Activity

Q&A

Activity
Description

The adult of M. semipunctatum is a wingless, black beetle with a convex, often elongate, dull to shining, glabrous body. Females are 15Ð30 mm long and males 15Ð26 mm long. M. semipunctatum has small pronotal spines, large punctures on the disk of the pronotum, and a lack of pubescent patches on the coxae. There are some geographical variations in morphology, in northern populations, punctuation of the pronotum is denser and the integument is often duller than in southern populations (Linsley and Chemsak, 1984).

Symptons

Adults feed on the succulent portions of cacti and the larvae feed near the root collar and within the stems. Feeding activity by boring larvae of M. semipunctatum on Opuntia can be recognized above ground by the tar-like excrement of the larvae and the fluids expelled by the plant from the wounds they create (Evans and Hogue, 2006). Adult feeding by Moneilema spp. can often result in severance of the joints in Opuntia, which fall to the ground and frequently take root, aiding dissemination of the plants. Heavy infestations of the beetles can kill the plants (Woodruff, 1966). Although M. semipunctatum is not generally lethal for Opuntia plants, which can propagate vegetatively, the effect of the beetle on Sclerocactus varies with the host species (Woodruff, 2010). Infestation by M. semipunctatum has been reported as a significant but localized source of mortality of all Sclerocactus species on the Colorado Plateau, particularly of larger, mature, reproducing individuals (Utah Ecological Services Field Office, 2010).


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

C. cardunculus is an erect perennial herb that can grow between 60 and 150 cm, but has been known to grow as tall as 2 m with a spread of 2 m (Weeds of Australia, 2016;Elzebroek and Wind, 2008). It has a large taproot that regenerates each year (Kelly and Pepper, 1996). The root can grow to the depth of 2 m (Parsons and Cuthbertson 2001). The stems are thick and rigid, which often branch in the upper parts, they are longitudinally ribbed and covered in a cotton down. The above-ground portion of the plant dies down each year, but off-shoots rise from the rootstock next growing season (Elzebroek and Wind, 2008).

Impact

C. cardunculus is an erect perennial herb, commonly known as cardoon or artichoke thistle. Native to southern Europe and North Africa, it has been widely introduced and is recognised as invasive in parts of Australia, the USA, Chile and Argentina. It can form dense monocultures, displacing native vegetation and degrading native plant communities. In California, it is categorized as a Most Invasive Wildland Pest Plant, category A-1, on the Californian Exotic Pest Plants of Greatest Ecological Concern. It can aggressively invade and disrupt natural habitats and has been described as a robust invasive plant that exhibits characteristics of the world’s worst weeds.

Hosts

C. cardunculus is known to be a significant agricultural pest, in particular pastoral activity (Weeds of Australia, 2016). Once established C. cardunculus can become the dominant vegetation in an area by monopolising light, moisture and nutrients from the soil. In Australia it has known to adversely affect pastures, and lucerne, by crop contamination. The prickly nature of the herb deters grazing sheep and cattle (Parsons and Cuthbertson, 2001). A thick infestation can also limit the movement of livestock (Thomsen et al., 1986).

Biological Control
<br>Biological control is not feasible as C. cardunculus has closely related cultivated species, Cynara scolymus and Cynara altilis. It is unlikely that any biological control would therefore be restricted to C. cardunculus (Thomsen et al., 1986).<br>However in the USA, the accidentally introduced artichoke fly attacks the flower head of C. cardunculus. It is not an approved biocontrol agent and does not significantly affect commercial C. scolymus crops. The fly’s affect on native thistles is still being studied, and the impact on C. cardunculus populations are not known (DiTomaso et al., 2013).

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
Description

L. peploides is an emergent and floating herbaceous perennial macrophyte. It has glabrous or pubescent stems 1-30 dm that can creep horizontally as well as grow vertically. Early growth resembles a rosette of rounded leaves growing on the water’s surface. Alternate leaves are polymorphic and less than 10 cm long and oblong to round, often lanceolate at flowering. The species exhibits root dimorphism and has adventitious roots that form at nodes and ensure oxygen uptake. Flowers are 5-merous (pentamerous), grow from leaf axils, are bright yellow, and can be from 7 to 24 mm long. Fruit is in a five-angled reflexed capsule, about 3 cm long that contains 40-50 seeds 1.0-1.5 mm long, embedded in the inner fruit wall (EPPO, 2004;The Jepson Online Interchange, 2009).

Impact

L. peploides is a productive emergent aquatic perennial native to South and Central America, parts of the USA, and likely Australia (USDA-ARS, 1997). It was introduced in France in 1830 and has become one of the most damaging invasive plants in that country (Dandelot et al., 2008). It is often sold as an ornamental, which likely explains its introduction to Europe. It has been more recently introduced to areas beyond its native range in the USA, where it is often considered a noxious weed (INVADERS, 2009;Peconic Estuary Program, 2009). L. peploides is adaptable, and tolerates a wide variety of habitats where it can transform ecosystems both physically and chemically. It sometimes grows in nearly impenetrable mats;it can displace native flora and interfere with flood control and drainage systems, clog waterways and impact navigation and recreation (Peconic Estuary Program, 2009). The plant also has allelopathic activity that can lead to dissolved oxygen crashes, the accumulation of sulphide and phosphate, ‘dystrophic crises’ and intoxicated ecosystems (Dandelot et al., 2005).

Hosts

Impacts on the local environment by L. peploides can be devastating. The species possesses an allelopathic activity that has year-long effects on water quality and can lead to impoverished flora by decreasing seedling survival of vulnerable native taxa (Dandelot et al., 2008). L. peploides can also cause severe hypoxia and sometimes anoxia during the summer. It can also lead to reduced sulphate and nitrate levels and increased sulphide and phosphate concentrations. These combined effects have the capability of fomenting what Dandelot et al. (2005) refer to as “a dystrophic crisis” and an intoxicated ecosystem. The plant has been reported to outcompete native Myriophyllum and Potamogeton species in France, which translates to a reduction in macroinvertebrate habitat (Dutartre, 1986;CEH, 2007). It also supplants native wetland grasses, some of which are used as forage for livestock (CEH, 2007).


Source: cabi.org
Description


Grass species are notoriously difficult to identify. P. urvillei is a perennial grass that grows in clumps or tufts of a few to many stems growing from a short rootstock. The stems are purplish and hairy at the base but green and smooth towards the top;they are from 0.75 to 2.5 metres tall. The blades are green, vase-shaped, bristly and firm, 12 to 48 cm long (commonly 20 to 30 cm) and 3 to 15 mm wide;rarely, they can be up to 65 cm long and 2 cm wide. The inflorescences are 10-20 cm long, borne on a central axis 4-13 cm long. Each flower cluster bears six to 25 spikes. Four to thirty seedheads, grouped on spreading branches, have paired seeds lined up in 4 rows. Seeds are brown when mature and fringed with fine hairs, and may feel sticky. They characteristically lie on one side of the branch.

Impact

Paspalum urvillei is a well-known weed of agricultural fields and disturbed areas (Randall, 2012), but it has been widely introduced as a forage grass to ecosystems outside South America (Hitchcock, 1936;PIER, 2012;Bowen & Hollinger, 2002). It is now widely naturalized and is able to invade grasslands, shrublands and wetlands. It invades and establishes in highly disturbed natural ecosystems where it grows in dense stands, displacing indigenous vegetation and altering the lower strata (Western Australian Herbarium, 2012). It is listed as invasive in Portugal, Réunion, and the United States (NIISS, 2012;USDA-NRCS, 2012).

