% - two, 9% - three, 2% - four and 2% - five eggs. The larval mine is on the upper or lower surface of the leaf and is linear, shallow, at first greenish, later whitish, winding irregularly and frequently forming a secondary blotch. The life cycle is completed in between 20 and 30 days, the pupal stage lasting generally from 10-12 days in the early generation. Under the conditions of Morocco, the development time of the first generation was only 25 days and was followed by three overlapping generations before the Summer diapauses in July (Lahmar and Zeouienne, 1990). Pupation takes place externally (Spencer, 1976). Shevtchenko (1937) found up to 59 puparia per sq. dm 1.10 -1, the equivalent of 1852 per m 2. Del Canizo (1934) has studied the species in Spain where the main areas of cultivation of Cicer arietinum are Castille, Estramadura and Andalucia and he has confirmed the very large populations frequently present in the early generation when fields of chickpea can be seen with scarcely a single plant unaffected. Environmental Requirements Judging from the distribution, L. cicerina prefers arid, semi-arid and temperate (especially Mediterranean) climate conditions. Higher humidity and higher irrigation levels cause increase of the leafminer population density (Cikman and Civelek, 2006).
Climate
Top of page
Climate|Status|Description|Remark
Aw - Tropical wet and dry savanna climate| Tolerated
60mm precipitation driest month (in winter) and (100 - [total annual precipitation{mm}/25])
B - Dry (arid and semi-arid)| Preferred
860mm precipitation annually
BS - Steppe climate| Preferred
430mm and 860mm annual precipitation
BW - Desert climate| Preferred
430mm annual precipitation
C - Temperate/Mesothermal climate| Preferred
Average temp. of coldest month 0°C and 18°C, mean warmest month 10°C
Cf - Warm temperate climate, wet all year| Preferred
Warm average temp. 10°C, Cold average temp. 0°C, wet all year
Cs - Warm temperate climate with dry summer| Preferred
Warm average temp. 10°C, Cold average temp. 0°C, dry summers
Cw - Warm temperate climate with dry winter| Tolerated
Warm temperate climate with dry winter (Warm average temp. 10°C, Cold average temp. 0°C, dry winters)
D - Continental/Microthermal climate| Tolerated
Continental/Microthermal climate (Average temp. of coldest month 0°C, mean warmest month 10°C)
Ds - Continental climate with dry summer| Tolerated
Continental climate with dry summer (Warm average temp. 10°C, coldest month 0°C, dry summers)
Latitude/Altitude Ranges
Top of page
Latitude North (°N)|Latitude South (°S)|Altitude Lower (m)|Altitude Upper (m)
65
25
0
0
Rainfall
Top of page
Parameter|Lower limit|Upper limit|Description
Mean annual rainfall|430|1500|mm;lower/upper limits
Natural enemies
Top of page
Natural enemy|Type|Life stages|Specificity|References|Biological control in|Biological control on
Dacnusa cicerina| Parasite
Larvae| to species
Tormos et al.,
2008
Diaulinopsis arenaria| Parasite
Larvae| to species
Cickman et al.,
2008
Diglyphus crassinervis| Parasite
Larvae| to species
Cikman et al.,
2008
Diglyphus isaea| Parasite
Larvae| to species
Weigand and Tahhan,
1990
Neochrysocharis ambitiosa| Parasite
Larvae| to species
Cickman et al.,
2008
Neochrysocharis formosa| Parasite
Larvae| to species
Cikman et al.,
2008
Neochrysocharis sericea| Parasite
Larvae| to species
Cickman et al.,
2008
Opius monilicornis| Parasite
Larvae| to species
Cikman et al.,
2008
Opius pygmaeus| Parasite
Larvae| to species
Canizo LDel,
1934
Opius tersus| Parasite
Larvae| to species
Cickman et al.,
2008
Pediobius acantha| Parasite
Larvae/Pupae| to species
Gencer,
2004
Pediobius metallicus| Parasite
Larvae/Pupae| to species
Cikman et al.,
2008
Notes on Natural Enemies
Top of page
Parasites A braconid in Spain was found to parasitize up to 90% of larvae of the first generation of L. cicerina on chickpea, thus effectively reducing populations later in the year (Del Canizo, 1934). The identity of this species is not certain, but it is possibly Opius pygmaeus, which has been confirmed parasitizing L. cicerina in Surrey, England (Fischer, 1972). In more recent studies, again in Spain, Garrido et al. (1992) found the parasitoid Opius monilicornis and Tormos et al. (2008) found Dacnusa cicerina sp. n. Eurytoma sp. is reported as a possible hyperparasitoid of D. cicerina. A comparison is made between the larvae and the adults of several Dacnusa species (Tormos et al., 2008): the adults of D. cicerina are similar to those of Dacnusa rodriguezi. The immature larvae are similar to those of Dacnusa areolaris and Dacnusa dryas, and the mature larvae are very similar to those of D. dryas, from which they differ in having scale-like sensilla on the thorax and abdomen. The venom apparatus is very similar to that of Dacnusa flavicoxa, differing from it in length of the reservoir and the number of gland filaments. The mature larva of Eurytoma illiger has well-differentiated pleural and ventral setae. In Morocco, O. monilicornis was identified (Lahmar and Zeouienne, 1990). Hincal et al. (1996b) reported O. monilicornis in chickpea fields in the region of Izmir, Denizil and Usak, Turkey in 1991-1994. In a study of the parasitoids on Agromyzidae pests in cultivated and non-cultivated areas in Turkey among which L. cicerina was included, a total of six parasitoids from Braconidae and 12 parasitoids from Eulophidae (Hymenoptera) were registered (Cikman and Uygun, 2003). It is not clear which parasitoid parasitizes which host. Later, in the region of Sanhurfa, Turkey, Cikman et al. (2008) found a total of eight parasitoid species on L. cicerina on chickpea: the braconids O. monilicornis and Opius tersus;and the eulophids Diaulinopsis arenaria, Neochrysocharis formosa, Diglyphus crassinervis, Neochrysocharis ambitiosa, Neochrysocharis sericea and Pediobius metallicus. In Ankara province, Gencer (2004) found only one parasitoid attacking larvae and pupae of L. cicerina – Pediobius acantha. Sithanantham and Reed (1980) established that many of the collected larvae and pupae in chickpea fields in Syria were parasitized, but no information was given about the species. Later Weigand (1990a) reported two parasitoids on L. cicerina in Syria: Diglyphus isaea and Opius monilicornis, and El-Bouhssini et al. (2008) reported the parasitoid O. monilicornis. D. isaea has been reported for the first time from Tehran and West Azerbaijan as a parasitoid of L. cicerina (Adldoost, 1995). Several parasitoids are mentioned as present in faba bean fields at Damnhour, Sids and El-Zarka in Egypt on L. cicerina, Liriomyza bryoniae and Liriomyza sativae: D. isaea;Hemiptarsenus zilahisebessi;Chrysonotomyia sp.;Pnigalio sp.;Opius sp.;and Cirrospilus sp. (El-Serwy, 2003). No data is given on which of the parasitoids have emerged from L. cicerina. In Romania, Banita et al. (1992) established the rate of parasitism of L. cicerina in chickpea crops, in Dolj district.
