Invasive species

Q&A

Invasive species
Title: Morus alba
Description

A small to medium tree growing up to 15 m, M. alba has a short trunk, and a rounded crown with a dense canopy of spreading branches. Leaves are alternate, simple, 6-18 cm long, 5-13 cm wide, broadly ovate, dentate or lobed with 3 prominent veins running from the rounded or obliquely cordate base. Somewhat polymorphic, leaves are shiny green on the adaxial surface, paler and slightly hairy underneath. Bark is light brown to grey, smooth but may be furrowed. Dioecious, male inflorescences are small with 4 stamens, filaments inflexed in bud, green and borne on long catkins. Female flowers are inconspicuous, perianth with 4 free or almost free segments, aggregated in short spikes. Fruit is an ovoid or cylindrical syncarp composed of achenes, pendunculate, red when immature, blackish-purple, purple or greenish-white when mature, 1-2.5 cm long (Global Invasive Species Database, 2016, Tutin, 1964).


Source: cabi.org
Title: Morus alba
Invasive species
Title: Populus nigra
Description

P. nigra var. italica is a deciduous tree, with a narrow columnar crown. The trunk is straight with suckers at the base. The root system is lateral, shallow or deep, depending on soil layer and depth of water table, and can be invasive and problematical if trees are planted near buildings. The bark is more or less dark brown, thin and easily damaged.


Source: cabi.org
Title: Populus nigra
Description

H. flavescens is a c oarse perennial herb with thick fleshy rhizomes and erect, leafy p seudostems of 1-3 m in height. The leaves are sessile and have slightly pubescent sheaths. The ligule is 3-5 cm long and membranous. Leaf blades are elliptic-lanceolate or lanceolate, 20-50 cm long and 4-10 cm wide and abaxially (beneath) pubescent with attenuate base, membranous margins and a caudate-acuminate apex. Inflorescences are oblong spikes, 15-20 cm long and 3-6 cm wide;bracts are imbricate, oblong to ovate, 3-4.5 cm long and 2-4 cm wide, concave, 4- or 5-flowered. The bracteoles are tubular and membranous. Flowers are creamy-white to pale yellow or yellow-white in a cone like inflorescence, fragrant with yellow stamens. The calyx is 3.5-4 cm long, pubescent, approximately half the length of the corolla tube and almost as long as the bract. It is split on 1 side, apical margin entire. Corolla tube is 7-8.5 cm, long and slender. The lobes are linear, 3-3.5 cm long. The lateral staminodes are wider than the corolla lobes. The labellum is erect, creamy yellow with an orange patch at base, obcordate, longer than wide, and apex is 2-lobed. Filament is white to cream, subequaling labellum. Top of anther protruding slightly beyond lip. Ovary hairy. Stigma funnelform, margin bearded. Fruits are globose capsules 1-2 cm in diameter with three valves, containing numerous seeds but not seen in much of its invasive range.

Impact

A native of the Himalayas, H. flavescens has been introduced to many locations around the world as an ornamental and subsequently escaped cultivation to become a weed of significant economic importance in countries with favourable moist and warm climates. It threatens native forests in New Zealand, in La Réunion it outcompetes native plants and forms dense stands in wet areas such as ravine sides, roadsides, native forest margins and disturbed forests, and in Hawaii it tends to be confined to forest edges but also impacts negatively on the ecosystem. Its spread and dispersal is facilitated by vegetative regeneration of its dense rhizomes, which allows it to cover large areas of land and prevent the re-growth and establishment of native species, endangering rare and specialized plant communities. It is similar in its ecology and impacts to other invasive Hedychium spp., e.g. Hedychium coronarium and Hedychium gardnerianum.

Hosts

H. flavescens is not a weed of crops. It is an invasive species that threatens the environment, native communities and biodiversity.
Biology and Ecology
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Genetics
The chromosome number is reported to be 2 n=34.
Physiology and Phenology
H. flavescens, like its close relative, H. flavum, possesses large yellow inflorescences but can be distinguished from the latter by its hairier leaves and generally paler yellow flowers. The Zingiberoideae have a forced dormancy period during which all the above ground parts are shed and the plant overwinters as a thick, fleshy rhizome. Either just before or at the earliest signs of the wet season, individuals break dormancy with vegetative or reproductive shoots. Reproductive Biology
Spread in its invasive range is mainly by vegetative growth via rhizomes;however, in Hawaii some evidence exists that H. flavescens may be naturalizing by seed, though no fertile fruits have yet been found. Environmental Requirements
H. flavescens is a plant of the humid tropics, though being native to high altitudes, it can also tolerate cooler temperatures if in fully humid climates. It prefers areas with a mean annual rainfall of 1000-5000 mm, a mean annual temperature of 11-20ºC, and it can also tolerate frosts, though they may kill above-ground plant parts. H. flavescens requires medium to high soil fertility, and prefers to grow in open, light-filled environments which are warm and moist but will readily colonise semi and full shade under forest canopies. Altitude range in its native India is 1200-2000 m (Hooker, 1897;Mitra, 1958), 500-800 m in Sichuan, south-western China, below 2000 m Sri Lanka, and below 400 m in Hawaii but up to 2300 m where annual rainfall exceeds 1500 mm.
Climate
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Climate|Status|Description|Remark
Af - Tropical rainforest climate| Preferred
60mm precipitation per month
Am - Tropical monsoon climate| Preferred
Tropical monsoon climate (60mm precipitation driest month but (100 - [total annual precipitation(mm}/25]))
Cf - Warm temperate climate, wet all year| Preferred
Warm average temp. 10°C, Cold average temp. 0°C, wet all year
Air Temperature
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Parameter
Lower limit
Upper limit
Absolute minimum temperature (ºC)
0
-5
Mean annual temperature (ºC)
20
11
Mean maximum temperature of hottest month (ºC)
17
14
Mean minimum temperature of coldest month (ºC)
13
10
Rainfall
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Parameter|Lower limit|Upper limit|Description
Dry season duration|0|1|number of consecutive months with 40 mm rainfall
Mean annual rainfall|5000|1000|mm;lower/upper limits
Rainfall Regime
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Summer
Soil Tolerances
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Soil drainage
impeded
seasonally waterlogged
Soil texture
heavy
medium
Natural enemies
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Natural enemy|Type|Life stages|Specificity|References|Biological control in|Biological control on
Hypochniciellum ovoideum| Pathogen
not specific
Notes on Natural Enemies
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Due to its economic importance, the wide range of pests and diseases attacking cultivated ginger have been well researched. By contrast however, not much is known about the mycobiota and entomofauna of wild ginger species. Very few fungal pathogens had been reported on H. flavescens in its invasive range (Farr et al., 2008) although a strain of the soil-borne bacterium, Ralstonia solanacearum was isolated from Zingiber officinale (edible ginger) in Hawaii and caused no bacterial wilt in H. flavescens despite causing symptoms in H. gardnerianum and H. coronarium (Anderson and Gardner, 1999). The basidiomycete Leptosporomyces ovoideus was also recorded from H. flavescens in Hawaii (Farr et al., 2008).
Biological control options were subsequently investigated in New Zealand (Winks et al., 2007) following on from the research carried out in Hawaii. A survey of fungi, bacteria and invertebrates associated with H. flavescens (and H. gardnerianum) in New Zealand was carried out in 2006-07 for a national collective of regional councils and the Department of Conservation but no specialist agents were found. Furthermore, no isolates of R. solanacearum were found during the course of the surveys, even though it is recorded as present in New Zealand on other hosts, and it was concluded that the strain known to attack gingers was not established in New Zealand. Given the lack of specialist agents in New Zealand, recommendations were made that a classical control programme should be made, involving surveys in the native range of the wild ginger species of concern. A scoping survey to the Eastern Indian foothills of the Himalayas was carried out in 2008 by CABI scientists, sponsored by a consortium from Hawaii and New Zealand, and highlighted a large suite of damaging natural enemies associated with the Hedychium complex. Subsequent phases of the project have continued to consolidate and prioritise natural enemies for specificity studies, with the focus of the research being on H. gardnerianum, the most pernicious of the invasive complex.
A shoot borer (Conogethes puctiferalis) and a leaf roller (Udaspes folus) have been recorded from Hedychium sp. in India and several species of pathogens have been documented from Hedychium species including the basidiomycete, Lecanocybe lateralis Desjardin & E. Horak, from senescent leaves of H. flavescens (Indonesia) (Soares and Barreto, 2008) and Leptosporomyces ovoideus from H. flavescens in Hawaii (Gilbertson et al., 2002).


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


The shell of G. kibweziensis is translucent white, and dorso-ventrally distorted due to allometric changes during shell ontogeny. The juvenile shell is discoidal dome-shaped;the adult shell more globose and with the axis of coiling at about 13° angle to the axis of the juvenile. When the adult shell is examined in apertural view, the juvenile whorls sit atop and displaced to one side by the broader last two whorls of the adult whorls. Adult whorls with broadly rounded periphery. Aperture rounded, without barriers, with somewhat thickened and slightly reflected margins;parietal callus well developed. Umbilicus a minute perforation.The protoconch is smooth. The teleconch whorls are delicately ribbed.

Impact

G. kibweziensis is a non-specific predatory snail, taking a number of other snail species as prey. The species is not widely recognized as invasive. While it has become widely distributed in the islands of the Pacific and Indian Oceans as a biological control agent against giant African snails, continues to be spread in at least some regions by human agencies, and is known to interact with some native mollusc species, G. kibweziensis has not been unequivocally confirmed as threatening ecosystems, habitats or species or having major economic consequence.
Predation on native snails in regions to which G. kibweziensis has been introduced is undoubtedly occurring. Concern about G. kibweziensis effects on native land snail communities has been expressed in a number of countries to which the species has been introduced as a biological control agent, but definitive evidence for such effects is presently lacking. The use of generalized predators in biological control programs has long been recognized as unsafe due to expected environmental impacts, not least adverse effects on non-target species.

Biological Control
<br>Most natural enemies of terrestrial gastropods have proved not to be host-specific and therefore are not amenable for use in control programmes where effects on non-target species are of concern. To date, no natural enemy specific to G. kibweziensis is known.

Source: cabi.org
Description

The following description is from Flora of China Editorial Committee (2016)

Impact

D. bicornis is an annual, sometimes perennial grass. It is listed as invasive in North America (Mexico), Central America (El Salvador, Guatemala, Honduras, Nicaragua, Panama), the Caribbean (Cuba), South America (Colombia, Ecuador) and Oceania (Nauru, USA-Hawaii) (Catasús Guerra, 2015;PIER, 2016). It is considered as a weed in cultivated fields (Quattrocchi, 2006;Dias et al., 2007;Duarte et al., 2009;Catasús Guerra, 2015;Ramírez S et al., 2015).