Hosts

P. urvillei often acts as an invasive agricultural weed (Randall, 2012). It is also a host of the rice stink bug Oebalus pugnax (Naresh and Smith, 1984), the Mexican rice borer Eoreuma loftini (Bezeulin et al, 2011), and the crop pathogenic bacterium Acidovorax avenae (Saddler, 1984);and it shows allelopathic activity (exudates) that can impact crop systems (Ishimine et al., 1987). Crops affected in one or more ways include rice Oryza sativa (Naresh and Smith, 1984;Bezeulin et al, 2011), sugarcane Saccharum (Bezeulin et al, 2011), maize (Zea mays), the fodder grass Hemarthria altissima (Newman and Sollenberger, 2005), Strelitzia nicolai, Sorghum spp., oats (Avena), millet, pineapples (González-Ibáñez, 1987), apples (Losso and Ducroquet, 1983) and citrus (Phillips & Tucker, 1974). P. urvillei is also an invasive weed of disturbed sites, footpaths, parks, gardens, turf, roadsides, waste areas, wetlands, watercourses (i.e. riparian habitats), open woodlands, closed forests and pastures as well as affecting the abovementioned crops (Queensland Government, 2012;Randall, 2012;Askew, 2012;Weakley, 2011;Quattrocchi, 2006;Motooka et al., 2003).


Source: cabi.org
Description


The following has been adapted from Wilken and Hannah (1998), Hoban and Hoshovsky (2000), Flora of North America (2016) and the Encyclopedia of Life (2016).

Impact

E. glomerata is a perennial herbaceous plant in the Asteraceae that is native to Australia and New Zealand and has become naturalised in northwestern USA (in the states of Washington, Oregon and California). It is considered a problem invader in the Channel Islands, California, USA. It is able to quickly colonise and dominate disturbed areas such as those cleared by logging activity or fire. Along with other non-natives, it is potentially threatening native species in California.


Source: cabi.org
Description

Culex quinquefasciatus is a medium-sized (approx. 4 mm) mosquito, predominately golden brown in coloration with solid coloured legs and a characteristic white-banded abdomen. The original type specimen collected from the Mississippi River in the southern United States by Thomas Say was lost but type specimens from C.R.W. Wiedemann’s 1828 description of Culex fatigans = quinquefasciatus still exist in the Naturhistorisches Museum of Vienna. A contemporary specimen of Cx. quinquefasciatus from New Orleans has since been designated as a neotype (Belkin, 1977).

Recognition


Surveillance for Cx. quinquefasciatus generally consists of dip surveys of all suspect larval habitats and selective trapping of adults using mechanized gravid traps baited with infusions of grass, manure or other organic matter (Reiter, 1983). Larval mosquitoes are often identified using morphological keys focused on chaetotaxy - the structure and arrangement of setae - of the siphon and terminal segments of the abdomen (Belkin, 1962;for more current terminology see Harbach and Knight (1980, 1981)). Morphological distinction of Cx. quinquefasciatus from related species is difficult at best but a number of rapid molecular diagnostic assays have been developed (Crabtree et al., 1995;Aspen and Savage, 2003;Smith and Fonseca, 2004).

Impact

Culex quinquefasciatus is a peridomestic mosquito seldom found far from human residence or activity, and readily feeds on avian, mammalian or human hosts. The larvae are typically found in the eutrophic water of artificial containers or man-made impoundments including open ponds, ditches and drains containing human or animal sewage. As such, Culex quinquefasciatus was uniquely adapted to the environs of historical sailing ships outfitted for long voyages where polluted water and livestock were common. Since adult mosquitoes can fly short distances to shore (Subra, 1981;LaPointe, 2008) and immature forms could be carried ashore in water casks taken to be refilled (Hardy, 1960), it is likely that this mosquito was spread worldwide by commercial sailing vessels involved in the Atlantic slave trade, Old China trade and American whale oil industry between the 17 and 19 th centuries (Lounibos, 2002). Today, adult Cx. quinquefasciatus are among the most commonly intercepted mosquitoes in passenger airline cabins and their larvae can still be found in exposed cargo (tyres and heavy equipment) and containers on modern ships (Joyce, 1961;Smith and Carter, 1984;Scholte, 2010).


Source: cabi.org
Activity Adelges tsugae
Description

Adelges tsugae is a small (0.74mm), reddish-purple, aphid-like insect that covers itself with a white, waxy secretion. Both winged and wingless forms are present. Their mouthparts are thread-like and about 1.5mm long and used to suck sap. Eggs are brownish-orange but darken as the embryo matures. When the eggs hatch, reddish-brown crawlers move about actively in search of a suitable site to settle. The tiny crawlers can only be seen with a hand lens as they are barely visible to the naked eye. Once the crawlers settle, they insert their mouthparts into the plant at the base of the hemlock needles and remain in the same place for the duration of their life. Dormant first instar nymphs are black with a white fringe around the edge and down the centre of the back. The developing nymphs produce white, cottony, waxy tufts that cover their bodies. The white masses are 3mm or more in diameter. The presence of these masses on the twigs and bark of hemlock is a sure sign of A. tsugae.

Impact

The hemlock woolly adelgid (Adelges tsugae) is a small, aphid-like insect that has become a serious pest of eastern hemlock and Carolina hemlock. The most obvious sign of infestation is the presence of white, woolly egg masses on the underside of hemlock needles. Infested eastern North American hemlocks defoliate prematurely and will eventually die if left untreated. A. tsugae is a difficult insect to control as the white waxy secretion protects it from pesticides. It is dispersed to new habitats through the nursery trade and locally by wind, birds, mammals and humans. Hemlock trees provide important habitats for many wildlife species and A. tsugae has severe adverse ecological impacts which will become more severe as its distribution expands. Explanations for the rapid and invasive expansion of A. tsugae include a lack of natural enemies, a lack of resistance or tolerance to infestation by eastern hemlock and Carolina hemlock, and large reproductive output (Trotter and Shields, 2009).

Hosts

Some of the adults produced during the spring generation are winged individuals that are unable to reproduce on hemlock, therefore they leave the hemlock tree in search of spruce, the alternate host. But because no suitable spruce host is available in North America, they soon die. Hemlocks growing in poor conditions (compacted soils, ledgy soils, poor drainage, drought prone, etc.) are much more likely to succumb within 3-5 years from invasion. Hemlocks growing under better growing conditions have been shown to withstand infestations longer.