Pathway Causes
Top of page
Cause|Notes|Long Distance|Local|References
Crop production|| Yes
Yes
Spencer,
1973
Plant Trade
Top of page
Plant parts liable to carry the pest in trade/transport|Pest stages|Borne internally|Borne externally|Visibility of pest or symptoms
Growing medium accompanying plants
pupae| Yes
Pest or symptoms usually visible to the naked eye
Leaves
eggs;larvae| Yes
Pest or symptoms usually visible to the naked eye
Seedlings/Micropropagated plants
eggs;larvae| Yes
Pest or symptoms usually visible to the naked eye
Impact Summary
Top of page
Category|Impact
Economic/livelihood
Negative
Economic Impact
Top of page
Cicer arietinum (Kabuli chickpea) grown on about 10 million ha, is the world’s third most important pulse crop (Rheenen, 1991). Kabuli chickpea is important not only as a source of human food, but is also a valuable fodder crop. In the Mediterranean region the chickpea leafminer, mainly L. cicerina, but also Phytomyza lathyri, is the main insect pest occurring in several countries in high densities every year (Weigand, 1990a). In the arid and semi-arid conditions of this region, L. cicerina is listed among the most stressing factors for chickpea growth together with Ascochyta blight (Ascochyta rabiei), and cold (Singh and Jana, 1993). In a report on the cultivation of chickpea in Spain (Govantes and Montanes, 1982), it is mentioned that L. cicerina is the most important pest of the culture. Del Canizo (1934) refers to fields of chickpeas in Spain in which virtually all plants show evidence of leaf-mining attack. The plants were not destroyed, but substantially weakened, with a consequent reduction of yield. Damage to the leaves actively facilitates subsequent fungal attack, referred to locally as “la rabia”, caused by Phyllosticta rabiei. Shevtchenko (1937) refers to the fungal disease in Ukraine as “Ascochyta”. Some economic loss, both in the pea harvest and in foliage for fodder, undoubtedly occurs wherever this crop is cultivated (Del Canizo, 1934). It can be assumed that the mass outbreak that occurred in Ukraine in 1934 was exceptional, but nevertheless L. cicerina must be considered as a major pest, liable at any time when a significant build up of population occurs, to cause serious damage. In a review of the insect pests of faba, lentils, and chickpea in North Africa and West Asia, Cardona (1983) listed L. cicerina and Heliothis spp. as the most important pests of chickpea in the field. In Turkey, in a study of the Agromizid fauna in Sanliurfa province, L. cicerina was found to be seriously damaging cultivated plants together with Liriomyza trifolii (Cikman and Uygun, 2003). In Syria, L. cicerina was found to be quite common in all the surveyed chickpea fields (Sithanantham and Reed, 1980) and Hariri and Tahhan (1983a) pointed out Heliothis armigera, Heliothis viriplaca and L. cicerina as the most economically important pests of chickpea. In another publication, the same authors (Hariri and Tahhan, 1983b) also added Callososbruchus chinensis in addition to these pests. A survey of the damage caused to chickpea in Syria and Jordan carried out in May 1983 (Sithanantham and Cardona, 1984) showed that the damaged caused by L. cicerina was greatest in Northern Syria. The damage caused by L. cicerina was estimated by Weigand (1990a) as serious, reaching up to 30% of seed yield loss. The attacks of L. cicerina, although considered less serious than in spring, are strong enough to cause considerable losses in case of drought at the beginning of the cycle in the south part of Morocco (Kamel, 1990). In India, the major pest problems in chickpea are the pod borer (Helicoverpa armigera and Helicoverpa punctigera), the leafminer L. cicerina, the cutworm Agrotis ipsilon, aphids (Aphis craccivora), semilooper (Autographa nigristigna) and bruchids (Callosobruchus spp.) (Sharma et al., 2007). A study in Romania in 1986-1990 established that about two-thirds of the pest fauna in chickpea crops in the Dolj district comprised of L. cicerina (Banita et al., 1992). The attack was maximal during pod formation and the losses of the leaf mass reached 31-86%. In former Czechoslovakia, L. cicerina was first found in 1988 (Kolesik and Pasticha, 1992) in the region of Borovce and in the next 2 years large infestations were recorded. There are also results showing no significant impact of L. cicerina on the yield. In Slovakia, Pastucha (1996) reported 41% mined leaves from the first generation of the fly and 85% from the second generation. Although quite high, the percentage of the mined leaves did not influence yield, but reduced seed weight. A study on the populations of L. cicerina on eight chickpea cultivars in Turkey in Sanliurfa province showed that there were very minor differences in yield among them, and there was no correlation found between larval density and yield loss (Cikman and Civelek, 2007). A survey in three regions in Turkey (Yozgat, Konya and Eskisehir), showed that L. cicerina and thrips were the most widespread pests of chickpea, but were not economically important (Tamer et al., 1998).
Risk and Impact Factors
Top of page
Invasiveness
Has a broad native range
Abundant in its native range
Fast growing
Impact outcomes
Host damage
Increases vulnerability to invasions
Negatively impacts agriculture
Likelihood of entry/control
Highly likely to be transported internationally accidentally
Uses List
Top of page
General
Laboratory use
Research model
Prevention and Control
Top of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
Control
Cultural control and sanitary measures The effect of planting date on chickpea leafminer infestation along with other items was studied in Aleppo, Syria (El-Bouhssini et al., 2008). Chickpea (Cicer arietinum) planted in Spring had a significantly higher number of damaged leaflets than the winter-sown crop. There were a significantly higher number of damaged leaflets on the local cultivar, as compared with an improved variety (Flip 82-150, ‘Ghab 3’) in both planting dates and both years. For the spring and winter cultivars, there were 1183 and 320 damaged leaflets, respectively, for the local cultivar and 968 and 244 for Ghab 3 in 1998;i.e. a nearly four-fold increase in the number of damaged leaflets between Winter and Spring planting. This study shows that chickpea leafminer could be effectively managed by integrating different pest management options such as winter sowing and use of tolerant cultivars. El-Serwy (2003) is suggesting several agricultural practices i.e. deep ploughing and applying kerosene as control measures against pupae of the leafminer. Higher irrigation levels caused increase of the population