Hosts

D. bicornis is a weed that occurs in maize, rice, soyabean and sugar cane fields (Quattrocchi, 2006;Dias et al., 2007;Ramírez S et al., 2015). Plants of maize and rice have been reported as being affected by downy mildew disease caused by Sclerophthora rayssiae that was acquired from soil where seedlings of D. bicornis were previously growing (Chamswarng et al., 1976).


Source: cabi.org
Description

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

Impact

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

Hosts

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


Source: cabi.org
Description

B. sylvaticum is a cespitose perennial bunchgrass that is sometimes very weakly rhizomatous. It ranges in height from a few centimeters up to about 200 cm. Sheaths are open and the nodes are typically pubescent. The leaf blades are bright green and remain green throughout the summer, even in dry Mediterranean climates (BA Roy, University of Oregon, USA, personal observation, 2009). The blades are 4-15 mm wide, flat and lax, with variable pubescence. Ligules are variable in size (1-6 mm) and are generally pubescent and ciliate. Plant size and pubescence depend both on habitat (Shouliang and Phillips, 2006) and genotype (Davies and Long, 1991). Racemes are nodding with an average of 9 spikelets, each with 3-24 florets. Lemma awns are 7-15 mm. Excellent full descriptions are published in the Flora of North America (Piep, 2003) and Flora of China (Shouliang and Phillips, 2006), both of which can also be found on line at www.efloras.org/index.aspx.

Recognition

For a grass, B. sylvaticum is relatively easy for botanists to identify because it grows in the shade of the forest (and often along trails, streams and rivers) and is quite pretty: it stays a bright vibrant green all season long, and has broad lax leaves and nodding inflorescences. Nonetheless, for identification it is best to involve a trained botanist as there are a couple of native forest grasses in North America with which it could be confused (for example, Bromus vulgaris, and possibly Melica subulata, Elymus glaucus and Bromus carinatus). Excellent identification information can be found at Piep (2003) and Shouliang and Phillips (2006).

Impact

B. sylvaticum is a bunchgrass naturally occurring in old world temperate forests and temperate zones of tropical Asian mountains. Its extensive native range includes most of Eurasia (e.g. Europe, Russia, China, Japan, India, Indonesia) as well as the Middle East (e.g. Lebanon, Syria, Iran) and North Africa (e.g. Algeria, Eritrea). It is invasive in North America (Piep, 2003), South America (Zuloaga et al., 1994), New Zealand (Edgar and Connor, 2000), and Australia (IBIS, 2009). It is shade tolerant (Murchie and Horton, 1998), spreads rapidly by seeds (Petersen and Philipp, 2001), has a persistent seed bank (Donelan and Thompson, 1980;Buckley et al., 1997) and is long-lived (Haeggström and Skytén, 1996). It forms monocultures and crowds out native plants and rare butterflies (Kaye and Blakeley-Smith, 2006;Severns and Warren, 2008). Furthermore, grasses significantly reduce recruitment of conifers (Powell et al., 1994;Lehmkuhl, 2002;Kruse et al., 2004). It is on noxious weed lists for three USA States: California, Oregon and Washington (CDFA, 2009;NWCB, 2009;ODA, 2009).

Hosts

The Pacific Northwest is world renowned for its timber production from conifers. It has not been established through a controlled study that B. sylvaticum in particular competes with conifers;however, several lines of evidence suggest that this grass will reduce survival and growth of conifer seedlings. First, a number of studies have established that the germination, growth and survival of conifers are negatively affected by competition with grasses (e.g. Powell et al., 1994;Lehmkuhl, 2002;Kruse et al., 2004). Second, at least one timber company (Starker Forests Inc.) has noticed that dense patches of false-brome provide safe cover for voles, which girdle conifer seedlings (G Fitzpatrick, The Nature Conservancy, Oregon, USA, personal communication, 2009). Third, none of the native grasses affected form a solid carpet in the forest, whereas B. sylvaticum does. These dense carpets will compete with seedlings in both logged and unlogged forests, and the build up of thatch may increase fire risk (Anzinger and Radosevich, 2008;False Brome Working Group, 2009). On the other hand, because B. sylvaticum remains green throughout the summer it may decrease fire risk (Anzinger and Radosevich, 2008;False Brome Working Group, 2009). These questions about fire need to be addressed with further research because this grass has the potential to cause ecosystem change if it alters fire behaviour.
The native grasses and herbs that live in the habitats being invaded are likely to diminish in cover and may face local extinction as a result of competition. A recent study showed that under shady high nutrient conditions, B. sylvaticum is a superior competitor to a native prairie grass (Festuca roemeri), a native forest grass (Elymus glaucus) as well as to another aggressive invasive Schedonorus arundinaceus (previously known as Festuca arundinacea) (BA Roy, University of Oregon, USA, personal observation, 2009). Two other grasses that occur sporadically in the forest (Melica subulata and Bromus carinatus) are also quite likely to be negatively affected. In its native range, B. sylvaticum is known for its ability to out compete other species due to its rapid relative growth rate (RGR) and ability to form persistent leaf litter (Grime et al., 1988;Haeggström and Skytén, 1996;Alonso et al., 2001).


Source: cabi.org
Description

Matthias et al. (2008) should be consulted for a description of P. dominula, but the following provides an introduction and is mainly based on this publication, unless otherwise stated

Recognition

Wegner and Jordan (2005) assessed three liquid lures for trapping social wasps, including P. dominula. They compared two citrus-based sodas and an isobutanol-acetic acid mixture, and reported that Polistes and Dolichovespula were found in significantly lower numbers than Vespula. However, they concluded that the citrus products were better than the known wasp attractant for attracting almost all of the wasp species.
In an earlier study by Landolt et al. (1999) in the USA, it was shown that the attractant properties of an isobutanol-acetic acid mixture varied according to location. Females of P. dominula were attracted to the mixture in Oklahoma.

Impact

P. dominula is a primitively eusocial paper wasp native to Mediterranean Europe. It is introduced and invasive in North America (Weiner et al., 2012). It is also naturalized in the Western Cape Province of South Africa (Veldtman et al., 2012).


Source: cabi.org
Description

V. velutina is highly variable in colour and 10 subspecies have been identified (https://www.cabi.org/ISC/datasheet/109164#232C47A5-7C02-427F-82E5-D5A688..." Vecht 1957;https://www.cabi.org/ISC/datasheet/109164#2C0D6014-E428-464E-A3BD-5BEF21..." Carpenter and Kojima 1997;https://www.cabi.org/ISC/datasheet/109164#01E52E03-1E70-4BB4-B22D-0D07CD..." Nguyen et al., 2006). The subspecies nigrithorax du Buysson (1905) is invasive in Europe, where it varies in size from 17 to 32 mm (Rome and Villemant, 2018).

Impact

Vespa velutina (Hymenoptera: Vespidae) is a hornet of Asian origin which is a generalist predator of medium- to large-sized insects, and scavenger of vertebrate carrion. It has large impacts on Diptera and social hymenopterans, and in particular on honey bees (Apis spp.). It has recently been spreading in Asia (it is an invasive species in South Korea and Japan), and the subspecies V. v. nigrithorax has been accidentally introduced to Europe where it was first recorded from southern France in 2005. Since then it has been found in Spain, Portugal, Belgium, Italy, the UK, the Netherlands, Germany, the Channel Islands and the Balearic Islands. This invasive species threatens honey production and native pollinating insects. It may be introduced and transported accidentally with soil associated with plants, garden furniture and pots, timber, vegetables, camping equipment, etc.


Source: cabi.org
Invasive species Acanthospermum australe Short, Long
Description


Annual or short-term perennial, stems 10-60(-120) cm, mostly procumbent. Leaves cauline. Leaves rhombic-ovate to triangular, 1.5-3.5 cm long, 1-3 cm wide, with conspicuous glands on both surfaces, margins irregularly serrate above the middle, base cuneate, petioles 0.3-1.5 cm long. Heads 4-6 mm in diameter, generally solitary, with 3-8 white-cream-yellow ray florets and 3-8 yellowish disc florets functionally staminate. The single-seeded fruits (cypselae) are each enclosed within and shed with an often hardened, ± prickly perigynium, ultimately plumply ellipsoid to fusiform, or ± compressed (PIER, 2015;PROTA, 2015;ZipcodeZoo, 2015).

Impact

Acanthospermum australe is a creeping annual or short-lived perennial plant, which originates from the tropics and sub-tropics of Central and South America. A. australe has been introduced to China, Australia, Africa, and the USA, where it is classed as invasive in the states of Hawaii and Oregon. It spreads to form dense mats that can smother other low-growing vegetation. In Australia, A. australe is seen as a threat to native mat-forming species in coastal sand dunes and in hind-dune vegetation. It is also regarded as an invasive species within its native range in Brazil, where it occurs in conservation areas.


Source: cabi.org
Description


The following description is taken from Flora of Pakistan (2015).

Impact

A. ochroleuca is an annual herb native to Central America. It has been introduced into Australia, Africa, tropical Asia, New Zealand and a number of oceanic islands where it has become invasive. It is most common in disturbed areas such as roadsides, mining dumps, rabbit warrens, recently cultivated paddocks, degraded land and over-grazed pastures. This species produces a large number of seed which can be accidentally introduced into new areas as a seed contaminant. It is often a problem in agricultural land but also has the potential to outcompete native species and decrease biodiversity. A. ochroleuca is toxic to humans and livestock and has thorny spines which can cause injury.


Source: cabi.org
Invasive species Adiantum raddianum, Adiantum Long, Short
Description

A. raddianum is a fern with a short-creeping and irregularly-branched rhizome up to 50 mm long and ca 2 mm wide. The rhizome and the bases of the frond stalks are covered with dark-brown scales of less than 1 mm length. Fronds are arched to erect, 10-50 cm long and 6-20 cm wide, and triangular in shape. Frond stalks and axes are dark reddish-brown to blackish and shining. The frond stalk is usually longer than the lamina. Laminas are 3-4-pinnately divided, with the ultimate segments delicate, herbaceous and up to 1 cm wide. Ultimate segments are wedge-shaped and have slender red-black stalks. Segments of sterile fronds, if present, are larger than fertile fronds. Spore cases (sori) are 'U'-shaped and arranged either at the edge of veins or at their tips and less than 4 mm wide. Each sorus is covered with a pale or whitish membrane (indusium).