Source: cabi.org
Description


Descriptions of L. trifolii refer to fresh materials. Dry specimens may be distorted due to the manner in which they have been preserved. Also, the age of the specimen, when killed, will have some effect on its preservation characteristics.
For accurate identification, examination of the leaf mine and all stages of development are crucial.
Egg
L. trifolii eggs are 0.2-0.3 mm x 0.1-0.15 mm, off white and slightly translucent.
Larva
This is a legless maggot with no separate head capsule, transparent when newly hatched but colouring up to a yellow-orange in later instars and is up to 3 mm long. L. trifolii larvae and puparia have a pair of posterior spiracles terminating in three cone-like appendages. Spencer (1973) describes distinguishing features of the larvae. Petitt (1990) describes a method of identifying the different instars of the larvae of L. sativae, which can be adapted for use with the other Liriomyza species, including L. trifolii.
Puparium
This is oval and slightly flattened ventrally, 1.3-2.3 x 0.5-0.75 mm with variable colour, pale yellow-orange, darkening to golden-brown. The puparium has posterior spiracles on a pronounced conical projection, each with three distinct bulbs, two of which are elongate. Pupariation occurs outside the leaf, in the soil beneath the plant.
Menken and Ulenberg (1986) describe a method of distinguishing L. trifolii from L. bryoniae, L. huidobrensis, and L. sativae using allozyme variation patterns as revealed by gel electrophoresis.
Adult
L. trifolii is very small: 1-1.3 mm body length, up to 1.7 mm in female with wings 1.3-1.7 mm. The mesonotum is grey-black with a yellow blotch at the hind-corners. The scutellum is bright yellow;the face, frons and third antennal segment are bright yellow. Male and female L. trifolii are generally similar in appearance.
L. trifolii are not very active fliers, and in crops showing active mining, the flies may be seen walking rapidly over the leaves with only short jerky flights to adjacent leaves.
Head
The frons, which projects very slightly above the eye, is just less than 1.5 times the width of the eye (viewed from above). There are two equal ors and two ori (the lower one weaker). Orbital setulae are sparse and reclinate. The jowls are deep (almost 0.33 times the height of the eye at the rear);the cheeks form a distinct ring below the eye. The third antennal segment is small, round and noticeably pubescent, but not excessively so (vte and vti are both on a yellow ground).
Mesonotum
Acrostical bristles occur irregularly in 3-4 rows at the front, reducing to two rows behind. There is a conspicuous yellow patch at each hind-corner. The pleura are yellow;the meso- and sterno-pleura have variable black markings.
Wing
Length 1.3 -1.7 mm, discal cell small. The last section is M(sub)3+4 from 3-4 times the length of the penultimate one.
Genitalia
The shape of the distiphallus is fairly distinctive but could be mis-identified for L. sativae. Identification using the male genitalia should only be undertaken by specialists.
Colour
The head (including the antenna and face) is bright yellow. The hind margin of the eye is largely yellow, vte and vti always on yellow ground.
The mesopleura is predominantly yellow, with a variable dark area, from a slim grey bar along the base to extensive darkening reaching higher up the front margin than the back margin. The sternopleura is largely filled by a black triangle, but always with bright yellow above.
The femora and coxa are bright yellow, with the tibia and tarsi darker;brownish-yellow on the fore-legs, brownish-black on the hind legs. The abdomen is largely black but the tergites are variably yellow, particularly at the sides. The squamae are yellowish, with a dark margin and fringe.
Although individual specimens may vary considerably in colour, the basic pattern is consistent.

Recognition

L. trifolii are small black and yellow flies which may be detected flying closely around host plants or moving erratically and rapidly upon the leaf surfaces. Inspection of the leaf surface will reveal punctures of the epidermis and the obvious greenish-white mines with linear grains of frass along their length. For accurate identification, examination of the leaf mine and all stages of development are crucial.
L. trifolii larvae will be found feeding at the end of the mine, or the mine will end with a small convex slit in the epidermis where the larva has left the mine to pupariate on the ground. Sometimes the puparium may be found adhering to the leaf surface, although in most cases the fully-fed larva will have found its way to the ground beneath the plant to pupariate. This is especially true in hot, dry conditions where the larva/puparia would quickly desiccate if exposed on the leaf surface. Empty puparial cases are split at the anterior end, but the head capsule is not usually separated from the rest of the case.
Mined leaves should be collected into polythene bags and transferred to a press as soon as possible. Leaves containing larvae intended for breeding should be collected into individual polythene bags, which on return to the laboratory should be slightly over-pressurized by blowing into them before sealing the end. Blowing up the bag by mouth and sealing it adds valuable carbon dioxide to the moist air mix. Constant attention is required to ensure that puparia are transferred to individual tubes until the fly emerges. If the plant material begins rotting, good material with feeding larvae must be removed to more sanitary conditions.
When puparia are observed they can be very carefully removed to tubes containing a layer of fine sand, or a small strip of blotting paper or filter paper. This should be kept damp (never wet) until the adult emerges.
On emergence, the fly should be kept for at least 24 hours to harden up. Do not allow condensation to come into contact with the fly, or it will stick to the water film and be damaged.
Field collection of the adult L. trifolii is done by netting. The use of sticky traps, especially yellow ones, placed near host plants is a very effective method of collection and estimation of infestation.
If the puparial stage is collected from the soil, care must be taken not to damage the puparial skin or death will almost certainly follow. The pupae should be stored in glass tubes on a layer of clean sand or, better still, thick filter paper. The tube must have high humidity, but be free of condensation.
When the fly emerges, it must be allowed to harden for 24 hours before killing for identification purposes. Ensure that the tube has no condensation present.
Newly emerged adult L. trifolii are generally softer than specimens aged for several days and may crinkle as drying proceeds, especially the head. The ptilinal sac may still protrude from the suture between the frons and face obliterating some important characteristics. Adults should be dried slowly in the dark in a sealed receptacle over blotting paper. If preserving wet is preferred, the live specimen should be dropped into 20-40% alcohol, and transferred to 70-90% alcohol after 2 days.

Symptons

L. trifolii feeding punctures appear as white speckles between 0.13 and 0.15 mm in diameter. Oviposition punctures are usually smaller (0.05 mm) and are more uniformly round.
L. trifolii leaf mines can vary in form with the host plant, but when adequate leaf area is available they are usually long, linear, narrow and not greatly widening towards the end. They are usually greenish white.
In very small leaves the limited area for feeding results in the formation of a secondary blotch at the end of the mine, before pupariation. In Kenya, Spencer (1985) notes the growth of many L. trifolii from mines which began with a conspicuous spiral. This is not a characteristic associated with L. trifolii on other continents.
The frass is distinctive in being deposited in black strips alternately at either side of the mine (like L. sativae), but becomes more granular towards the end of the mine (unlike L. sativae) (Spencer, 1973).
Fungal destruction of the leaf may also occur as a result of infection introduced by L. trifolii from other sources during breeding activity. Wilt may occur, especially in seedlings.

Hosts


The host range of L. trifolii includes over 400 species of plants in 28 families including both ornamental crops (Bogran, 2006) and vegetables (Cheri, 2012). The main host families and species include: Apiaceae (A. graveolens);Asteraceae (Aster spp., Chrysanthemum spp., Gerbera spp., Dahlia spp., Ixeris stolonifera, Lactuca sativa, Lactuca spp., Zinnia spp.);Brassicaceae (Brassica spp.);Caryophyllaceae (Gypsophila spp.);Chenopodiaceae (Spinacia oleracea, Beta vulgaris);Cucurbitaceae (Cucumis spp., Cucurbita spp.);Fabaceae (Glycine max, Medicago sativa, Phaseolus vulgaris, Pisum sativum, Pisum spp., Trifolium spp., Vicia faba);Liliaceae (A. cepa, Allium sativum) and Solanaceae (Capsicum annuum, Capsicum frutescens, Petunia spp., Solanum lycopersicum, Solanum spp.) (EFSA, 2012).
It is now considered to be the most important pest of cowpea (Vigna uniguilata), towel gourd (Luffa cylindrica), cucumber (Cucumis sativus) and many other vegetable crops in southern China (Gao, 2014). In Europe, L. trifolii is a major pest of lettuce, beans, cucumber and celery, Capsicum sp., carnations, clover, Gerbera sp., Gypsophila sp., lucerne, Senecio hybridus, potatoes and tomatoes (EFSA, 2012). It is now a major pest of the Compositae worldwide, particularly chrysanthemums (including Dendranthenum, the commercial 'Mum') in North America, Colombia, and elsewhere. It also causes severe damage to different open field crops, such as chili peppers in Mexico.