density of the leafminer, but on the other hand, yield was higher too (Cikman and Civelek, 2006). Based on the results, highest irrigation levels are recommended in the Sanhurfa province in Turkey. Physical/mechanical control Yellow, moistened traps were more effective in capturing adults than Tullgren funnels or net sweeps (Banita et al., 1992). El-Serwy (2003) tested the effect of spreading the harvested plants on plastic sheets to facilitate collection of the accumulated leafminer pupae. Biological control In most seasons, the populations of L. cicerina are effectively controlled by its parasites. A braconid in Spain was found to parasitize up to 90% of larvae of the first generation of L. cicerina on chickpea, thus effectively reducing populations later in the year (Del Canizo, 1934). In more recent studies, again in Spain, Garrido et al. (1992) found the parasitoid Opius monilicornis and Tormos et al. (2008) found Dacnusa cicerina sp.n. Eurytoma sp. was reported as a possible hyperparasitoid of D. cicerina. In Morocco, O. monilicornis was identified (Lahmar and Zeouienne, 1990). The braconid parasitoids in general were described as the most important natural enemies of L. cicerina, parasitizing 20-35% of the first generation of the leafminer. Hincal et al. (1996b) studied the rate of parasitism of L. cicerina larvae by O. monilicornis in chickpea fields in the region of Izmir, Denizil and Usak, Turkey in 1991-1994. They found that in May and June, parasitism in Izmir was 0-23.91%, 0-29.82% in Denizil and 0-28.33% in Usak. In a study of the parasitoids on Agromyzidae pests in cultivated and non-cultivated areas in Turkey, among which L. cicerina was included, a total of six parasitoids from Braconidae and 12 parasitoids from Eulophidae (Hymenoptera) were registered (Cikman and Uygun, 2003). Later, in the region of Sanhurfa, Turkey, Cikman et al. (2008) found a total of eight parasitoid species only on L. cicerina on chickpea. Leaves with mines were sampled weekly and kept in the laboratory to observe the emerging parasitoids. The braconids O. monilicornis and Opius tersus, and the eulophids Diaulinopsis arenaria and Neochrysocharis formosa occurred both during the Winter and the Summer seasons. Diglyphus crassinervis, Neochrysocharis ambitiosa, Neochrysocharis sericea and Pediobius metallicus occurred only in the Summer growing areas. D. arenaria was the predominant parasitoid with 4-7.7% parasitism rate whereas N. ambitiosa and O. monilicornis were the second and third most predominant species. The results of these trials show that because D. arenaria occurs throughout every season in Turkey, it could potentially be used for control of L. cicerina. Sithanantham and Reed (1980) established that many of the collected larvae and pupae in chickpea fields in Syria were parasitized, but no information is given about the species. Later Weigand (1990a) and Weigand and Tahhan (1990) reported two parasitoids on L. cicerina: Diglyphus isaea and O. monilicornis, and El-Bouhssini et al. (2008) reported the parasitoid O. monilicornis. Several parasitoids are mentioned as present in faba bean fields at Damnhour, Sids and El-Zarka in Egypt on L. cicerina, Liriomyza bryoniae and Liriomyza sativae: D. isaea;Hemiptarsenus zilahisebessi;Chrysonotomyia sp.;Pnigalio sp.;Opius sp.;and Cirrospilus sp. (El-Serwy, 2003). No data is given on which of the parasitoids have emerged from L. cicerina. Synchronization was found between the time of host emergence and the abundance of the larval parasitoid D. isaea in the active season, but not in the diapause season. Asynchrony was observed between the larval-pupal parasitoid Opius sp. and the leaf-mining flies. The population growth rates of larval parasitoids were lower than those of the flies, which retarded the biological control, particularly at the beginning of the season. In Romania, Banita et al. (1992) established the rate of parasitism of L. cicerina in chickpea crops, in Dolj district, and according to the authors it was low;not exceeding 3-4%. Application of insecticides inevitably reduces the population density of the parasitoids and hence, their efficacy. The population of the parasitoid O. monilicornis on L. cicerina on chickpea in Syria was significantly reduced by treatments with deltamethrin compared to treatments with neem oil or the control (El-Bouhssini et al., 2008). In their study, Cikman and Kaplan (2008) established that treatments with azadirachtin influence the rate of parasitism less than treatments with cyromazine. The rate of parasitism in the experimental plots was 35.08-31.64% and 16.98-18.18%, respectively. The insecticidal efficacy of aqueous and methanol extracts from fruits of the Chinaberry tree, Melia azedarach was tested against the chickpea leafminer in Syria (Al-Housari et al., 2003). The results revealed that both extracts significantly reduced the mean percent of the leaflet damage and feeding punctures at all concentrations compared with the control. The highest concentration of methanol extract (2%) gave the highest reduction in percent leaflet damage. No phytotoxicity was observed on treated plants. The insecticidal effect of different seed extract levels (1, 2, 3 and 4 kg seeds/10 litres water) of the same plant (M. azedarach) on the larvae of L. cicerina was investigated at Usak and Denizil-Tavas, Turkey (Hincal et al., 2000). The larvae were counted on 25 damaged leaves in each plot. The seed extract level of 3 and 4 kg seed/10 litres water was effective against the larvae of L. cicerina for 15 days when both adults and larvae were present. Cikman et al. (2008) investigated the effect of Bacillus thuringiensis on L. cicerina in the chickpea growing region of Sanlurfa, Turkey. B. thuringiensis was applied at a concentration of 60 x 106/mg B. thuringiensis spores. It was applied at the recommended rate of 75g/100 litres water. Application dates were chosen when the pest density reached a level of two to three larvae/leaf in 50% of the plants in the field, which is the economic threshold. The leaves were sampled weekly from treated (with cyromazine and B. thuringiensis) and control plots and kept in the laboratory under observation to compare the number of emerging leafminer adults and their parasitoids. Both cyromazine and B. thuringiensis reduce the number of the leafminer compared to the control. There was no difference between cyromazine and B. thuringiensis treated plots for average number of adults and larvae. The percentage of parasitism in the B. thuringiensis -treated plots was higher than in cyromazine-treated plots and was 37.70-35.08% and 15.79-13-33%, respectively. A commercial neem insecticide was compared with cyromazine for its efficacy against L. cicerina (Cikman and Kaplan, 2008). Field trials were