Impact

A. raddianum is a delicate fern native to tropical and subtropical South America. The fern grows terrestrially or on rocks and erects arching fronds, up to 50 cm high, growing out of a short rhizome. The plant has become naturalized in various tropical and subtropical islands and is considered to be invasive in Hawaii and French Polynesia. The fern readily spreads and becomes locally abundant. In Hawaii it was first observed around 1910 and is now the most common Adiantum species. It grows best in moist and shady places and appears to replace the closely related native Adiantum capillus-veneris. It also threatens an endemic species of silversword, Dubautia plantaginea subsp. humilis, and another native fern, Pteris lidgatei.


Source: cabi.org
Invasive species Centella asiatica
Description


Adapted from Flora Zambesiaca (2014)

Impact

C. asiatica is a low-growing perennial with a pan-tropical distribution. It can spread to form a dense ground cover, desirable in some situations but unwelcome in others. It is recorded as invasive in a number of Pacific islands to which it has been introduced and is classed as High Risk (score 7) by PIER (2014), but the situations in which it is causing problems are not clear. It is not especially competitive in crops but may affect wild vegetation and biodiversity. C. asiatica is also among a number of species invasive in the Dongting Lake wetlands, Hunan province, China (Hou et al., 2011).

Hosts

C. asiatica is recorded as a weed in rice paddies, various plantation crops and forestry, but there are no indications of serious crop loss due to C. asiatica. Where it is listed as invasive, some native species are being impacted but little detail has been seen. In Hawaii, C. asiatica is among introduced species which have contributed to the decline of native sedges Carex thunbergii and Carex echinata (University of Hawaii, 1991).


Source: cabi.org
Invasive species Croton argenteus Documentation
Description

The following description comes from Burger and Huft (1995)

Impact

C. argenteus is an herbaceous weed of open sunny sites, pastures, and agricultural lands. It is also a common weed in rice plantations (González, 2000). Because this species grows in seasonally waterlogged areas, its seeds are often dispersed as a contaminant in dried and wet mud (Standley and Steyermark, 1946). Currently, it is listed as invasive only in Cuba, but it is a common weed in dry and wet fields in areas within and outside its native distribution range (Oviedo Prieto et al., 2012;USDA-NRCS, 2015).

Hosts

C. argenteus is a weed of pastures and rice and sugarcane plantations (Standley and Steyermark, 1946;González, 2000;Torres et al., 2010).


Source: cabi.org
Invasive species Cuphea carthagenensis, Cuphea Short, Long
Description


Annual herb to subshrub, many branched, erect to sprawling, 10-60 cm tall. Stem viscid-pilose, with intermixed glandular and non-glandular hairs. Leaves opposite, subsessile to short petiolate, elliptic, oval ovate, rarely obovate, with acute apex, 1.5-6 cm long. Flowers arising from leaf axils, solitary, 4.5-7 mm long, floral tube sparsely pubescent with glandular hairs, green, calyx lobes unequal, deltoid, short bristle-tipped, 6 petals, 2-3 mm long, linear-elliptic, pale purple, stamens longer than the floral tube. 3 seeds, 2 mm long, lenticular, olive to brown with pale edges (Graham, 1975).

Impact

Cuphea carthagenensis is an annual herb of moist habitats. Although its native range is uncertain, it is likely to cover parts of Central America and the Caribbean, and South America. It has become naturalized widely outside of its native range, in Central America, North America, the Caribbean, Oceania, and Asia. In its native and introduced range it is a weed of cultivated lands and disturbed sites, and sometimes invades intact natural areas in low densities. In Indonesia, where it dominates maize (Zea Mays), it is considered one of the top ten weeds (Solfiyeni et al., 2013). Several other species of Cuphea are also recorded as invasive (e.g. PIER, 2015).

Hosts

C. carthagenensis has been listed as a weed of a number of agricultural crops. In its native range in Brazil it is considered one of the most important weeds by (Pio, 1980) because of its abundance and competitive effects in Brazilian state of São Paulo, but which crops were affected were not specified. In Hawaii, USA, C. carthagenensis is a weed of cucumber (Cucumis sativus) (Valenzuela et al., 1994). In Assam, India, it is a dominant weed of rice (Oryza sativa) (Randhawa et al., 2006). In Indonesia, it dominates corn (Zea Mays) plantings (Solfiyeni et al., 2013). On Vanuatu, it is a serious pest of coconut (Cocos nucifera) groves and in pastures (Mullen, 2009). It is also a weed of taro (Colocasia esculenta) in Fiji (Heap, 2015) and of pastures (Robert, 1970). Laca-Buendia et al. (1989) reported it to be a sporadic weed of common bean (Phaseolus vulgaris) in Brazil.


Source: cabi.org
Description

E. paniculata usually grows as an annual or short-lived perennial plant. It is rooted in mud in shallow waterways. Submersed sessile leaves form a basal rosette and are linear to oblanceolate. Petiolate leaves are above the water surface with a cordate blade, acuminate to acute at the tip. Petiolate leaf blades grow 7.5-15 cm long, 3.5 – 9 cm wide, and the petiole may be up to 60 cm long. The flowers grow on separate flowering stalks in a panicle with 5-100 flowers developing over several days. The peduncle is sparsely glandular-pubescent to glabrous, 11.5-17.5 cm long;spathe linear, 13-35 mm long, the apex acuminate. Flowers are blue, white or lilac. The floral tube is 8-10 mm long, tepals are 12-15 mm long. The central upper tepal has two yellow spots toward the base. Upper and lower stamens are 2.5-3.5 mm and 5.1-8.5 mm long respectively. Stigmas are 3-lobed and tristylous. Seeds form in capsules 6-8mm long. Seeds are 0.6-1.0 mm long, 0.6-0.8 mm wide with 10-12 longitudinal wings (Barrett and Husband, 1997;Flora of the Guianas, 2016).

Impact

Eichhornia paniculata can grow in monocultural stands in shallow wetlands (Barrett and Husband, 1997). It is listed as a transformative species in Cuba by Oviedo-Prieto et al. (2012), although other sources suggest that it is native to Cuba (FreshFromFlorida, 2016). Listed as a prohibited aquatic plant in Florida along with all species of Eichhornia (USDA-NRCS, 2016), because of the invasive nature of other species in the genus. It appears to have naturalized only in Guyana (Funk et al., 1997) and is listed as an agricultural weed of rice fields in Jamaica and Cuba (Barrett, 2011).

Hosts

A weed of rice fields in Jamaica and Cuba (Barrett, 2011).


Source: cabi.org
Description


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

Recognition


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

Impact

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

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

Source: cabi.org
Invasive species Hyptis brevipes Long
Description

H. brevipes is an erect annual plant up to 1 m high with a square stem typical of the family, often densely hairy but sometimes less so. Leaves are also normally coarsely hairy on both surfaces, opposite, narrowly ovate or lanceolate, 4-7 cm long, up to 2 cm wide, cuneate at the base, the margins irregularly serrate. Apex acute to acuminate. The inflorescence is a dense raceme, almost globose, up to 14 mm diameter, on a peduncle about 1 cm long in the axils of most upper leaves. Corolla white or purplish-white, irregularly five-lobed about 5 mm long. The calyx, 4 mm long, also has 5 narrow, finely barbed lobes. Bracts lanceolate, 8-12 spreading or reflexed, 4-6 mm long, almost concealed by the flowers. Seeds ovoid, up to 1 mm long, dark brown to black, obscurely striate, with a conspicuous scar.

Impact

H. brevipes is an annual plant of cultivated land and wastelands, including forest edges, wet ground and rice crops, and is favoured by continuous wet conditions, without a prolonged dry season. It is native to Mexico, the Caribbean and much of South America and has been widely introduced across South East Asia, where it has naturalized. H. brevipes may be accidentally introduced into a new area as a contaminant of seed, in particular with rice. It has been listed as a ‘principal’ weed of Malaysia and a common weed of Borneo, Philippines and Taiwan (Holm et al., 1979). In addition, PIER (2017) report that H. brevipes is invasive in Singapore, Thailand and Vietnam. Lorenzi (1982) describes it as a damaging weed of humid conditions along the coast, where it can develop into large infestations. H. brevipes is typically a weed of agricultural land, causing yield losses and a negative economic impact.

Hosts

H. brevipes is primarily a weed of rice, especially in South East Asia, including Malaysia (Yong and Goh, 1977). In Indonesia it is noted to be a weed in rain-fed and upland rice fields, grasslands, rubber, cacao, young oil palm and sugar cane plantations and orchards (Knowledge Management Center on Topical Biology, 2017). It is also listed among weeds in mung bean in Indonesia (Bangun et al., 1986) and in Phaseolus beans in Brazil (Laca-Buendia et al., 1989).


Source: cabi.org
Invasive species Leptochloa fusca Short
Description


Perennial, loosely tufted to rhizomatous. Culms erect or geniculate and rooting from lower nodes, up to 100 cm or more tall. Leaf sheaths glabrous;leaf blades tough, usually involute, 5-30(-50) × 0.15-0.3(-0.6) cm, adaxial surface scabrid, abaxial surface subglabrous;ligule 3-12 mm, acute. Inflorescence 15-25 cm, scabrid;racemes 3-28, indistinctly unilateral, 4-20 cm, straight, ascending or spreading, spikelets usually distant. Spikelets glaucous-green, subterete, 6-14 mm, florets 5-12;glumes keeled;lower glume lanceolate, 2-3 mm, acute;upper glume narrowly oblong, 3-4 mm, acute or mucronate;lemmas narrowly oblong, dorsally sub-rounded, lowest 4-5 mm, lower lateral veins pilose, entire or 2-dentate, midvein often produced into a short 0.3-1.6 mm awn;palea ciliolate along upper keels. Callus laterally pilose. Anthers 0.5-0.75(-2.5) mm. Caryopsis elliptic-oblong, 1.5-2.5 mm, dorso-ventrally flattened. Flowers from June to September (based on description of L. fusca ssp. fusca from Flora of China, 2014).

Impact

L. fusca is a perennial weed with a global distribution. It is an aggressive species showing a competitive advantage in many situations due to its tolerance of saline and alkaline soils and its likely ability to fix nitrogen. It is commonly a serious weed of rice in many countries, and is of particular concern in Spanish rice fields. It is recorded as invasive on Hawaii and in the Chagos Archipeligo (as L. fusca ssp. uninervia) (PIER, 2014) and has been the subject of an ‘eradication action’ in Europe (Brunel et al., 2013).

Hosts

L. fusca (mainly ssp. fasciculari) is a major weed of rice in a number of countries including USA, Cuba and Spain. L. fusca ssp. fusca is also problematic in rice in India and other countries. It can also occur in lucerne/alfalfa, tomatoes and turf.