Source: cabi.org
Description


Eggs

Recognition


On both oil palms and coconuts, O. rhinoceros bores through the petiole bases into the central unopened leaves. This causes tissue maceration and the presence of a fibrous frass inside the feeding hole is an indication of its activity within (Catley, 1969). The adults may be forced out by 'winkling' with a hooked barbed wire into the feeding hole. Larval, pupal as well as adult population may be detected and inspected by digging into or breaking open its possible breeding sites its possible breeding grounds.

Symptons

O. rhinoceros adults feed in the crown region of both coconut and oil palm. On oil palms they bore through petiole bases into the central unopened leaves. This causes tissue maceration and the presence of a fibrous frass inside and at the entrance to the feeding hole is an indication of its activity within (Catley, 1969). A single attack may be followed by others on the same palm (Barlow and Chew, 1970;Young, 1975). These attacks subsequently produce fronds which have wedge-shaped gaps or the characteristic V-shaped cuts to fronds(Wood, 1968a;Sadakathulla and Ramachandran, 1990).

Impact

O. rhinoceros is included in the Global Invasive Species Database (ISSG, 2009).

Hosts


Primarily found attacking coconut and oil palm, O. rhinoceros has also occasionally been recorded on banana (Sharma and Gupta, 1988), sugarcane, papaya, sisal and pineapple (Khoo et al., 1991). In Mauritius, ornamentals such as the royal palm (Roystonea regia), the latanier palm (Livistona chinensis), the talipot palm (Corypha umbraculifera) and the raphia palm (Raphia ruffia) are attacked (Bedford, 1980).

Biological Control
Early attempts at biological control of O. rhinoceros concentrated on the introduction of predators and scoliid parasitoids of other Oryctes species mainly from Africa. None of those that became established was able to provide satisfactory control. However, biological control effort concentrated on Oryctes rhinoceros nudivirus (OrNV) after its discovery in Malaysia in 1965 (Huger, 1966) and its successful introduction into Western Samoa in 1967 (Swan, 1974;Waterhouse and Norris, 1987). Endemic natural enemies of O. rhinoceros offer a cheap and long-term control of the pest, leading to a reduction in the use of chemical insecticides. OrNV and the pathogenic fungus Metarhizium anisopliae have been utilized further for field control of this pest in several countries (George and Kurian, 1971;Latch and Falloon, 1976;Zelazny, 1979b;Bedford, 1986;Darwis, 1990). For OrNV, the adult beetles are dipped in a suspension of ground, infected grubs. They are then allowed to crawl about for 24 hours through sterilized sawdust mixed with the above suspension. They are then released back into the plantation to infect other adults and larvae in the breeding sites (Bedford, 1976d). OrNV suspension may also be applied directly to the mouthparts of adults to infect them for release (Ramle et al., 2005). A supply of beetles for infecting and release may be obtained from a mass-rearing facility. The fungus Metarhizium anisopliae var. major may be produced commercially or in bulk by various methods, for release by suitable means into breeding sites, particularly into chipped decaying oil palm trunk material in oil palm replant areas (Sivapragasam and Tey, 1995;Tey and Ho, 1995;Ramle et al., 1999, 2006, 2007, 2009, 2011;Ramle and Kamarudin, 2013).

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
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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
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Flowering stage, Fruiting stage, Seedling stage, Vegetative growing stage
Symptoms
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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
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Sign|Life Stages|Type
Leaves / internal feeding
Leaves / wilting
Leaves / yellowed or dead
Whole plant / early senescence
Biology and Ecology
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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
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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
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Latitude North (°N)|Latitude South (°S)|Altitude Lower (m)|Altitude Upper (m)
65
25
0
0
Rainfall
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Parameter|Lower limit|Upper limit|Description
Mean annual rainfall|430|1500|mm;lower/upper limits
Natural enemies
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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
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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
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Cause|Notes|Long Distance|Local|References
Crop production|| Yes
Yes
Spencer,
1973
Plant Trade
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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
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Category|Impact
Economic/livelihood
Negative
Economic Impact
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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
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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
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General
Laboratory use
Research model
Prevention and Control
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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