carried out from March to June 2006-2007 in chickpea-growing areas of Sanliurfa, Turkey. Azadirachtin was applied at a concentration of 1% (NeemAzl T/S 0.01% A.I.). For comparison, cyromazine 75% (Cyrogard 75 WP) was applied at the recommended rate of 20g/100 litres water. There was no difference between azadirachtin A and cyromazine treated plots for average yield. Chemical control In 1990 in Syria, a recommendation was given for application of Nuvacron or Thiodan at flowering (Weigand, 1990a). However, the use of insecticides may not be either practical or economical for the small farm holders in the region. In a study in 1986-1990, Banita et al. (1992) established that various chemicals applied at commencement of pod formation substantially reduced infestation of L. cicerina and increased yield, especially Trigard (cyromazine), Thiodan (endosulfan) and Fastac (alpha-cypermethrin). El-Bouhssini et al. (2008) tested the efficacy of deltamethrin and neem oil against L. cicerina and their influence on the parasitoids. Both neem oil and deltamethrin significantly reduced leaflet damage in the two cultivars tested. However, deltamethrin significantly reduced the number of adult parasitoids compared with the unsprayed control and neem oil treated for the Spring-sown chickpea. Host Resistance Although the breeding history of C. arietinum is short, considerable progress has been made in cultivar improvement (Rheenen, 1991). Breeding cultivars with resistance to freezing, Fusarium oxysporum f. sp. ciceris, Ascochyta rabiei and Helicoverpa armigera, and for short duration, are examples of successes. Yield stability has increased and yield gains of 1.6% per annum have been achieved. In the West Asia and Mediterranean regions, drought avoidance by Winter sowing has been achieved by incorporating disease resistance and changing the sowing date. This has resulted in a 75% yield increase. A 20% yield increase was recorded in Peninsular India because of the extra-short duration. Desirable traits include resistance to high temperature, salinity, Botrytis cinerea, Sclerotinium rolfsii, L. cicerina and stunt caused by bean leaf roll luteovirus. Attention should also be given to the problems of chilling and lodging in the most productive chickpea-growing areas. The possibility of applying new biotechnological methods for genetic improvement, particularly the use of interspecific crossing, micropropagation, somaclonal variation, and isoenzyme and RFLP mapping, are discussed. The main approach for chickpea integrated control in Syria is screening for resistance to L. cicerina (Weigand, 1990b). In 1991, a catalogue of kabuli chickpea germplasm was published (Singh et al., 1991), presenting data on the evaluation of 6330 Winter-sown accessions of resistance to eight biotic and abiotic stresses (Ascochyta rabiei, Fusarium oxysporum f. sp. ciceris, L. cicerina, Callososbruchus chinensis, Heterodera ciceri, cold, herbicides and iron deficiency). Lists were provided of passport information (donor and origin) and evaluation data (24 descriptors) for each accession. Two hundred accessions of wild Cicer species were evaluated for resistance to L. cicerina in Aleppo, Syria (Singh and Weigand, 1995). Accessions were screened under natural insect infestation in the field in March-June along with a susceptible control line (C. arietinum ICL482). Two accessions of Cicer cuneatum (ILWC40 and ILWC 187) and 10 accessions of Cicer judaicum (all ILWC lines) were rated as 2 on a scale of 1-9, where 1 = free from any damage and 9 = maximum damage. Another 18 lines of C. judaicum, four of Cicer pinnatifidum and one of Cicer reticulatum were rated as 3 (resistant). Three species were incompatible in crossing with chickpea, but C. reticulatum is being used in a breeding programme. Seeds from one leafminer (L. cicerina) resistant line (ILC5901) were exposed to 40, 50 and 60 kR (Omar and Singh, 1995). The M 1 generation was sown at Tel Hadya, Syria during Winter. Germination was reduced at high dosages. Survival to maturity was drastically reduced especially after the 60 kR treatment. The percentage of sterile plants was highest at a dosage of 40 kR g rays. The parental lines and the M 1 generation were grown in 1993. Of the 3292 progenies harvested from the M 1, three were very early, six were early, 295 were medium and the remaining 2994 were late to very late in maturity. The six early plants were harvested individually;seeds from five of the six produced early maturing progeny. None of them segregated for maturity or any other observable character. All of these early mutants produced a higher seed yield than the parental lines and resistance to ascochyta blight or leafminer. Singh et al. (1998) evaluated data on 228 accessions of eight annual wild Cicer species and 20 cultivated chickpea check lines for diversity in response to six of the most serious biotic and abiotic stresses that reduce crop yield and production stability of chickpea, i.e. ascochyta blight (A. rabiei), fusarium wilt (F. oxysporum f. s. ciceris), leafminer L. cicerina, bruchid C. chinensis, cyst nematode H. ciceri and cold. Relative frequencies of score reactions to the above six stresses were recorded from all the annual wild Cicer species and the cultivated taxon. Patterns of distribution and amount of variation of the resistance reactions differed between stresses and species. Cicer bijugum, Cicer pinnatifidum and Cicer echinospermum showed accessions with at least one source of resistance (1 to 4 score reactions) to each stress. Overall, C. bijugum showed the highest frequencies of the highest categories of resistance. Next in performance was C. pinnatifidum followed by C. judaicum, C. reticulatum and C. echinospermum. Furthermore, C. bijugum had the highest number of accessions with multiple resistance to the six stresses: two accessions were resistant to five stresses and 16 to four. According to Shannon-Weaver diversity indices (H’), five species showed discrete mean diversity indices that varied from 0.649 in C. pinnatifidum to 0.526 in C. judaicum, whereas Cicer chorassanicum, Cicer cuneatum and Cicer yamashitae showed the lowest H’ values, which were 0.119, 0.174 and 0.216, respectively. Pair-wise correlation among the six biotic and abiotic stresses showed the possibility of combining these resistances. Interestingly, multiple resistant accessions were predominantly of Turkish origin. The International Center for Agricultural Research in the Dry Areas (ICARDA) screened 6025 germplasm lines of chickpea for resistance to L. cicerina (Singh and Weigand, 1996). ILC3800 and ILC7738 (PI58039 to PI587041, respectively) were consistently rated resistant (3 on a scale of 1 [free from insect damage] to 9 [severe mining on almost all leaflets]) and 30% defo