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
Invasive species Lygodium japonicum, Pinus Long, Short
Description

L. japonicum is a rhizomatous vine, climbing to 30 m. Rhizomes creeping, with black to reddish-brown hairs. Stipes spaced to 1 cm apart on rhizome. Rachis grooved, pubescent to glabrous, 3-30 m. Pinnae with short stalks, 3-5 cm. Pinnae deltoid shaped, 2-3-pinnate, to ca. 12 cm long, 12 cm wide, usually with a long central lobe, margins lobulate. Costae with scattered hairs, veins and pinnae surfaces typically glabrous, rarely with short hairs. Fertile segments with 3-5 separate lobes, subpalmate, sporangia born on sorophores, each with 4-8 sporangia pairs. Spore diameters 64-80 µm, averaging 76 µm.

Recognition


When mature, L. japonicum is easily detected on the ground due to its unique morphology and high-climbing habitat. However, because the species can disperse easily into remote areas via windborne spores new populations are easily overlooked because of difficulty of access.

Impact

L. japonicum is a high-climbing vine that has become established outside of its native range of Asia. L. japonicum is widely cultivated around the world. In the 1900s it became established in the south east USA and has since spread to at least nine states. L. japonicum occupies most of the southeastern coastal plain and parts of the Piedmont. Outside of its native range, L. japonicum has become an invasive species in a variety of habitats;floodplain forests, marshes and other wetlands, pine flatwoods, timber plantations and disturbed sites. It is a threat to natural areas where it outcompetes native species, alters fire behaviour and also poses an economic threat to the timber and pine straw industries. The distribution of the species continues to expand and could eventually occupy 39% of the USA;it has not yet reached the limit of distribution and abundance (USDA, 2009). Populations of L. japonicum have also become established on two Hawaiian Islands, Puerto Rico, Singapore and South Africa. Here, the species has not spread as aggressively as in the USA, but is of major concern.

Hosts


In the Philippines L. japonicum has been listed as a weed of upland rice (Moody, 1989;Galinato et al., 1999).
In southeastern USA it is an invader of pine plantations (Pinus spp.) (Beasley and Pijut, 2010).

Biological Control
<br>The potential for biocontrol of Lygodium species has been a subject of active research due to the invasiveness of two species in the genus in the USA: L. japonicum and L. microphyllum (Ferriter, 2001). While biocontrol agents have been released for L. microphyllum, no agents have been released specifically for L. japonicum. Finding a biocontrol suitable for this species will be difficult due to the sympatric, native species L. palmatum.<br>In 2005 a moth, Austromusotima camptozonale, was released in Florida for the control of L. microphyllum but failed to establish (Langeland and Hutchinson, 2013). A second species of moth Neomusotima conspurcatalis (Lygodium defoliator moth) was released in peninsular Florida in 2008 and 2009 as a biocontrol of L. microphyllum and populations have become established (Langeland and Hutchinson, 2013). This moth is genus specific and also feeds on L. japonicum, however, it is sensitive to cold temperatures. It was approved for release because of this characteristic as it will not pose a threat to the temperate native L. palmatum. While there are populations of L. japonicum in frost-free areas that will be impacted by N. conspurcatalis, populations outside of Florida will not be in the range of the moth (Madeira et al., 2008;Boughton et al., 2009). A second species in the genus, N. fuscolinealis, was also screened however it was rejected as it posed a threat to L. palmatum (Bennett and Pemberton, 2008).

Source: cabi.org
Invasive species Merremia aegyptia Long
Description

Herbaceous, twining or creeping vine, attaining 3 m or more in length. Stems cylindrical, usually reddish, with long, erect, yellowish, non-glandular hairs. Leaves alternate, 5-palmately compound;leaflets 4-14 x 2-6 cm, oblanceolate or elliptical, the apex and base acuminate, the margins entire and ciliate, hispidulous to glabrate on both surfaces. Flowers in dichasial cymes;peduncles shorter than the petioles, hairy;bracts deciduous;sepals subequal or unequal, 1.5-2 cm long, with long, yellowish hairs;corolla funnel-shaped, white, 2.5-3 cm x 4-4.5 cm;five stamens, white;stigma bilobed, white. Fruit capsular, 4-valvate, subglobose, 1-1.5 cm in diameter, light brown, glabrous, surrounded by the persistent sepals. Four seeds per fruit, obtusely triangular, 5-6 mm long, brown, glabrous (Acevedo-Rodríguez, 2005;Austin et al., 2012).

Recognition

M. aegyptia can be easily recognized in the field by the 5-digitate leaves with entire leaflets, and the long, erect hairs covering the stems and calyx.

Impact

Merremia aegyptia is an annual climbing herb that acts as a pioneer species in disturbed sites in tropical regions. It is considered a weed in most countries where it occurs and it has been included in the Global Compendium of Weeds as an agricultural and environmental weed (Randall, 2012). The species is native to tropical America and Africa and listed as invasive in Cuba, India, Australia and Hawaii.

Hosts

M. aegyptia is a relatively common weed in sugarcane (Brazil, Lesser Antilles, Reunion) and maize fields (Guatemala, Brazil, Nigeria), where it climbs up plants, bending and entangling their stems (Standley and Williams, 1970;Fournet and Hammerton, 1991;Lima e Silva et al., 2004;Valery, 2006;Chikoye et al., 2009;Correia et al., 2010;Correia, 2016). It has also been reported in cotton (Cardoso et al., 2010), banana (Isaac et al., 2009), rice (Ismaila et al., 2015), green pepper (Coelho et al., 2013), muskmelon (Teófilo et al., 2012), yam (Fournet and Hammerton, 1991) and coffee plantations (Gavilanes et al., 1988).


Source: cabi.org
Description

The following description is taken from Flora of North America Editorial Committee (2016)

Impact

N. lotus is a floating leafed macrophte and water lily, native to Africa and specific areas in Europe. It has a number of medicinal properties and is often introduced into new areas as an ornamental. This species has become naturalized in North America and some countries in South America and Asia, but no published reports of it being invasive were found other than presence (without further details) on an invasive species list for Louisiana (Louisiana Department of Wildlife and Fisheries, 2015). There are limited reports of the impact of this species, although in newly reclaimed wetlands in the Nile Delta, Egypt, N. lotus has been observed colonizing rice fields causing a significant decrease in growth and yield. Khedr and Hegazy (1998) describe it here as having "rampant behaviour as an aquatic weed invading the newly reclaimed ricefields," with its aggressiveness related to being able to spread through both vegetative and sexual reproduction.

Hosts

N. lotus is recorded as a weed in rice fields in Egypt where it can significantly reduce the growth and grain yield of the crop (Khedr and Hegazy, 1998;Hegazy et al., 2001).


Source: cabi.org
Description


Description taken from GrassBase (Clayton et al., 2006) with minor modifications from Godfrey and Wooten (1979) and from material reviewed by the author

Recognition


Separating P. geminatum from other tribes of grasses:
P. geminatum is perennial, does not form a winter rosette, and its basal leaves do not differ from stem leaves. The infloresence consists of several spike-like racemes along a main axis;rachis of racemes somewhat flattened, ending in a short, naked point (not a bristle);spikelets glabrous, fruits transversely rugose.
Separating P. geminatum from other Panicum in the tribe Geminata:
P. geminatum is glabrous throughout, nodes glabrous. Spikelets to 3.3 mm;glumes and sterile lemma not papery.
Determining P. geminatum:
The ligule is a ring of hairs to 1 mm long. Leaf sheaths compressed. Leaf blades flat medially, linear, the long-tapering tips involute;blades mostly glabrous or with minute hairs at base of upper surface. Infloresence up to 30 cm long and bearing 6 to 20 alternating, short-ascending or appressed-ascending flattish, spike-like fertile branches. The rachis is sharply 3-angled and ends in a short naked point, not a bristle. Spikelets planoconvex or nearly so, 2.2 to 3.3 mm long, arranged alternately in two rows on one side of the sharply 3-angled rachis. Spikelets are ovate to oblong-elliptic in shape. The first glume is short, as broad as it is long or broader than it is long.

Impact

P. geminatum is a globally-distributed grass that is an important component of marshes and emergent grasslands in tropical, dry, and warm temperate climates defined by well-marked dry and rainy seasons. P. geminatum contributes to unique and diverse wetland communities. It can become locally abundant under extended warm season flooding, but is not considered introduced, invasive, or problematic in these natural environments. P. geminatum has become problematic in arid climates where urbanization, irrigation and drainage projects have caused massive alterations in soil and hydrologic regime. It can spread through irrigation canals, open waste ditches and polluted riparian systems, compromising water flow and flood control.


Source: cabi.org
Invasive species Paspalum urvillei
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 description is from the Flora of China Editorial Committee (2016)

Impact

Erechtites hieraciifolius is a fast-growing, annual herb that is native to North, Central and South America and the Caribbean. It is recorded as an environmental and agricultural weed in areas both within and outside its native distribution. Mature plants can produce large amounts of wind-dispersed seed, facilitating the colonisation of new areas. It is adapted to grow in a wide range of disturbed anthropogenic habitats and can outcompete other species to form dense populations. It may also spread as a seed contaminant of crops. Currently, it is listed as invasive in Hong Kong, Hawaii, the Galapagos Islands, French Polynesia, Palau, US Minor Outlying Islands, New Zealand and Hungary. It is also considered a potential weed in Australia, where it is under quarantine.

Hosts

E. hieraciifolius has been listed as a weed of the following crops: oat (Avena sativa), barley (Hordeum vulgare), maize (Zea mays), strawberry (Fragaria ananassa), onion (Allium cepa), carrot (Daucus carota), cranberry (Vaccinium macrocarpon), blueberry (Vaccinium spp.) and sugarcane (Saccharum officinarum);it is also a weed of fodder crops (e.g. Medicago sativa) and of mixed pastures (Darbyshire et al., 2012).


Source: cabi.org
Invasive species Paspalum paniculatum Long
Description

P. paniculatum is a perennial grass;culms densely tufted, 0.3 to more than 2 m high, coarse, leafy, erect or ascending, sometimes decumbent at the base and rooting at the lower nodes, finally branching, the nodes glabrous to conspicuously bearded with stiff ascending hairs;sheaths mostly longer than the internodes, keeled, sometimes only on the collar and along the margins, colored orange-brown on the inner surface;ligule 1-3 mm long;blades 9-50 cm long, 6-25 mm wide, usually rounded at the base, densely hispid on both surfaces to nearly glabrous, with a tuft of long hairs on each side at the base, the margins scabrous;inflorescence 5-30 cm long, composed of 7-60 approximate, solitary or somewhat fascicled racemes, the lower ones 4-12 cm long, ascending or arcuate- spreading;spikelets paired, 1.3-1.5 mm long, densely crowded, the glume and sterile lemma equal, barely covering the fruit, softly pubescent, the sterile lemma woolly pubescent only on the margins;fruit about as large as the spikelet, smooth and shining (Flora of Panama, 2016).