Evidence for a Viral Agent
A virus, BBTV, is the causal agent of bunchy top disease of banana. Although unequivocal evidence by reproduction of the disease through inoculation of purified virions or cloned genomic components is lacking, definitive association of BBTV with bunchy top disease was demonstrated by insect vector-mediated transmission of BBTV from an infected banana to a healthy banana plant. The virions are intimately associated with the disease (Harding et al., 1991;Thomas and Dietzgen, 1991) and have been detected in all symptomatic plants tested (Dietzgen and Thomas, 1991;Thomas, 1991;Thomas and Dietzgen, 1991;Karan et al., 1994;Kumar et al., 2011). Dale et al. (1986) and an published study (ML Iskra-Caruana, Montpellier, France) isolated dsRNA, suggestive of luteovirus infection, from Cavendish cultivars and from bunchy top affected plant samples. However, neither these, nor any subsequent studies, have identified or established a role for any virus other than BBTV in banana bunchy top disease aetiology.
Particle and Genome Properties
The virions of BBTV are icosahedra, ca 18-20 nm in diameter, have a coat protein of ca 20,000 Mr, a sedimentation coefficient of ca 46S and a buoyant density of 1.29-1.30 g/cm³ in caesium sulphate (Wu and Su, 1990c;Dietzgen and Thomas, 1991;Harding et al., 1991;Thomas and Dietzgen, 1991). Purified preparations have an A 260/280 of 1.33 (Thomas and Dietzgen, 1991). The virus possesses a multi-component genome, consisting of at least six circular, single-stranded DNA (ssDNA) components each ca. 1000-1100 nucleotides long, previously referred to as DNA-1 to -6 (Wu et al., 1994;Yeh et al., 1994;Burns et al., 1995;Xie and Hu, 1995). However, they were renamed as DNA-R, -U3, -S, -M, -C and -N. The DNA-R component encodes two open reading frames and other components each encode one protein (Burns et al., 1995;Dale et al., 1986;Beetham et al., 1997). Two areas of the non-coding regions are highly conserved between the six components (Burns et al., 1995). The first is a stem-loop common region of up to 69 nucleotides. It contains a nonanucleotide loop sequence conserved amongst ssDNA plant viruses and which may be involved in rolling circle replication and initiation of viral strand DNA synthesis. The second, 5' to the stem-loop common region, is a major common region varying in size between components from 65 to 92 nucleotides and which may have a promoter function. The initiation factor for endogenous DNA primers is also located within the major common region (Hafner et al., 1997a). DNA-R (c omponent 1) encodes a putative replication initiation protein and contains a second functional open reading frame internal to this, referred as U5, the function of which is unknown;whilst DNA-S (component 3) codes for the coat protein (Harding et al., 1993;Dale et al., 1986;Hafner et al., 1997b, Wanitchakorn et al., 1997). DNA-U3 (component 2) codes a protein of unknown function, DNA-M (component 4) codes for movement protein, DNA-C (component 5) has been shown to produce a gene product containing an LXCXE motif and to have retinoblastoma protein (Rb)-binding activity, known to perform cell-cycle-link protein, and DNA-N (component 6) codes for a nuclear shuttle protein. The gene product may be produced very early in the infection cycle and be responsible for switching the first infected cells to S-phase in preparation for virus replication. Recent research indicates that component 1 is the minimal replicative unit of BBTV and encodes the 'master' viral Rep (Horser et al., 2001a). Additional Rep encoding circular ssDNA components were reported in a few BBTV isolates from East Asia and the South Pacific region (Horser et al., 2001b). They were named BBTV-S1 and BBTV-S2, of 1109 and 1095 nts, and encoded a protein similar to the DNA-R segment but the genomic organization differed from that of DNA-R. The –S1 and –S2 components lack internal ORF U5, and the stem loop sequence was not similar to the six genomic components. These sequences were not considered as an integral part of the BBTV genome but the precise function of these additional DNAs was not known.
Strains of BBTV
Most isolates of BBTV are associated with typical severe disease symptoms. However, mild and symptomless isolates have been reported from Taiwan (Su et al., 1993;Djailo et al., 2016). BBTV has been confirmed in specimens of mild and symptomless infections from Taiwan by both ELISA and PCR (HJ Su, JL Dale and JE Thomas, Brisbane, personal communication, 1996) and the isolates can be transmitted by Pentalonia nigronervosa (HJ Su, Taipei, personal communication, 1996). Genomic differences, which correlate with these biological variants, have not yet been determined.
Two broad groups of isolates have been identified on the basis of nucleotide sequence differences between some, possibly all, of the six recognized genome components (Karan et al., 1994;Hu et al., 2007;Kumar et al., 2015;Qazi, 2016). The 'South Pacific' group (also referred as Pacific Indian Ocean (PIO) group) comprises isolates from Australia, Bangladesh, India, Myanmar, Pakistan, Sri Lanka, Fiji, Western Samoa, Tonga, Hawaii (USA) and all the isolates identified, as of 2017, in Africa (Angola, Benin, Burundi, Cameroon, CAR, Congo, DRC, Egypt, Equatorial Guinea, Gabon, Malawi, Nigeria, Rwanda, South Africa and Zambia), whilst the 'Asian' group (also referred as Southeast Asian (SEA) group) comprises isolates from China, Indonesia, Japan, the Philippines, Taiwan, Thailand and Vietnam. These differences are present throughout the genomes of components 1 and 6, but are most striking in the untranslated major common region. No biological differences have been associated with these sequence differences.
Magee (1948) noted that certain plants of 'Veimama', a cultivar originally from Fiji and growing then in New South Wales, showed a 'partial recovery' from bunchy top symptoms and produced bunches. After an initial flush of typical severe symptoms in three or four leaves, subsequent leaves showed few, if any, dark-green flecks. Suckers derived from these partially recovered plants also displayed a flush of typical symptoms followed by partial recovery. The origin of the infection, whether from Australia or Fiji, was uncertain. This partial recovery was noted for some infected plants of 'Veimama' only, and in Fiji was noted for one sucker only on a single infected stool from among hundreds of infected stools of 'Veimama' observed. Magee was not able to transmit the virus from partially recovered plants and was only able to super-infect them, with difficulty, with high inoculum pressure. This may be an example of a mild strain of BBTV, possibly a non-aphid transmitted one, propagated vegetatively, reaching only a low titre and conferring a degree of cross-protection. Alternatively, 'Veimama' may not be uniform and individual plants with a degree of resistance may exist. The complete explanation for this phenomenon is unclear. Evidence from recent studies suggests the occurrence of Musa cultivars with variable response to BBTV infection, ranging from extreme to moderate susceptibility and recovery associated with reduced virus titre (Ngatat et al., 2017;PL Kumar, IITA, Nigeria, personal communication, 2017). It is likely that previous observations of mild symptoms and lack of aphid-transmission may be related to virus-host interaction rather than to mild strains.
The inability to transmit bunchy top from abacá to banana (Ocfemia and Buhay, 1934) was originally considered evidence that two distinct strains of the virus existed. However, recent studies have identified a new virus, Abaca bunchy top virus (ABTV) which also belongs to the genus Babuvirus, as the cause of bunchy top-like symptoms in abacá (Sharman et al., 2008). The possibility of co-infection or single infection of BBTV and ABTV in abacá cannot be ruled out in endemic regions.

Symptons

The typical symptoms of bunchy top of banana are very distinctive and readily distinguished from those caused by other viruses of banana. Plants can become infected at any stage of growth and there are some initial differences between the symptoms produced in aphid-infected plants and those grown from infected planting material.
In aphid-inoculated plants, symptoms usually appear in the second leaf to emerge after inoculation and consist of a few dark-green streaks or dots on the minor veins on the lower portion of the lamina. The streaks form 'hooks' as they enter the midrib and are best seen from the underside of the leaf in transmitted light. The 'dot-dash' symptoms can sometimes also be seen on the petiole. The following leaf may display whitish streaks along the secondary veins when it is still rolled. These streaks become dark green as the leaf unfurls. Successive leaves become smaller, both in length and in width of the lamina, and often have chlorotic, upturned margins. The leaves become dry and brittle and stand more erect than normal giving the plant a rosetted and 'bunchy top' appearance.
Suckers from an infected stool can show severe symptoms in the first leaf to emerge. The leaves are rosetted and small with very chlorotic margins that tend to turn necrotic. Dark-green streaks are usually evident in the leaves.
Infected plants rarely produce a fruit bunch after infection and do not fruit in subsequent years. Plants infected late in the growing cycle may fruit once, but the bunch stalk and the fruit will be small and distorted. On plants infected very late, the only symptoms present may be a few dark green streaks on the tips of the flower bracts (Thomas et al., 1994).
Mild strains of BBTV, which induce only limited vein clearing and dark-green flecks, and symptomless strains have been reported in Cavendish plants from Taiwan (Su et al., 1993). Mild disease symptoms are expressed in some banana cultivars and Musa species. The dark-green leaf and petiole streaks, so diagnostic and characteristic of infection of cultivars in the Cavendish subgroup, can be rare or absent (Magee, 1953). Some plants of 'Veimama' (AAA, Cavendish subgroup), after initial severe symptoms, have been observed to recover and to display few if any symptoms.

Impact

BBTV is the most serious virus disease of bananas and plantains. It occurs in Africa, Asia, Australia and South Pacific islands. The virus is transmitted in a persistent, circulative, non-propagative manner by the banana aphid, Pentalonia nigronervosa, which has worldwide distribution. The virus is also spread through infected planting material. All banana cultivars are thought to be susceptible, with no known sources of resistance.