Source: cabi.org
Description

L. neglectus was only described in 1990 from a population in Budapest, Hungary (Van Loon et al., 1990). It is a member of the sub-family Formicinae. The length of the worker, queen and male are 2.5-3mm (worker), 5.5-6mm (queen), 2.5mm (male);the mandibles are 7-toothed;hairs are lacking on the scape (first segment of antenna) and usually on the legs. Their colour is yellowish-brown with the thorax somewhat paler. The live weight of the worker is 0.65-0.80mg and the queen, 6.8-9.6mg. Espadaler and Bernal (2004) observed that "the female is immediately recognisable within the European Lasius by its comparatively reduced size and proportionately smaller gaster (swollen part of abdomen), as compared with the thorax. The male is the smallest within the European Lasius (s.str.) species".

Impact

Lasius neglectus, known as the invasive garden ant, is a recent arrival in Europe from the Middle East, first recognised in Hungary in 1990. Some populations have attained pest status but at other sites, the ant is still in an arrested state, perhaps in the lag-phase lacking the major characteristics of invaders. Negative effects are reported in buildings, where the ants are a nuisance to residents, a pest in food preparation areas and cause damage to electrical installations, and also where high numbers of ants tend aphids on trees producing quantities of honey dew and the ensuing sooty mould. There is some evidence that native ant species have been displaced.


Source: cabi.org
Damage Dieback
Description

S. vayssierei is the only known hypogeal (below-ground) species in the family Stictococcidae (Tindo et al., 2006). It is a Sternorrhynchan with incomplete metamorphosis. Ngeve (2003a) described the males as rare and the more common adult female as dark-red, circular and flattened. In contrast, Tindo et al. (2006) described the adult females as brown and the first and second instars as purple-red.

Symptons

Young feeder roots of germinating cassava cuttings are attacked by both the nymphs and adults of S. vayssierei. The feeding damage causes premature leaf-fall, wilting, tip dieback and ultimately results in death. Those plants that are not attacked until later develop normally and tuberize, however, they exhibit small mature tuberous roots and become covered in scales, making them unsuitable for sale (Ngeve, 2003a).