Impact

P. paniculatum is a fast-growing grass sometimes used as an “auxiliary forage” crop (PROTA, 2016). Within and outside its native distribution, P. paniculatum behaves as an environmental and agricultural weed and can be found growing along roadsides, in disturbed places, moist shrublands, low open grounds, brushy slopes, forests, open ground, croplands and pastures (Zuloaga et al., 2003;Más and Garcia-Molinari, 2006;Más and Lugo, 2013;AusGrass2, 2016). Plants produce numerous seeds with germination rates higher than 85% (range: 86.5 to 99%, PROTA, 2016). Currently, this species is listed as invasive on Hawaii, Cuba, Trinidad and Tobago, Samoa, Northern Marianas Islands, Micronesia, Fiji, French Polynesia, New Caledonia, Niue, Palau and the Solomon Islands (Wagner et al., 1999;Oviedo Prieto et al., 2012;PIER, 2016;Trinidad and Tobago Biodiversity, 2016).


Source: cabi.org
Invasive species Artemisia biennis Long, Short
Description

A. biennis is an annual or biennial herbaceous plant. Stems are 1–3 m tall (although flowering plants may be as little as a few cm tall), erect and more or less spike-like, simple or somewhat branching at the base from a firm taproot. The stems are glabrous throughout, striate and often reddish.The leaves are alternate, glabrous, sessile, pinnatifid into narrow lobes with the lower leaf segments also pinnatifid, lobes of all but the uppermost toothed. Inflorescence a compound spike-like panicle, leafy throughout, with dense clusters of more or less globose capitula (flower heads) which are nearly sessile along short branches arising from upper leaf axils. Each flower head consists of a hemispheric involucre 2–3 cm long, made of 8–14 glabrous bracts. There are 6–22 or more outer pistillate (ray) florets, and 15–40 central bisexual disc florets. Corollas very small, pale yellow to whitish, with scattered stalked glands;corollas of the outer ray flowers about 1 mm long, somewhat tubular;those of the disk flowers bell-shaped, 1–2 mm long, with five triangular teeth. Cypselae (seeds) obovoid to ellipsoid, glabrous, lacking a pappus (bristles), very small (0.2–0.9 mm long), longitudinally 4-5 nerved and light brown.

Impact


The large seed production, small sticky seeds and adaptation to disturbed habitats facilitated the early and rapid spread of A. biennis beyond its natural range in North America, along transportation corridors and in association with human activities. In recent decades it has become invasive in some agricultural areas in North America. The increasing prevalence of A. biennis in agricultural lands seems to be associated with several factors, including: a shift to annual growth habit;increasing adoption of reduced tillage systems;crop diversification;and, a tolerance to several classes of herbicides. In Europe, the plant has become a local weed, but has not yet been reported as invasive in crops. However, increased frequency has been observed in some countries and changes in land use and agricultural practices suggest the potential for emerging problems in Europe in the future.


Source: cabi.org
Invasive species Frangula alnus
Description

F. alnus is a deciduous shrub or small tree usually 4-5 m in height (Tutin et al., 1968), but may grow to 7 m (Gleason, 1963). It develops an erect, slender habit with branches somewhat irregular in alternate pairs, ascending at an acute angle to the main stem (Godwin, 1943). Young twigs are green but turn grey-brown with age and develop red-brown to dark violet tips. Lenticels may be evident as white dots and stripes. Lemon-yellow inner-bark tissues are exposed when the outer-bark is damaged and the young wood is dark brown. Old bark is smooth, except in very old specimens, and readily peels off dead wood. Spines are absent from F. alnus. Leaves are petiolate, obovate in shape, 2-7 cm in length and usually little more than half as wide. They are cuspidate to acuminate in shape, typically ending with a short pointed tip. Leaf margins are entire but wavy, although in seedlings leaves may be serrated. The lower surface of young leaves is pubescent, being covered with dense brownish hairs which are later shed so that older leaves are glabrous and shiny green in colour. Sun leaves are relatively broader and more shiny than shade leaves. The leaves turn yellow, then red in the autumn. Lateral veins are conspicuous on the upper surface of the leaves with 6-12 (commonly 7) pairs running more or less parallel to each other.
F. alnus develops sessile umbels in the leaf axils on young wood with 2-8 flowers borne on stout, unequal, glabrous pedicels 3-10 mm long;occasionally single flowers develop. Individual flowers are greenish-white, about 3 mm in diameter and bisexual. The flowers are 5-merous with broadly obovate petals 1-1.4 mm long and cleft at the tip (Gleason, 1963). Fruits are 6-10 mm in diameter, and change from green to red, then to violet-black on ripening;flowering and fruit development are rather asynchronous, hence all stages of ripening may be present. Each drupe usually contains 2, but occasionally 3, pyrenes or stones which are broadly obovoid in shape, about 5 mm long and 2 mm thick;they have a faint ridge running down the inner face and a deep furrow at the base. Young and Young (1992) report 52 seeds/g for F. alnus. Germination is hypogeal (Godwin, 1943).

Impact

F. alnus was introduced to North America from Europe more than 100 years ago. Once established it maintains itself due to prolific seed production, vigorous growth over an extended growing season and its ability to regenerate following burning and cutting. These characteristics make it difficult to eradicate. Repeated cutting and application of herbicides required to eliminate F. alnus is laborious and expensive. Consequently, most restoration work has been conducted in natural ecosystems of special interest. Its adverse effect on native species arises because F. alnus shades out understorey plants. Its aggressive character, especially in wetlands, is widely noted (Catling and Porebski, 1994).

Hosts

F. alnus is a problem species in native communities because it establishes in dense stands which shade out other understorey species. Possessky et al. (2000) reported a reduction in composition and abundance of the herbaceous cover in riparian habitats in the northern Allegheny Plateau (of Pennsylvania, New York and Ohio, USA) following invasion by F. alnus. Similarly, Reinartz (1997) described how an undisturbed bog community in Wisconsin was invaded by F. alnus in 1955 with a dense tall shrub canopy dominating the site within 12 years. The species is listed as an invasive weed in Tennessee and Wisconsin, USA (Southeast Exotic Pest Plant Council, 1996;Hoffman and Kearns, 1997). F. alnus was recently rated as one of the six principal invasive aliens of wetlands in Canada, and one of four principal invasive aliens in Canadian uplands. In a national survey it was rated second to purple loosestrife (Lythrum salicaria) with respect to the extent to which it is spreading in natural habitats and its severity of impact in Canada (White et al., 1993).
F. alnus is associated with crown rust (Puccinia coronata) which infects several cool season turfgrasses, native grasses and cereals. The uredia, telia and basidiospores are produced on the graminoid hosts, the aecia and pycnia are produced on F. alnus (and Rhamnus cathartica;Partridge, 1998). Alfalfa mosaic virus, which infects a wide variety of plants, including crops, and is vectored by aphids, has also been isolated from young leaves and root cuttings of F. alnus in Italy (Marani and Giunchedi, 2002).


Source: cabi.org
Description


From PROTA (2013)

Impact

E. hypericifolia is a herbaceous shrub native to the Americas. It is regarded as an invasive weed in many of the Pacific Islands in which it occurs, especially Hawaii, where it is rated ‘high risk’. It is also a weed in Singapore and Taiwan, though the situations in which it is causing problems are not well documented. It is recognized as a weed in soyabean, sugar cane and cotton in some countries and is presumably also threatening native flora in others.

Hosts

E. hypericifolia is recorded as a weed in soyabean, sugarcane and cotton.


Source: cabi.org
Invasive species Merremia cissoides, Merremia Long
Description

Herbaceous, twining or creeping vine, attaining up to 6 m in length. Stems cylindrical, glandular- pubescent. Leaves alternate, 5-palmately compound;leaflets 1.5-7.5 x 0.7-3.5 cm, elliptical, ovate or ovate-lanceolate, the apex obtuse, the base acute or decurrent, the margins entire, undulate or dentate, glabrate or glandular-pubescent on both surfaces. Flowers in simple or double dichasial cymes;peduncles longer than the petioles;bracts persistent, linear to subulate;sepals subequal or unequal, 1-1.5 cm long, ovate to ovate-lanceolate, acuminate at the apex, glandular-pubescent;corolla funnel-shaped, white or sometimes pink, with or without a purple centre, 1.5-3 cm x 3-4 cm;stamens 5, white, sometimes with lilac anthers;stigma bilobed, white. Fruit capsular, 4-valvate, globose, 6-8 mm in diameter, light brown, glabrous, surrounded by the persistent sepals. Seeds 4 per fruit, ellipsoid, 5-6 mm long, dark brown, lanate (Acevedo-Rodríguez, 2005;Austin et al., 2012).

Impact

Merremia cissoides is a climbing weed native to tropical America that has been introduced to several Old World countries, presumably as an ornamental. It typically grows in disturbed areas and has been reported as a weed of several crops within its native range. However, it is not as widespread and common as other weedy species of Merremia. In several countries outside its native range, its occurrence has only been documented from one or few herbarium specimens. Nonetheless, the species is considered to be increasingly naturalized in the Old World tropics. It is invasive in Florida (USA) and Cuba.

Hosts

The species has been reported as a weed of sugarcane fields in Brazil (Perim et al., 2009;Correia and Kronka Júnior, 2010) and has also been reported in maize (Tavella et al., 2015), soybean (Timossi and Durigan, 2006), eucalyptus (Carbonari et al., 2010) and coffee plantations (Gavilanes et al., 1988).


Source: cabi.org
Description

D. caricosum is a perennial, stoloniferous grass. Culms tufted at nodes of stolons, geniculately ascending, 30–60 cm tall, nodes glabrous or pubescent. Leaf sheaths compressed, keeled, shorter than internodes;leaf blades flat, 15–20 cm × 2.5–5 mm, glabrous or with a few hairs at base, margins smooth or scabrid, apex acuminate;ligule less than 1 mm, margin ciliate. Inflorescence terminal;peduncle glabrous;racemes (1–)2–4, 2.5–5 cm, with 1–3 pairs of homogamous spikelets. Sessile spikelet 3–3.5 mm;lower glume obovate-elliptic or obovate-oblong, papery, 8–12-veined, glabrous or often sparsely hirsute on lower back, slightly glossy, margins shortly ciliate, keels winged, apex rounded;upper glume ciliate above middle, apex obtuse;awn 1.5–2.5 cm, weakly geniculate. Caryopsis obovate-oblong. Pedicelled spikelet many-veined, resembling sessile (Flora of China Editorial Committee, 2015).