Hosts

In the Musaceae, BBTV is known to infect a range of Musa species, cultivars in the Eumusa (derived mainly from M. acuminata and M. acuminata x M. balbisiana) and Australimusa (derived mainly from M. maclayi, M. lolodensis and M. peekelii) series of edible banana and Ensete ventricosum (enset). Susceptible Musa species include M. balbisiana (Magee, 1948;Espino et al., 1993), M. acuminata ssp. banksii, M. textilis (abacá) (Magee, 1927), M. velutina (Thomas and Dietzgen, 1991), M. uranoscopos, M. jackeyi, M. ornata and M. acuminata ssp. zebrina (ADW Geering and JE Thomas, Brisbane, personal communication, 1998).
To date, there are no confirmed reports of immunity to BBTV in any Musa species or cultivar. However, differences in susceptibility between cultivars subject to either experimental or field infection have frequently been noted (Magee, 1948;Muharam, 1984;Espino et al., 1993;Ngatat et al., 2017).
Espino et al. (1993) evaluated a total of 57 banana cultivars for their reaction to bunchy top, both by experimental inoculation and field observations. All cultivars in the AA and AAA genomic groups were highly susceptible. However, low levels of infection (as assessed by symptom expression) or total absence of symptoms following aphid inoculation was noted in some cultivars containing the B genome. These included 'Radja' (AAB, syn. 'Pisang Raja' - 12.5% of inoculated plants with symptoms), 'Bungaoisan' (AAB, Plantain subgroup - 0%), 'Pelipia' (ABB, syn. Pelipita' - 10%), 'Pundol' (ABB - 0%), 'Katali' (ABB, syn. 'Pisang Awak' - 0%), 'Abuhon' (ABB - 0%) and 'Turangkog' (ABB - 0%).
These cultivars were not back-indexed by aphid transmission to a susceptible banana cultivar or tested biochemically (for example, by ELISA), so the presence of symptomless infection cannot be ruled out. Also, greater numbers of aphids than the 15 used here may have resulted in infection. Cultivars 'Abuhon' and 'Bungaoisan' are susceptible to BBTV by experimental aphid inoculation (ADW Geering and JE Thomas, Brisbane, personal communication, 1998). Nevertheless, it appears that real differences exist in cultivar reaction to bunchy top and the time taken before symptoms are expressed.
Evaluation of 16 Musa genotypes in Cameroon comprising plantain landraces, Cavendish bananas and synthetic hybrids revealed a high level of tolerance to BBTV in Gros Michel (AAA, Cavendish sub-group) and Fougamou (ABB cooking banana) (Ngatat et al., 2017). In another study of 40 Musa genotypes in Burundi, 8 genotypes (Musa balbisiana type Tani (BB), Kayinja (ABB), FHIA-03 (AABB), Prata (AAB), Gisandugu (ABB), Pisang Awak (ABB), Saba (ABB) and Highgate (AAA, Gros Michel subgroup)) were found to be asymptomatic, although Pisang Awak, Saba and Highgate tested positive to virus indicating tolerance to BBTV in some genotpyes (Niyongere et al., 2011).
Cultivars within the Cavendish subgroup form the basis of the international banana export trade and are generally highly susceptible to bunchy top. However, it appears that not all cultivars with an AAA genome are similarly susceptible. 'Gros Michel' exhibits resistance to the disease under both experimental inoculation and field conditions and Magee (1948) considered that the introduction of this cultivar to Fiji in the early 1900s contributed to partial rehabilitation of the bunchy top-devastated industry. Compared to 'Williams' (AAA, Cavendish subgroup), the concentration of virions of BBTV in infected plants of 'Gros Michel' and the proportion of plants infected by aphid inoculation is lower. Symptoms are also slower to develop and are less severe (Ngatat et al., 2017;ADW Geering and JE Thomas, Brisbane, Australia, unpublished, 1997). These factors may contribute to a reduced rate of aphid transmission and field spread in plantations of 'Gros Michel' (Ngatat et al., 2017).
There is no evidence for hosts outside the Musaceae, though reports have been conflicting. Su et al. (1993) obtained positive ELISA reactions from BBTV-inoculated Canna indica and Hedychium coronarium, and recovery of the virus to banana, though not reported here, was demonstrated (HJ Su, Taipei, personal communication, 1996). Ram and Summanwar (1984) reported Colocasia esculenta as a host of BBTV. However, Hu et al. (1996) were unable to demonstrate C. esculenta or Alpinia purpurata as experimental (E) or natural (N) hosts of BBTV in Hawaii. Geering and Thomas (1996) also found no evidence for the following species as hosts of BBTV in Australia: Strelitzia sp. (N), C. indica (E, N), C. x generalis (N), C. x orchiodes (N), H. coronarium (E), Helocania psittacorum (E), Alpinia coerulea (E, N), A. arundinelliana (E), A. zerumbet (E), Alocasia brisbaensis (E, N) or C. esculenta (E, N). Magee (1927) was unable to infect Strelitzia sp., Ravenala sp., Canna sp. (including C. edulis), Solanum tuberosum and Zea mays. Since the advent of improved and reliable diagnostics for BBTV, searches for alternative hosts outside the Musaceae, including those earlier suspects, have turned out to be negative.
Primary hosts are banana cultivars derived from M. acuminata and M. acuminata x M. balbisiana, and Musa textilis (abacá).


Source: cabi.org
Description


Slightly modified from Webb et al. (1988)

Impact

P. caerulea is a perennial vine native to South America (southern Brazil, Argentina, Paraguay and Uruguay), which has been deliberately introduced as an attractive flowering plant to many parts of the world. It has become established as an invasive species in New Zealand, Hawaii, offshore Chilean islands and possibly other Pacific islands. The species is considered valuable as an attractive ornamental vine, is reputed to have herbal activity as a sedative and anticonvulsant, and is often used as a relatively disease-resistant rootstock for the edible passionfruit (P. edulis). However, where it has escaped and become invasive, it can smother native species and suppress the establishment of native seedlings.

Hosts


The plants affected by P. caerulea are mostly native tree and shrub species in countries where it has escaped from gardens and become invasive.


Source: cabi.org
Description

Strains of P. parmentieri are Gram-negative, rod-shaped necrotrophs which destroy plant tissue components through the activity of plant cell wall-degrading enzymes such as pectinases, cellulases and proteases secreted via Type I or II secretion systems (Chatterjee et al., 1995;Liu et al., 1999;Charkowski et al., 2012) but lack the Type III secretion system (Kim et al., 2009). Pectinases (pectate and pectine lyases, polygalacturonases, methyl- and acyl-) and cellulases play a major role in the virulence of soft-rotting pathogens as they degrade the primary cell walls of infected plants. Proteases are also mentioned as they disrupt host plant protoplasts via degradation of transmembrane proteins (Marits et al., 1999). Effective spread of the pathogen through the plant's vascular system, often referred to as motility of the strain, is essential for the development of disease symptoms (Toth et al., 2003). The efficient production of iron scavenging molecules, siderophores, provides cofactors involved in almost all life-supporting processes (Ishimaru and Loper, 1992).

Symptons

Symptoms only appear on potato plants. Latent infection is common on potato tubers.
Potato blackleg mainly occurs from plants derived from latently infected seed potatoes. It is more severe when host resistance is impaired. Pathogenesis of P. parmentieri is also temperature dependent. Potato stem diseases generally develop under wet and partially aerobic conditions. Blackleg develops as a consequence of pathogen multiplication in rotting (or latently infected) mother tubers. Infection of seed tubers or stem invasion by P. parmentieri soon after emergence can result in blanking (rotting and death of the whole plant). Stunting, chlorosis and wilting symptoms, caused by restriction of water flow in the xylem vessels following infection, tend to develop at that stage under dry conditions (Pérombelon, 2002).
Potato soft rot during storage is usually a consequence of latent infection of potato crops. The bacteria are sited intracellularly, in lenticels and in wounds, typically beyond the phylloderm layer. Symptoms of soft rot exhibit as tissue maceration with intact skin of potato. A characteristic odor occurs when additional bacteria are present in infected tissue (Perombelon and Kelman, 1980;Pérombelon, 2000).

Impact

Pectobacterium parmentieri is a bacterial pathogen of potato present in Europe since the 1960s. The bacterium was earlier classified as Pectobacterium carotovorum. After reclassification of P. carotovorum subsp. carotovorum SCC3193 to P. wasabiae and later on to P. parmentieri, several studies devoted to identification of pectinolytic bacteria in international collections and identification of the strains isolated from infected potato plants have indicated that this bacteria commonly occurs in several regions of Europe, Canada, USA, New Zealand and South Africa. P. parmentieri can cause symptoms of blackleg and soft rot on potato tubers. These diseases are usually a consequence of latent infection of seed potatoes. In the majority of countries pre-basic and basic seed tuber potatoes intended for the production of seed tuber crops should be free of Pectobacterium spp. and Dickeya spp. P. parmentieri is not present on any international or national alert lists.