Hosts

S. vayssierei feeds on the root system of cassava (Manihot esculenta), affecting tuber formation of the plant (Williams et al., 2010);however, there is evidence to suggest either polyphagy or involvement of more than a single scale species (Tindo et al., 2006). Sixteen plant species belonging to 13 families have been identified as hosts of S. vayssierei in the Congo basin (Tindo et al., 2009;see Host Plants/Crops Affected), but this may reflect the involvement of more than one species, as yet unidentified. It is thought that native Dioscorea species may play an important role in maintaining Stictococcus populations during long fallows and in secondary and primary forests. Cassava, an exotic plant in this area, may contribute to the growth of S. vayssierei in fallows less than 8 years old (Tindo et al., 2009).

Biological Control
According to Ngeve (2003b), biological control agents such as endomycorrhizae should be studied to determine their usefulness in pest control in Cameroon farming conditions.

Source: cabi.org
Damage Scald
Description

Macadamia nutborer is a major pest of lychee and longan fruit, and significant infestations occur in most seasons.

On hatching, larvae bore through the skin and into fruit in search of the seed. When this occurs in green fruit, the fruit will drop, however the larva will most likely still develop to maturity in the fallen fruit, if ground predators don't discover it. Ripening fruit generally does not fall, and the larva often drowns in the juice if the skin is penetrated in the equatorial region where the flesh is thickest.

The rind tissue around the entry hole may appear to be scalded, and such damage is sometimes wrongly attributed to fruit fly, which rarely attacks lychees and longans. Entry on the shoulder or near the peduncle is more likely to ensure survival of the larva enabling it to reach the seed. Mature fruit damaged by macadamia nutborer may weep and stain other fruit in the cluster or those hanging below. One larva can cause perhaps 10% more damage through this secondary staining effect.

Recognition

Description of adult

The moth is reddish-brown and measures 23-25 mm across the extended wings. The male is smaller than the female, which has a large dark triangular blotch two thirds of the way along the hind margin of each forewing.
Immature stages

The scale-like eggs, which are laid singly on the fruit, are oval, approximately 0.8 mm long, and change colour from ivory-white when first laid, to pink then black just prior to hatching. Fully-grown larvae are up to 20 mm long, and pinkish with discrete, dark green spots. Three or four days before pupation they construct tightly woven silken cocoons that are sealed with an unobtrusive flap, providing an exit for the emerging moth. Pupation occurs in damaged fruit, and sometimes in sheltered sites in other parts of the tree. When the moth emerges, the pupal case is left protruding from the exit hole.

Monitoring

Examine five fruit panicles on 20 trees widely spaced throughout the crop, commencing when green fruit are 20 mm long (for lychee and longan). Spray if more than five out of 100 panicles are infested with live, unhatched and unparasitised eggs. Check developing fruit weekly for larval entry holes and/or frass. Infestation levels increase as the fruit mature due to immigration of moths from alternative hosts. Oozing juice from maturing fruit may also indicate a nutborer infestation.

Description

Leafhoppers of the subfamily Idiocerinae are characterized by a broad, rounded head, extending little between the eyes, and a general 'wedge' shape. Unfortunately, there is no comprehensive taxonomic treatment available to separate all the mango-associated species.;I. nitidulus has been illustrated by Maldonado Capriles (1964) and Hongsaprug (1993). The vertex has brownish suffusions on each side of a central line, the posterior margin and laterally before the eyes are yellowish. The face is with two discal brown spots. The ocellus is inside a round, yellow spot, another spot of the same size and colour is adjacent to this spot. The pronotum is dull pale green with irregular, brownish and yellowish spots and markings. The scutellum is pale ochraceous with three basal blackish or dark-brown spots. The forewing is bronzed and subhyaline, veins are brownish, and the costal area is straw coloured. There are white markings on the forewing near the humeral angle, at the claval cells and on the veins.

Symptons

Nymphs and adults of Idioscopus species suck phloem sap from the inflorescences and leaves. The affected florets turn brown and dry up, and fruit setting is affected. Other effects of feeding are caused by the bugs excreta (honeydew) on which sooty mould develops, affecting photosynthesis. Some damage may also occur through egg laying into the leaves and flower stems.

Host plant resistance

Presumably because of the time needed to grow mango trees large enough to test, there have been relatively few studies devoted to varieties resistant to attack by mango leafhoppers. Murthi and Abrahim (1983) investigated 12 mango varieties for population fluctuations of the hoppers during preflowering and postflowering periods by means of monthly sweeps of trees of uniform age. Progeny production by I. nitidulus on floral branches was positively associated with the nitrogen content of the branches.

Biological Control
To date there have been few studies where biological control has been attempted against mango leafhoppers, despite the existence of parasitoids (see Natural Enemies).

Source: cabi.org
Description

A. grandifolium is a perennial herb or shrub that grows up to 3 m tall. Its branches are covered with long and slender hairs. The leaves are simple and alternate and are borne by a 5-20 cm long petiole. Awl-shaped, caducous stipules are found at the base of the petiole. The leaf’s blade is ovate, up to 20 by 15 cm, its base is cordate and its apex acute or subacuminate. Leaves have a toothed margin, 6-7-nerved. Both surfaces of the leaf are covered with stellate hairs. Inflorescences bearing one or two flowers are located in the leaf axils. The peduncles (main stalk of the inflorescence) are shorter than the petioles (4 to 5 cm long and up to 12 cm in mature fruits). Flowers are bisexual and lack the epicalyx. They have five yellow petals, which are united at the base of the staminal colum and enclosed by a 5-lobed calyx, 1 to 1.5 cm long. The staminal column is very short (5-8 mm long) with many stamens. The style branches are yellow, stigmas maroon and the ovary superior. The fruit is subglobose and splits into single-seeded parts when dry. Each fruit contains two to five blackish, kidney-shaped and sparsely pubescent seeds.