Impact

D. caricosum has been intentionally introduced as a perennial grazing pasture with excellent ground cover. Now, it can be found widely naturalized in tropical and subtropical regions (Cook et al., 2005;FAO, 2015). It has escaped from cultivation and has become a weed and invasive grass in Cuba, Guam, New Caledonia, and Fiji (MacKee, 1994;Oviedo Prieto et al. (2012);PIER, 2015). In Cuba, it is widespread across the islands. In Fiji, it covers large areas being very common especially in the dry zones, in pastures, canefields, waste places, and along roadsides (Smith, 1979). D. caricosum is a fast-growing gregarious grass that competes aggressively with other plants including other weeds (Cook et al., 2005).

Hosts

D. caricosum is a common weed with negative impact in pastures and sugarcane fields (Smith, 1979).


Source: cabi.org
Invasive species Moorochloa eruciformis Long
Description

M. eruciformis is an annual terrestrial herb growing up to 45 cm tall and forming dense clusters of 10-60 cm long reclining and slender stems, with softly hairy culms rooting at the lower nodes. Stem internodes are hollow.

Impact

Moorochlora eruciformis is an annual herb, fodder crop and common agricultural weed, native to Africa, Asia and the Mediterranean;it has also been introduced to the Americas and Oceania. Crop seed contamination is a possible pathway for dispersal of this species. It is reported as invasive in Cuba, Spain and Australia as well as islands in Oceania. Despite this, there is limited information available about the economic and environmental impacts of this species or its dispersal potential.

Hosts

It is a common weed species in cultivated fields, particularly associated with maize, sugarcane and coffee crops (Holzner and Numata, 1982;Blanca et al., 2009;Afridi et al., 2015).


Source: cabi.org
Description


The following information is adapted from Puff (1991), Nelson (1996) and Wagner et al. (1999), and modified by the datasheet author using plant specimens from warm temperate (Jacono 952, FLAS) and subtropical (Howell 1285, FLAS) regions of Florida.

Recognition


Detection of P. foetida in the field or during inspection at ports of entry can easily be made based on the following features: a slender vine with opposite, oblanceolate, sometimes nearly heart-shaped, soft green leaves having a stipular tab on the stem between the petioles, the leaves producing a foul-smelling sulfurous odour when bruised, and fruits, if present, the size of a peppercorn, with a thin, brittle skin orange to brown in colour and splitting to release no more than two seeds.

Impact


A perennial vine of South-East and East Asian origin, Paederia foetida has characteristically opposite, soft and offensively smelling leaves, and produces solitary flowers and globose fruits in a ‘double scorpioid’ inflorescence. Vines trail across the ground, clamber over shrubs and twine into tree canopies to form curtains of dense vegetation that block light, provide undue weight, and offer a pathway for fire, often leading to the death of the host. P. foetida was introduced during the 19th century to the oceanic Mascarene and Hawaiian islands and later to the continental USA (Florida). It is regionally problematic in Florida where its distribution stands to expand internally and to other southern states. It is ranked by the Florida Exotic Pest Plant Council as a Category I (high impact) invasive species, invading and impacting natural areas, and is regulated as a noxious weed in both Florida and Alabama. In the Mascarene Islands it is a serious agricultural weed, and has recently become invasive in forest parks and disturbed urban sites in southern China.

Hosts

P. foetida has been and remains a principal weed of sugarcane on the island of Mauritius (Evans, 1947;Roghegouste, 1958). Changes over time in cultural practices, such as green cane trash blanketing, have favoured its more recent proliferation in sugarcane crops (Seeruttun et al., 2005). It is also well entrenched as a weed and contaminant in the Hawaiian nursery industry for ornamental foliage plants (Pemberton and Pratt, 2002).
P. foetida becomes a serious horticultural weed when it moves into lawns and yards in suburban Florida where little can be done to control it. Green, thin and pliable, its fast growing stems creep into lawn grass safely below the circulating blade of a lawn mower. The stems readily anchor themselves by rooting at the nodes that are continuously in contact with the ground. Stems can run from lawns into shrubbery, from where, after taking many twining turns around basal branches, the vines twist their way to the top of bushes and hedges, blanketing their surfaces and moving onwards to find the next vertical support.

Biological Control
<br>A 2010 survey in Thailand and Laos found insect herbivores associated with P. foetida and three other Paederia species. A leaf-tying moth, two hawk moths, a herbivorous rove beetle, a chrysomelid leaf beetle, a sharpshooter leafhopper and a leaf-sucking lace bug were the most damaging. The beetles were being investigated by the Hawaii Department of Agriculture as potential candidates for biological control of P. foetida in Hawaii (Ramadan et al., 2011). The survey included pathogens which were found in northern Thailand and were similarly taken to Hawaii for testing. One particular isolate of the fungus Colletotrichum gloeosporioides proved to be aggressive on P. foetida and, along with other fungi, is also under investigation for biocontrol purposes (Ko et al., 2011).<br>Many of the natural enemies of P. foetida so far identified and tested as potential biocontrol agents have been rejected as not having the required level of host specificity for safe use. For example, testing of Trachyaphthona nigrita and T. sordida in their native Japan indicated that they had Paederieae tribe-level feeding specificity and so were suitable as biological control agents (Okamoto et al., 2008), but when tested under quarantine conditions in Florida, USA, they showed significant feeding on native plant species of the tribe Spermacoceae. These flea beetles, therefore, lacked the appropriate level of host specificity (Pemberton and Witkus, 2011). Testing of Dulinius conchatus in Hawaii also showed lack of skunkvine specificity (Pemberton et al., 2005). In 2013 an Asian sawfly, Formosempria varipes, was discovered feeding on P. foetida in Hong Kong. Host preference trials undertaken in Florida showed, however, that several species of Paederia could serve as host plants, thus making it unsuitable for release as a biological control agent for P. foetida in that state (Smith et al., 2014).<br>In contrast, Ko et al. (2011) report that Endophyllum paederiae [ Puccinia paederiae ], a gall rust from Thailand infecting P. pilifera, would not accept P. foetida as a host in testing, apparently having too narrow a host range.

Source: cabi.org
Invasive species Passiflora suberosa
Description

P. suberosa is a herbaceous vine that clings to other vegetation by means of tendrils. The striated angled stems are glabrous or pubescent with corky bark. The leaves are highly polymorphic but tend to be deeply 3-lobed, 2.8-10.7 cm long (at most 14 cm) and 1.4-4 cm wide (at most 9 cm);sometimes entire rather than 3-lobed with 0.3-1.5 cm petioles, 2 paired-stalked 1 mm nectaries;the 3-4 mm stipules are linear-lanceolate. The white campanulate flowers with purple base are without petals, 0.5-2.4 cm in diameter with 5 greenish-yellow or white sepals. Peduncles (usually paired) are 0.9-1.7 cm long with a 1 mm hypanthium. Globose berries are 0.6-1.9 cm in diameter (about the size of a pea), and dark purple when ripe (Wagner et al., 1999). Individual vines tend to grow 60 cm or longer, but the plant can grow 6 m tall (Gann et al., 2011;Invasive Species South Africa, 2013).

Impact

P. suberosa is a herbaceous vine that clings to other vegetation by means of tendrils. Native to South and Central America, P. suberosa has become invasive on Pacific Islands in Melanesia and Hawaii and is also extending its invasive range through parts of Southeast Asia, Australia, India and Africa. (Its purple fruits are attractive to birds, which serve as vectors for its spread. As an herbaceous vine, it grows rapidly, smothering and competing with native vegetation, particularly in the sub-canopy (Biosecurity Queensland, 2007). Although its growth and rate of spread does not match the more aggressively growing Passiflora species, such as P. mollissima or P. foetida, it is nonetheless increasingly recognized as an undesirable weed through its damage to native forest species (Richardson, 2007;Bohm, 2012). It has also been recorded as invading sugar cane and Eucalyptus plantations (Seeruttun et al., 2005).

Hosts

P. suberosa is capable of smothering large trees (Mootooka et al., 2003). Although primarily an environmental weed, it has been reported to invade sugar cane and Eucalyptus plantations (Seeruttun et al., 2005). Despite not being as serious an invader as the congeneric P. mollissima (banana poka), P. suberosa can smother other native forest plants, and the thick, corky stems can impose additional weight on plants infested by the climber (Bohm, 2012).

Biological Control
<br>Ungulates browse P. suberosa vines to some degree, but systematic attempts have not been made to use ungulates to control growth (Blanfort and Orapa, 2008). No documented classical biological efforts involving insects have been attempted, although it is sometimes suggested that in areas where the plant is native, growth may be moderated by the presence of Lepidopteran larvae.

Source: cabi.org
Invasive species Thunbergia alata Long, Developed
Description

T. alata is an herbaceous vine, creeping or climbing, twining, 2-3 m in length. Stems cylindrical, slender, puberulous. Leaves opposite;blades 4.5-10.5 × 3.2-6 cm, ovate, lobed, chartaceous, the apex acute, the base subcordiform;upper surface dark green, dull, pubescent;lower surface pale green, dull, with prominent venation;petioles 4-8 cm long, winged, pubescent. Flowers axillary, solitary;pedicels pubescent, 4-5 cm long;bracts green, ovate, pubescent, 1.5 cm long, covering the calyx and the corolla tube. Calyx yellowish green, with 12 filiform lobes, approximately 4 mm long;corolla orange, pale yellow, or less frequently whitish, infundibuliform, with 5 lobes, the tube approximately 2.5 cm long, narrow at the base, dark violet inside, the lobes approximately 2.5 cm long with the apex truncate, the limb approximately 5 cm in diameter;stamens with glandular hairs on the basal portion. Capsules approximately 4 mm long, depressed-globose to 4-lobed at the base, the upper half in the form of a beak, dehiscent by two valves;seeds 2 or 4, 1.2-1.5 mm long, semicircular, reticulate (Acevedo-Rodríguez, 2005). Several cultivars have been developed, including some with white, yellow, and even pinkish-coloured flowers (Queensland Department of Primary Industries and Fisheries, 2011).