Source: cabi.org
Description

S. richteri (Order: Hymenoptera, Family: Formicidae), is a social insect that lives in colonies, usually associated with a mound. Most individuals are sterile female workers that perform a variety of functions, including care of the queen and brood, foraging, defense and nest building. The worker caste is polymorphic, ranging from small (minor) through intermediate (media) to large (major) individuals. Additionally, immature stages (eggs, larvae and pupae, or brood), winged reproductives and at least one queen will be present.
Colonies take approximately 2 years to mature and, on average contain, 200,000-400,000 individuals. Mature S. richteri colonies produce conspicuous mounds similar to those of S. invicta, averaging 30-50 cm in height and width, but they may be larger, reaching 90 x 90 cm. In hot dry conditions of late summer, S. richteri mounds may flatten out or disappear as the colony moves entirely underground. Mound building activity is stimulated by rainfall (Rhoades and Davis, 1967), and outbreaks have been found to be correlated with heavy precipitation, due to the queen’s needs for moist soil to excavate a nest (Green, 1962;Lofgren et al., 1975). Foraging worker ants enter and exit the colony through tunnels radiating up to 5-10m away from the mound. Colonies extend into the ground below the mound as interconnecting galleries, as much as 30-40 cm below ground level. In the USA, S. richteri colonies are usually found in open areas associated with some type of disturbance, e.g., lawns, hayfields, pastures, roadsides and highway medians, athletics fields, school grounds, etc. In their native Argentina, ideal habitats for S. richteri include the Pampas grasslands, as well as pastures of varying water content and seasonally waterlogged grassland (Taber, 2000). The disturbance of mounds results in a rapid defensive response by the worker ants, which will climb vertical objects in large numbers to bite and sting.

Recognition


Methods for detection of S. richteri are the same as those for S. invicta (see datasheet on Solenopsis invicta).
Visual inspection
Soil that is associated with any articles of trade or shipping equipment from areas known to be infested with S. richteri should be carefully inspected for the presence of ants. This could include various types of produce, turf and other nursery materials, honey bee equipment, hay, etc.
Foraging surveys
Baits are commonly used to survey for foraging activities of fire ant workers. A variety of food materials can be used, including sugar water, hot dogs, cookies, tuna, moistened pet food, etc. Baits are placed on or in such containers as petri dishes, plastic vials or test tubes, cardboard or laminated paper squares, etc. Under optimum conditions, fire ant workers will quickly find the baits and recruit other workers to them via trail pheromones. Baiting may be used by researchers to study ant behaviour, document impact of fire ants on other ant species, determine effectiveness of different control methods, time control applications, etc.
Monitoring fire ant mounds
Estimating the density of fire ant mounds in a given area is an easy way to quantify populations and monitor changes in population size in response to suppression measures. In addition to numbers, mound sizes and brood presence/absence can be used to further assess populations (e.g., see USDA mound rating system, Harlan et al., 1981). Some limitations to these methods include disappearance of mound structure in hot, dry weather, making detection more difficult ease of missing small, young colonies, location of fire ant colonies in areas not associated with a mound or hard to observe (e.g., tree stumps, hay bales), etc. Changes in populations through the year with changes in season usually necessitate sampling more than once to obtain reasonably accurate information.