Impact


Native to South America, A. grandifolium is widely cultivated as a fibre plant and ornamental in the tropics where it has become naturalized. This garden escape is a relatively common weed of waste areas, disturbed sites, roadsides and drains, but is also an occasional weed of disturbed and undisturbed natural ecosystems (e.g. tall shrublands, grasslands and riparian areas). Given this species’ prolific seed production A. grandifolium has become a problematic weed in some of the regions where it occurs. There is little information available on the impacts of this species. However in Hawaii, along with other invasive species, it is reported as having a detrimental effect on Spermolepis hawaiiensis and Scaevola coriacea, two endangered and threatened species.

Hosts


In spite of the reported damage caused by its congenic species A. theophrasti, there is no indication that A. grandifolium can reduce crop yields or increase costs (CGAPS, 2014)


Source: cabi.org
Description

C. deauratella is a small moth with a wingspan of 11-13 mm (Gustafsson, 2010;UKMoths, 2018a). The adult moths are described as 9.5-15.5 mm by Landry (1991), about 9 mm long by PNWHandbooks (2018), and 10.5-12.5 mm by British Lepidoptera (2018).

Symptons

White eggs are laid on the calyx of the florets and hatch into larvae that chew into unopened florets of T. pratense to feed (Landry, 1991;Yoder and Otani, 2007). As they feed, they bore into adjacent florets, damaging the reproductive structures and available nectary (Landry, 1991;Ellis and Bjørnson, 1996;Yoder and Otani, 2007). The damage they cause can be seen by pulling apart the inflorescences and looking for 2-3 mm diameter holes at the base or calyx of individual florets.

Impact

Coleophora deauratella is a moth species native to Europe, eastern Siberia and the Middle East.

Hosts

Although C. deauratella larvae feed on both Trifolium pratense and T. hybridum in Canada, there have been no reports of damage from T. hybridum seed crop fields (Yoder and Otani, 2007).


Source: cabi.org
Description


IYSV is a tospovirus, similar to the type species of the genus, Tomato spotted wilt virus (TWSV). The virus particles of IYSV are protein-enveloped RNAs and consist of three genomic RNA segments: Large (L), Medium (M) and Small (S). The entire genome codes for six essential proteins via five different open reading frames. The L RNA is negative-sense coding for a polymerase, the M RNA codes for two glycoproteins (GN and GC) and a non-structural protein (NSm), and S RNAs are ambisense and code for the nucleocapsid (N) and the non-structural (NSs) proteins (Pappu et al., 2008). The three RNAs are tightly linked with the N protein to form ribonucleoproteins (RNPs). The RNPs are encased within a lipid envelope (Pappu et al., 2009). Serological divergence exists among tospoviruses, and little cross reaction among antisera is observed (Pozzer et al., 1999). PCR based detection is possible and is used for diagnostics.

Recognition


Where IYSV infection is suspected, samples should be sent to a diagnostic laboratory for ELISA and PCR testing. The distribution of IYSV within an infected plant is uneven and samples should be taken in close proximity to the lesion (Gent et al., 2006;Pappu et al., 2008).
There is evidence to suggest that iris yellow spot (or a disease causing similar symptoms) may also be caused by Tomato spotted wilt virus (TSWV) or co-infection of TSWV and IYSV (Gent et al., 2006). Mullis et al. (2004) showed that a small proportion of onion plants displaying iris yellow spot-like symptoms were infected with both TSWV and IYSV. This is not surprising as thrips can transmit both viruses (and many others). This phenomenon has not been reported elsewhere and co-infection (TWSV and IYSV) on onion remains speculative.

Symptons


Symptoms of IYSV consist of eyespot to diamond-shaped, yellow, light-green or straw-coloured lesions (sometimes necrotic) on the leaves, scape and bulb leaves of onion and other Allium host species. In the early stages of infection, lesions appear as oval, concentric rings. Some green islands can be observed within the necrotic lesions. They usually originate around a thrips feeding point. Infected leaves eventually fall over at the point of infection during the latter part of the growing season. Infection at early stages of crop growth results in yield losses. Infection at later stages of development can still cause significant losses due to reduced quality: severely infected fields will senescence prematurely and entire areas will turn brown before they collapse. Symptom severity is dependent on host cultivar, timing of infection, overall health of the host at the time of infection, and environmental conditions (Gent et al., 2004). Du Toit (2005) reported that out of 46 onion cultivars tested, all but 3 had a significant yield decrease and reduced bulb size. The incidence of symptomatic plants generally increases after bulb formation (Gent et al., 2006). IYSV does not always kill its host(s);however, the virus reduces plant vigour, disturbs photosynthesis and reduces bulb size. IYSV infection weakens the plants making them more susceptible to other diseases and pests. IYSV-infected onions grown for seed have reduced seed yield and quality (Evans and Frank, 2009;Pappu et al., 2009).