Impact

T. alata is an herbaceous vine, often cultivated as an ornamental, which has escaped and naturalized mostly in disturbed areas in tropical, subtropical and warmer temperate regions of the world (Starr et al., 2003;Meyer and Lavergne, 2004;Queensland Department of Primary Industries and Fisheries, 2011). It is a fast-growing vine with the capability of reproducing sexually by seeds and vegetatively by cuttings, fragments of stems and roots (Starr et al., 2003;Vibrans, 2009). Once established, it completely smothers native vegetation by killing host-trees, out-competing understory plants, and negatively affecting the germination and establishment of seedlings of native species (Starr et al., 2003;Meyer and Lavergne, 2004). T. alata is included in the Global Compendium of Weeds (Randall, 2012) and it is also considered an aggressive invasive plant in Australia, Japan, Singapore, Costa Rica, Cuba, Puerto Rico, Brazil, Colombia, Paraguay, and numerous islands in the Pacific including Hawaii and French Polynesia.

Hosts

T. alata is considered a weed affecting mostly plantation crops such as Citrus, coffee, mango, and banana plantations (Vibrans, 2009).


Source: cabi.org
Invasive species Psidium cattleianum
Description

The form of P. cattleianum trees depends on the environment. In full sunlight, it is a slow growing evergreen shrub, 2–4 m tall and often branching from the base with an overall round shape. Under shaded conditions, P. cattleianum is erect and branches weakly and can reach 8 m tall.
The slender stem and branches are smooth, pinkish, greenish or greyish brown in colour. Bark peels off in small papery flakes. Twigs are glabrous and cylindrical, and young leaves and twigs are red in colour. Leaves are opposite and decussate, shortly petiolate (petiole 3–10 mm long), elliptic to obovate, 4.5–12 cm long and 2–6 cm wide, with a blunt to slightly acuminate apex and a cuneiform sharp base. They are thick and coriaceous, upper surface dark green in colour, glossy, waxy, flat or slightly folded around the main rib. The lower surface is glabrous, whitish-green in colour, punctuated with small oil cavities (Arruda and Fontenelle, 1994), with the main rib prominent near the base but the 8–10 pairs of lateral ribs are not prominent, forming an intra-marginal rib 1–3 mm from the edge of the limb. Young leaves and twigs are red in colour.
The fragrant flowers are axillary and solitary, rarely grouped in 2 or 3. The four to five white petals are obovate, 5–6 mm long and wide. Flowers bear numerous stamens, 256 to 480 according to Raseira and Raseira (1996), and a greenish disc-shaped stigma. Ovary is tri- to pentalocular, mostly tetralocular. Fruit is a globulous to obovoid berry, 1.5–4 cm in diameter, bearing persistent sepals at the apex. The thin skin is dark green when unripe, and then red to purple for P. cattleianum var. cattleianum and sulfur-yellow for P. cattleianum var. lucidum. Pulp is soft, whitish, and contains several (2–100) seeds (Huenneke and Vitousek, 1990;Raseira and Raseira, 1996;Normand, 2002a). Seeds are reniform, 2–3 mm long, with a yellowish testa. Fruit has a pleasant, strawberry-like flavour when ripe, hence its common name.

Recognition


The use of remote sensing to map the introduction and spread of P. cattleianum in Hawaiian forests has been investigated (Barbosa et al., 2016). Use of airborne imaging spectroscopy followed by classification with a Biased Support Vector Machine framework is suggested as showing promise for detecting P. cattleianum invasion.

Impact

P. cattleianum is naturalized in many tropical and subtropical countries after introduction as an ornamental or a fruit tree. It has invaded humid areas such as rainforests on tropical islands especially in the Pacific and Indian Oceans where it displaces native species and threatens their survival. It thrives in a large range of ecological conditions and reproduces efficiently by seeds and suckers. Once established, it forms dense stands. This species shows allelopathic activity and its fruits host fruit flies (Motooka et al., 2003). Seeds continue to be available via mail-order on websites or seed catalogues, and the species will likely spread further.

Hosts

P. cattleianum is not a weed of crops but is an invasive species which threatens native forests and forestry plantations, and which has invaded meadows and pastures crowding out desirable forage plants (Hosaka and Thistle, 1954).


Source: cabi.org
Description


The following description is taken from Flora of China Editorial Committee (2015):
Annual grass, culms tufted, erect or geniculately ascending, slightly flattened, 15–100 cm tall. Basal leaf sheaths strongly keeled, glabrous;leaf blades flat or folded, 5–30 cm, 2–7 mm wide, glabrous, adaxial surface scabrous, apex acuminate;ligule 0.5–1 mm, glabrous or ciliate. Racemes digitate, 5–12, erect or slightly slanting, 2–10 cm, silky, pale brown or tinged pink or purple;rachis scabrous or hispid. Spikelets with 2 or 3 florets, 2-awned;lower glume 1.8–2.2 mm;upper glume 3–4 mm, acuminate;lemma of fertile floret obovate-lanceolate in side view, 2.8–3.5 mm, keel gibbous, conspicuously bearded on upper margins with a spreading tuft of 2.5–3.5 mm silky hairs, margins, keel and flanks silky-ciliate or glabrous;awn 5–15 mm;second floret sterile, oblong, glabrous, awn 4–10 mm;third floret occasionally present, reduced to a small clavate scale, awnless.

Impact

Chloris virgata is a widespread and very variable weedy annual grass (Flora of China Editorial Committee, 2015). This species is a particularly aggressive invader of bare areas and degraded or disturbed native vegetation, and it has the potential to out-compete native vegetation in these habitats (Smith, 2002;Oviedo Prieto et al., 2012;Weeds of Australia, 2015). This weedy grass spreads from cultivation, pastures, gardens, disturbed areas and roadsides to nearby disturbed forest, creeks and riversides, native grasslands and coastal habitats such as coastal forests and sand dunes (Weeds of Australia, 2015;FAO, 2015;PIER, 2015). It also grows as a weed in agricultural lands (Vibrans, 2009). Currently, this species is regarded as an invasive and environmental weed in northern Australia (i.e., Queensland and the Northern Territory;Weeds of Australia, 2015) and as an invasive grass in Cuba, Palau, New Caledonia, the Galapagos Islands, and Hawaii (Wagner et al., 1999;Charles Darwin Foundation, 2008;Oviedo Prieto et al., 2012;PIER, 2015).

Hosts

C. virgata is a common weed in alfalfa (Medicago sativa) fields of the southwestern USA (Barkworth, 2003) and maize and sorghum plantations in Mexico (Vibrans, 2009).


Source: cabi.org
Description

P. chinensis is a perennial herb. Rhizomes stout. Stems erect, 70-100 cm tall, ligneous at base, much branched, striate, glabrous or retrorsely hispid. Petiole 1-2 cm, usually auriculate at base, upper leaves subsessile;leaf blade ovate, elliptic, or lanceolate, 4-16 × 1.5-8 cm, both surfaces glabrous or hispid, abaxially sometimes pubescent along veins, base truncate or broadly cordate, margin entire, apex shortly acuminate;ocrea tubular, 1.5-2.5 cm, membranous, glabrous, much veined, apex oblique, not ciliate. Inflorescence terminal or axillary, capitate, 3-5 mm, usually several capitula aggregated and panicle-like;peduncle densely glandular hairy;bracts broadly ovate, each 1-3-flowered. Perianth white or pinkish, 5-parted;tepals ovate, accrescent in fruit, becoming blue-black, fleshy. Stamens 8, included. Styles 3, connate to below middle. Achenes included in persistent perianth, black, opaque, broadly ovoid, trigonous, 3-4 mm (Flora of China Editorial Committee, 2014).

Impact

P. chinensis is closely related to other important invasive Persicaria species such as P. orientalis, P. capitata, and P. perfoliata, all species included in the Global Compendium of Weeds (Randall, 2012). P. chinensis is a fast-growing herb that forms dense mats and tolerates diverse environmental conditions (Galloway and Lepper, 2010). It spreads by seed and by resprouting from broken fragments. Its high growth rates and spread potential provides this species the ability to smother other plants affecting plant community structure and composition (USDA-APHIS, 2012). Biosecurity New Zealand described the species in a risk assessment as “a highly invasive plant that quickly smothers available surfaces including other plants and trees,” and PIER (2014) lists it as invasive in several territories, including Hawaii.

Hosts

P. chinensis is a common weed requiring control in tea plantations where it covers tea bushes and blocks drainage systems (Tjitrosemito and Jaya, 1990).


Source: cabi.org
Invasive species Viguiera dentata Long
Description


Erect herbs to about 2 m high, the stems slender, sparsely strigillose or glabrate;lower leaves opposite, the upper alternate, petiolate, the blades ovate to rhombic-ovate or lanceolate, mostly 3-12 cm long, acute to long-acuminate, cuneate or attenuate to the petiole, the margins serrate, serrulate, or subentire, strigillose and usually scabrous above, beneath strigillose to densely soft-pilose;inflorescences pedunculate;heads on pedicels mostly 2-8 cm long, disposed in lax, open, cymose panicles;disc of the head 7-10 mm long, 10-14 mm broad;involucres broadly campanulate, 5-10 mm high;phyllaries 3-seriate, lance-ovate or ovate-oblong to linear or linear-oblong, acute or acuminate, herbaceous, spreading or appressed, hispidulous or densely appressed-pilose;ray flowers 10-12, the ligules yellow, 7-15 mm long;disc corollas yellow, more or less hirtellous, 3-4 mm long;achenes obovate-oblong, black or mottled, appressed-pubescent, 3-4 mm long;pappus a crown of fimbriate squamellae less than 1 mm long and 2 slender, unequal awns, 2.2- 2.8 mm long (Nash, 1976).

Impact

V. dentata is an erect herb listed as an invasive species only in Cuba (Oviedo Prieto et al., 2012). On this island, the species grows as an invasive weed in cultivated plots as well as in disturbed sites and ruderal areas. V. dentata also grows as a weed in ruderal areas and thickets within its native distribution range of Mexico and the USA (Vibrans, 2009;Flora of North America Editorial Committee, 2014;USDA-NRCS, 2014).


Source: cabi.org
Invasive species Filago gallica Documentation
Description

F. gallica is a densely hairy and greyish erect annual, up to 33(50) cm high, with alternate leaves;capitula in clusters, surrounded by linear to linear-lanceolate involucral leaves longer than the capitula.

Impact

Filago gallica is an annual plant native to Europe, Macaronesian Islands, northern Africa and southwestern Asia. It was introduced to North America (USA, Mexico), South America (Chile), India, Australia and New Zealand, where it has naturalized. F. gallica was listed as one of the most common plants of Mediterranean origin invasive in Californian rangelands by Houérou (1991), but currently there is little information indicating its invasive behaviour. It is not recorded as a noxious or (declared) weed in its introduced range of Australia, but F. gallica can behave as an agricultural or environmental weed (Randall, 2007).