Symptons


Information on crop hosts and feeding by S. richteri is limited, although S. richteri is known as a potato pest in Brazil (Taber, 2000). It is reasonable to expect similarities to S. invicta. S. invicta is omnivorous and foraging fire ants may be found in or on plants when they are preying on phytophagous arthropods associated with those crops. Plant feeding appears to be aggravated by dry or drought conditions. On other plants, the ants seem attracted to oil-containing plant parts such as the embryo portion of maize and sorghum seeds. Foraging workers on plants can become a hazard to field workers and tall, hardened mounds harbouring ant colonies in certain crops such as hay pastures or soyabeans can interfere with mechanized cutting and harvesting operations.
Affected plant stages include flowering stage, fruiting stage, post-harvest, pre-emergence, seedling stage and vegetative growing stage.
There is little or no specific information available on symptoms occurring in crops as a result of S. richteri feeding. In S. invicta, the following types of damage may be observed:
Fruits/pods: internal feeding;external feeding.
Leaves: wilting.
Roots: internal feeding;external feeding.
Seeds: internal feeding;external feeding.
Vegetative organs: internal feeding;external feeding.
Whole plant: plant dead;dieback;uprooted or toppled;internal feeding;external feeding
Biology and Ecology
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Genetics
In all ants, sex is determined by fertilization;unfertilized eggs produce males and fertilized eggs become females. Males occur only in the reproductive form, while females may become sterile workers or fertile reproductives (incipient queens). Whether a female becomes a worker or reproductive depends on its feeding and chemical (juvenile hormone and pheromones) environment (Tschinkel, 2006).
Two social forms are recognized in fire ants: monogyne colonies have a single functional (reproductively-active) queen, while polygyne colonies have multiple functional queens, ranging from 2-20,000 (Taber, 2000). Worker ants in monogyne colonies display territorial behaviour toward neighbouring colonies, whereas polygyne colony worker ants do not. As a result, polygyne colonies may have several-fold the number of ant mounds in a given area, sometimes reaching densities of several hundred mounds per hectare, 2-4 times the densities seen in monogyne areas (Porter et al., 1991;Porter, 1992;Porter et al., 1992;Fritz and Vander Meer, 2003). Polygyne fire ants are thus considered a greater economic and environmental threat than the monogyne form, although not as widespread. Polygyny is widespread only in S. invicta in the USA.
Polygyny exists in S.richteri in South America and is widespread there (Calcaterra et al., 1999;Briano et al., 1995). Apparently, only the monogyne form exists in the USA, although polygyny has been discovered in S. richteri / S. invicta hybrid populations (Glancey et al., 1989).
In the USA, S. richteri and S. invicta hybridize, resulting in an intermediate form that can produce fertile offspring. Polygyny has been reported in hybrids, but does not seem to be widespread. Currently, a broad band of hybridization between S. richteri and S. invicta exists from the Mississippi River to Atlanta, Georgia, occupying approximately 130,000 km 2 (Shoemaker et al., 1994).
Reproductive Biology
The S. richteri life cycle is similar to that of S. invicta (Taber, 2000). Winged reproductives form mating swarms and mating occurs in the air, after which the queen lands and sheds her wings;males die soon after mating. Several hundred virgin males and females may leave a colony at any one time. Mating flights can occur year round, especially in the native range in South America, but in North America often occur between April and August, usually on a warm, sunny day following rain. Following wing removal, queens establish colonies and start laying eggs. S. richteri queens establish their nests within approximately 3 cm of the soil surface, which is shallower than for S. invicta queens (Lofgren et al., 1975);however, the vast majority of queens perish before they can establish nests.
Once established, a queen at peak productive capacity can lay half her own weight in eggs daily and may live several years, until sperm depletion (Tschinkel, 2006). Before development of her first brood, the queen does not feed and must rely on stored food in the digestive tract and breakdown of flight muscles for nutrition (Taber, 2000). The queen loses a substantial amount of weight during care for the first brood. Eggs hatch into larvae, which pass through four instars;last stage larvae become pupae, which transition into adults. Workers, whether minor, media or major, change behavioural roles with age, first acting as nurses for queen and brood, then reserves (nurse + food reception from foragers) and, finally foragers. A new colony can start producing winged reproductives within 6-8 months, with production of several thousand individuals per year. It takes approximately 2 years for a colony to reach full maturity.
Physiology and Phenology
S. richteri is an adaptable species in a variety of ways, which contributes to its success. It is primarily a creature of disturbed habitats, both natural and manmade, in both its adopted and native countries (Tschinkel, 2006). It can aggressively exploit such areas, which is even more evident in S. invicta, allowing it to colonize and exclude other species that are potential competitors. The good fortunes of imported fire ants are closely tied to human activities, especially since the arrival of Europeans in the New World and the accompanying huge areas of ecological disturbance that resulted (Tschinkel, 2006). Fire ants are perhaps best viewed as pioneer species, evolved to exploit relatively rare and short-lived habitat patches derived from disturbance. They evolved high reproductive output as a response to dealing with such rare and unpredictable optimum habitat;effective dispersal mechanisms were also required to exploit habitats unpredictable in space. Additional adaptations to such habitats include rapid colony growth and early reproduction over a long season. Thus, fire ants have successfully exploited the highly disturbed landscape of the southeastern USA (Tschinkel, 2006). S. richteri produces a glycerol-type antifreeze which enables it to withstand colder temperatures than S. invicta, increasing its potential to move into habitats outside the range of S. invicta. Hybrid vigor associated with the S. richteri / S. invicta hybrid may also increase ability to withstand low temperatures (Callcott et al., 2000). S. richteri can readily adjust to varying environmental conditions, within limits, for example, moving brood around in mounds or underground to areas of optimum temperature and humidity. Its generalist feeding habits are an obvious adaptive advantage, allowing it to exploit habitats more efficiently.
Nutrition
S. richteri’s colony populations, foraging behaviours, diets and feeding behaviours are similar to those of S. invicta, which has been studied much more intensively (Taber, 2000;Tschinkel, 2006). Ants communicate through vision (sight), vibration (sound), touch and chemicals (pheromones), including a queen pheromone that attracts workers and a trail pheromone associated with the worker ant stinger. Upon locating food resources, a pheromone trail is produced which directs other worker ants to the site. Fire ants are omnivorous, consuming primarily other arthropods and honeydew produced by aphids and related insects (primarily Order Hemiptera, Suborder Sternorrhynca), but also seeds and other plant parts like developing or ripening fruit, and dead plant and animal tissues (Vinson, 1997). Living prey may be subdued by stinging. Foraging ants may bring solid or liquid food back to the colony;however, only certain larvae can process solid foods. Workers store liquid food in their crops, from where it can be regurgitated for nest mates (trophallaxis) (Glancey et al., 1981). Optimum ambient foraging temperatures range between 70 and 85 ° F (Rhoades and Davis, 1967).
Associations S. richteri symbionts have been studied in both South America and the southern USA. Caterpillars of the metalmark butterfly (Hamearis epulus signatus) spend much of their lives inside S. richteri mounds in South America, leaving the nest at night to feed on a leguminous host plant. When caterpillars are in the ant nest, workers feed on their bodily secretions. Other associates found in nests in South America included millipedes, short-winged mold beetles, seed bugs, lace bugs, wingless phorid flies, and rove beetles (Taber, 2000). One darkling beetle species native to South America, where it inhabits nests, is also found in the southern USA, although it has not actually been found in fire ant nests there (Taber 2000,).
Latitude/Altitude Ranges
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Latitude North (°N)|Latitude South (°S)|Altitude Lower (m)|Altitude Upper (m)
36
42
0
0
Air Temperature
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Parameter
Lower limit
Upper limit
Mean annual temperature (ºC)
15.2
20.4
Mean minimum temperature of coldest month (ºC)
0.8
9.3
Rainfall
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Parameter|Lower limit|Upper limit|Description
Mean annual rainfall|1011|1680|mm;lower/upper limits
Natural enemies
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Natural enemy|Type|Life stages|Specificity|References|Biological control in|Biological control on
Beauveria bassiana| Pathogen
All Stages| not specific
Burenella dimorpha| Pathogen
Caenocholax fenyesi
Adults| not specific
Kneallhazia solenopsae| Pathogen
All Stages| to genus
Argentina
Neivamyrmex opacithorax| Predator
Pachydiplax longipennis| Predator
Pseudacteon
Adults| to genus
Argentine, Brazil, Uruguay, USA (introduced)
Pseudacteon tricuspis| Parasite
Pyemotes tritici| Predator
All Stages| not specific
Solenopsis daguerrei| Parasite
Adults
Solenopsis molesta| Predator
Steinernema| Pathogen
Larvae/Pupae| not specific
Stichotrema wigodzinsky| Parasite
Vairimorpha invictae| Pathogen
All Stages| to genus
Notes on Natural Enemies
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There is a great deal of information available on imported fire ant natural enemies, including S. richteri, due primarily to the potential for biological control in areas where fire ants are invasive. The socially parasitic fire ant, Solenopsis daguerrei, was first discovered in S. richteri mounds in South America (Santschi, 1930). Colony parasitization rates in a given area can be as high as 31% and mound densities in affected areas are lower than densities where the parasite is not found (Calcaterra etal., 1999). Phorid flies in the genus Pseudacteon and several related genera produce larvae that decapitate worker ants and pupate inside their empty heads (Porter, 1998). Each species of fly parasitizes a characteristic size range of ants (Morrison et al., 1997;Morrison and Gilbert, 1999). Species that attack fire ants appear to be specific to fire ants (Porter, 1998). In addition to mortality, phorids appear to affect fire ant worker behaviour in important ways. Once flies are recognized, most ant workers seek cover, others curl into a stereotypical c-shaped defensive posture, and yet others freeze their posture (Porter, 1998). These behaviours generally result in reduced foraging rates;the presence of a single fly can stop or greatly inhibit the foraging of hundreds of workers within 2-3 minutes (Feener and Brown, 1992;Orr et al., 1995;Porter et al., 1995). In Argentina, the presence of six phorid species that attack S. richteri reduced the number of ants at food resources in the field, as well as foraging activity in general (Folgarait and Gilbert, 1999).

Impact

S. richteri is native to southeastern Brazil, central Argentina and parts of Uruguay. After its accidental introduction into the USA around 1918, it expanded its range into much of the southeastern USA and became a ubiquitous presence in a variety of urban and agricultural settings, as well as an important economic and environmental pest. However, the red imported fire ant, S. invicta, after its introduction through Mobile around 1930, gradually took over most of the range of S. richteri, and now occupies around 1,100,000 km 2, primarily in the coastal plains from N. Carolina to Texas (Porter and Briano, 2000). Currently, S. richteri is restricted to approximately 30,000 km 2 in northwestern Alabama, northeastern Mississippi and in parts of southern Tennessee, including a relatively recent introduction into Memphis (Jones et al., 1997). A broad band of hybridization zone between S.richteri and S. invicta exists between the two populations, occupying around 130,000 km 2 (Shoemaker et al., 1994). Comprehensive reviews of imported fire ants can be found in Lofgren et al. (1975), Taber (2000) and Tschinkel (2006). S. richteri is apparently more cold-hardy than S. invicta and thus has some potential to expand farther north, including possibly the southern Great Plains of the USA, which are similar to the South American Pampas, to which S. richteri is native. However, given human control efforts combined with intrusions of S. invicta and the S.richteri / S. invicta hybrid, it does not seem likely S. richteri will expand its range significantly in the future in the USA (Taber, 2000).

Hosts


Neither S.richteri nor S. invicta are considered major pests of crops although S. invicta is documented to feed on several crops, at times causing minor damage. S. invicta is well known to feed, and S. richteri workers probably feed, on honeydew produced by certain sternorrhyncan hemiptera (e.g., aphids, scale insects, mealybugs, etc.). Since the ants may protect these insects, their numbers may increase on some horticultural crops, especially if their natural enemies are reduced by fire ants.


Source: cabi.org
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