Impact


In 1981, de Avila et al. (1981) described a disease characterized by chlorotic and necrotic, eye-like or diamond-shaped lesions on onion scapes (referred to as ‘sapeca’) in southern Brazil. In 1989, Hall et al. (1993) observed a very similar disease in onion in the USA and detected a tospovirus, which was later shown by Moyer et al. (1993) to be Iris yellow spot virus on the basis of molecular and serological data. In 1998, a new tospovirus was isolated and characterized in the Netherlands from infected iris and leek and named Iris yellow spot virus (IYSV) (Cortês et al., 1998). This virus was subsequently found naturally infecting onion in several major onion-producing states of the USA and around the world (for reviews, see Gent et al., 2006 and Pappu et al., 2009). Gera et al. (1998b) reported that IYSV was responsible for a ‘straw bleaching’ disease on onion in Israel. In 1999, a ‘sapeca’ isolate from Brazil was identified as IYSV on the basis of biological, serological and molecular data (Pozzer et al., 1999). In Israel, Kritzman et al. (2000) reported natural IYSV infection of lisianthus grown in the field. IYSV has now been endemic in south-western Idaho and eastern Oregon in onion, leek and chive seed production fields for over 10 years. Losses caused by IYSV can reach 100% in onion crops, for example, in Brazil (Pappu et al., 2009). However, studies in the Netherlands in 2008 showed that latent infections of IYSV were common in onion crops but did not cause economic damage (NPPO of the Netherlands, 2008).

Hosts


IYSV has a relatively restricted host range. Edible A llium crops including onion (bulb and seed crops), garlic, chive, shallots, leeks and some cut flower/potted ornamental species including Alstroemeria, chrysanthemum, iris and lisianthus are the most economically important crops affected by IYSV. Wild Allium species and ornamental alliums are also potentially at risk. A range of weed species (Datura stramonium, Nicotiana spp. and Amaranthus retroflexus) can also act as reservoirs.
Six species have been mechanically inoculated in experimental host range trials (Chenopodium amaranticolor, C. quinoa, Datura stramonium, Nicotiana benthamiana, N. rustica and Gomphrena globosa). There is no evidence that these species are infected in the wild. Ben Moussa et al. (2005) reported infection of another three members of the Solanaceae (capsicums, potatoes and tomatoes) but it is unclear if these are natural hosts or were artificially inoculated.


Source: cabi.org
Description

C. scoparius is an unarmed leguminous shrub, having several erect or ascendant stems which can later collapse to become prostrate where crushed by snow (Hosking et al.,1998). Plants grow to 4 m high, and often form dense thickets in cooler areas. Branches are green, five-angled and mostly glabrous. Leaves are usually three-foliate, petiolate to subsessile, but one-foliate and sessile on young growth. Leaflets are narrow-elliptic to obovate, 5-20 mm long and 1.5-8 mm wide, with scattered hairs on the upper surface and numerous short hairs on the lower surface. Flowers are pedicellate, solitary or in pairs, and borne in the axils on 1-year-old stems. The calyx is glabrous, ca 6 mm long, two-lipped, upper lip with two teeth, lower lip with three teeth, all teeth usually much shorter than the lips. The corolla is golden yellow, 15-25 mm long. Fully developed pods are 2.5-7 cm long and 8-13 mm wide, oblong, dehiscent, strongly compressed, with brown or white hairs on the margin, otherwise glabrous, initially green then black at maturity. Plants are deciduous in winter in colder areas and in summer in areas with summer drought. The plant is most easily distinguished from other closely related species by its five-sided green stems, its yellow, pea-like flowers, and pea-like pods mainly 2.5-7 cm long with hairy margins (see Pictures). In the field, broom plants are conspicuous because of their dark green colour (compared to e.g. the grey-green colour of the more robust C. striatus) and especially their abundant large flowers at the peak of flowering.

Impact

C. scoparius is a perennial shrub that has been widely commercialized as an ornamental in temperate and subtropical regions of the world. It is a prolific seeder that escaped from cultivation and has become an invasive species and a serious weed in temperate areas of the United States, Canada, Hawaii, Chile and Argentina, the eastern halves of both islands of New Zealand, Australia (including Tasmania), India, Iran, Japan and South Africa (Holm et al., 1979;Parsons and Cuthbertson, 1992;Hosking et al., 1998;Peterson and Prasad, 1998;Isaacson, 2000). C. scoparius is an aggressive fast-growing invader with the capability to grow forming dense impenetrable monospecific stands that degrade native grasslands, forests, rangelands, and agricultural lands;prevent the regeneration of natural forests and prairies;and create fire hazards (Syrett et al., 1999;USDA-NRCS, 2016). Because of its association with nitrogen fixing bacteria, it is very competitive in areas with poor soils and can alter the nutrient cycling of invaded areas (Peterson and Prasad, 1998).
C. scoparius is also very common and widespread within its native range and reaches densities where it is considered a weed (Maury, 1963;Engel, 1964). Consequently, in many European countries (within its native range) it has been included in national lists of invasive species (DAISIE, 2016). However, treating this species as invasive in areas within its native distribution range is controversial as it has been present in the European flora for centuries and in many countries where it is now listed as invasive it was previously listed as native (Rosenmeier et al., 2013;DAISIE, 2016).

Hosts

C. scoparius is a significant weed of forestry, particularly in pine and eucalypt plantations around the world. It either smothers planted saplings or reduces their growth (Peterson and Prasad, 1998;Barnes and Holz, 2000). In some areas, C. scoparius can be beneficial in these situations as a nurse crop protecting samplings from frost damage and other types of exposure (Peterson and Prasad, 1998), but it can also be associated with higher levels of plantation diseases (Peterson and Prasad, 1998). Once the plantation species grow above plants of C. scoparius, the impact on tree growth is minimal. In native woodland situations broom can prevent natural regeneration by shading (Hosking et al., 1998) and allelopathy (Nemoto et al., 1993).


Source: cabi.org
From Wikipedia:

Damage is any change in a thing, often a physical object, that degrades it away from its initial state. It can broadly be defined as "changes introduced into a system that adversely affect its current or future performance". Damage "does not necessarily imply total loss of system functionality, but rather that the system is no longer operating in its optimal manner". Damage to physical objects is "the progressive physical process by which they break", and includes mechanical stress that weakens a structure, even if this is not visible.