Hosts


Within its native range of distribution F. gallica can be an agricultural weed (HEAR, 2015, HYPPA, 2015). F. gallica is an occasional weed of cereal crops, vineyards, olive groves and stone fruit orchards in Europe (France, Portugal and Spain) (Carretero, 2004;HYPPA, 2015).


Source: cabi.org
Invasive species Cenchrus biflorus Long
Description

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

Impact

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

Hosts

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


Source: cabi.org
Invasive species Euphorbia, Sonchus, Rumex, Artemisia
Description

S. junceum is a perennial shrub, 2-4 m tall. Slender stems erect with few branches. Stems cylindrical, rush-like, and green when young, maturing into woody branches. Mature plants have one to several trunks. Leaves are caducous, oblong-linear to lanceolate, 2-2.5 cm long, smooth-margined. Leaves are ephemeral, remaining on the plant for four months or less. Inflorescence is an open terminal raceme with several flowers. Flowers pedicellate, pedicels with a small caducous bract at base and two bracteoles at apex;corolla yellow, 20-25 mm long, anthers with a tuft of hairs at base. Fruit is a linear, dehiscent legume, 5-10 mm long and 5 mm wide, with 10 to 18 black seeds (Wagner et al., 1999;Zouhar, 2005).

Hosts

S. junceum negatively impacts populations of Corema album and Picconia azorica, two species listed as endangered in the Azores, as well as populations of the endemic species Erica scoparia subsp. azorica. Across the Canary Islands it affects populations of Aeonium ciliatum, an endemic species listed as vulnerable, as well as the following endemic species: Genista canariensis, Hypericum grandifolium, H. canariense, Andryala pinnatifida, Rumex lunaria, Artemisia canariensis, Argyranthemum frutescens, Euphorbia lamarckii, Sonchus acaulis, S. congestus, Micromeria varia and Adenocarpus foliolosus (Silva et al., 2008). Other species native to the Azores and the Canary Islands are also affected by the invasive nature of S. junceum (Silva et al., 2008).

Biological Control
In the USA, three insects have been introduced as biological control agents of broom species. Leucoptera spartifoliella (Scotch broom twig miner moth) and Exapion fuscirostre (Scotch broom seed weevil) are specific to Cytisus scoparius (scotch broom), but Bruchus villosus (Scotch broom seed beetle) also affects S. junceum (DiTomaso and Kyser, 2013).

Source: cabi.org
Invasive species Merremia tuberosa, Merremia Long
Description

M. tuberosa is a woody vine, climbing, twining, 10-15 m in length, with abundant milky latex. Stems thick, cylindrical, glabrous. Leaves alternate;blades simple, 7-12 × 6-11 cm, 7-palmatilobed, the lobes elliptical, long-acuminate at the apex, the base cordiform, the margins revolute, slightly sinuate;upper surface dark green, slightly shiny, glabrous, with the venation sunken;lower surface pale green, dull, glabrous or puberulous, with the venation yellowish, prominent;petioles as long as the blade, cylindrical, glabrous or puberulous. Flowers functionally unisexual, solitary or in simple dichasia. Calyx yellowish green, the sepals unequal, 2-3 cm long, fleshy, accrescent and woody once the fruit is formed;corolla yellow, infundibuliform, 4-5 cm long, the limb 4-5 cm in diameter;stamens exserted, the anthers white;stigma bilobed, green, exserted. Capsules ovoid, opening irregularly, 1.5-2.5 cm long, light brown, with the sepals persistent and accrescent at the base;seeds 4 per fruit, black, obtusely trigonal, 1-1.5 cm long, velvety (Acevedo-Rodriguez, 2005).

Impact

M. tuberosa is a woody vine commonly cultivated as an ornamental which has escaped from cultivation and has become naturalized mostly in wet, mesic, and lowland forests in tropical and subtropical regions of the world (Austin, 1998;Wagner et al., 1999;Acevedo-Rodriguez, 2005). M. tuberosa is a fast-growing vine with the capability to reproduce sexually by seeds and vegetatively from discarded cuttings (PIER, 2014). Once established, it completely smothers tall forest canopies, killing host-trees and out-competing understory plants (Smith, 1985). It is included in the Global Compendium of Weeds (Randall, 2012) and is also listed as invasive in Florida, Cuba, St Lucia, Hawaii, and on several islands in the Pacific Ocean (Wagner et al., 1999;Florida Exotic Pest Plant Council, 2011;Graveson, 2012;Oviedo Prieto et al., 2012;PIER, 2014).


Source: cabi.org
Description

S. glastifolius is an erect perennial herb, often with woody lower stems. Typically it grows to a height of about 1 m (Webb et al., 1988), but plants in sheltered conditions frequently grow to over 2 m tall. However, the majority of plants in the Manawatū region of New Zealand are 1.2 m tall, and it rarely reaches 2 m in Australia. Williams et al. (1999) report stems of 8 cm in diameter, but stems which are 9 cm in diameter at the narrowest point have been measured, with the base up to 11 cm diameter (G Rapson, Massey University, Palmerston North, unpublished data).

Recognition

S. glastifolius is extremely easy to detect during the flowering season, but is rather cryptic at other times, at least in New Zealand. Searching for new infestations or remnants is best done during the flowering period (early spring).

Impact

Senecio glastifolius is an erect perennial herb, native to the Eastern and Western Capes of South Africa. It is sold commercially as an ornamental and is often planted in gardens. It is known to have been introduced to Madeira, the UK and California in the USA and is recorded as invasive in Australia and New Zealand. It grows in shrubland and rocky, damp areas such as riverbanks. Where it is invasive, it grows in disturbed areas, agricultural land, open woodlands and coastal areas. In suitable habitats it is an extremely aggressive weed, producing large numbers of wind dispersed seed, and spreading rapidly, forming dense stands and potentially outcompeting native biodiversity. Ecological niche modelling revealed that, if introduced, this species could become invasive across large areas of the world including the west coasts of Canada, USA and South America and parts of Europe and Africa. Early detection and removal of seedlings, often garden escapes, is likely to be the most effective method of control. In New Zealand, infestations are largely controlled by hand-pulling of plants;however some commercially available herbicides have proved effective. The sale of this species has been banned in Tasmania, Australia and the Taranaki region of New Zealand.

Hosts

There are no known effects of this species on crops in New Zealand, as the plant is restricted to wasteland and coastal areas. It does occur among scrub in extensively grazed farmland, where it may eventually come to restrict productivity of preferred forage plants.

Biological Control
There are no known biological control agents for S. glastifolius (Froude, 2002). However, studies carried out by Brierley (1953) on the host range of chrysanthemum stunt virus found 39 plant varieties, including S. glastifolius, which were susceptible and developed recognizable symptoms.

Source: cabi.org
Description

U. gibba is an annual or perennial submerged or free-floating aquatic plant. Rhizoids absent or present, filiform, branched. Stolons filiform, much branched, often mat-forming. Traps lateral on leaf segments, stalked, ovoid, 1-2.5 mm, mouth lateral;appendages 2, dorsal, branched, setiform, with shorter setae. Leaves numerous on stolons, 0.5-1.5 cm;primary segments (1 or) 2, unbranched or sparsely dichotomously branched into 3-8 ultimate segments;ultimate segments capillary, slightly flattened, margin entire or sparsely denticulate, apex and teeth setulose. Inflorescences erect, 2-15 cm, 1-3(-6)-flowered;peduncle terete, 0.3-0.5 mm thick, glabrous;scale 1, similar to bracts;bracts basifixed, semiorbicular, ca. 1 mm, minutely glandular, apex truncate and obscurely dentate. Pedicel erect to spreading, 2-12 mm, filiform;bracteoles absent. Calyx lobes subequal, broadly ovate to orbicular, 1.5-2 mm, apex rounded. Corolla yellow, 4-8 mm;lower lip slightly smaller than upper lip, base with a prominent 2-lobed swelling, apex rounded;spur narrowly conic to cylindric from a conic base, shorter or longer than corolla lower lip, distal part sparsely stipitate glandular, apex obtuse;palate densely pubescent;upper lip broadly ovate to suborbicular, ca. 2 × as long as upper calyx lobe, apex obscurely 3-lobed. Filaments 1-1.5 mm, curved;anther thecae confluent. Ovary globose;style evident;stigma lower lip transversely elliptic, upper lip obsolete. Capsule globose, 2-3 mm in diam., 2-valvate. Seeds lenticular, 0.8-1 mm in diam., margin broadly winged, wing shallowly and irregularly dentate;seed coat with small prominent reticulations (Zhenyu and Cheek, 2011).

Recognition


An interactive key for invasive plants in New Zealand has been developed by Dawson et al. (2010).

Impact

U. gibba is an annual or perennial submerged or free-floating carnivorous aquatic plant. It has been identified as such a specialist invasive species and may outcompete native bladderworts in lowland wetland ecosystems in countries where it is introduced. It was intentionally introduced, as an aquarium plant, to New Zealand in 1980, where it is now fully naturalized.

Biological Control
Sclerotinia sclerotiorum (Lib.) de Bary, a naturally occurring pathogen of many weeds, has been tested on U. gibba but did not show any potential as a control agent (Waipara et al., 2006).

Source: cabi.org
Description


Following Hong (1993) and Alaska Natural Heritage Program (2011)

Impact

Persicaria wallichii is a shrubby perennial herb up to 180 cm tall that originates from the temperate, western regions of Asia and the Indian subcontinent. It is naturalized in Europe, Canada and the United States, where it was introduced as a garden ornamental. It grows vigorously and creates large and dense stands that exclude native vegetation and prevent tree seedlings from growing. P. wallichii can greatly alter natural ecosystems and promotes the erosion of river banks. It is reported as invasive in its native range in northern India (Kala and Shrivastava, 2004), as well as in its non-native range in Belgium and the UK (Rich and Woodruff, 1996;Branquart et al., 2007). In the western USA it is a declared noxious weed in the states of Montana, California, Washington and Oregon (USDA-NRCS, 2015).

Biological Control
<br>Goats have been reported to eat P. wallichii, and in some circumstances controlled goat grazing may be an option similar to intensive mowing. The disadvantage of this approach is that the goats will graze on desirable vegetation as well as P. wallichii (Soll, 2004).

Source: cabi.org
Description

P. perfoliata is a prickly scrambling vine. It can reach a height of 6 m or more through climbing over shrubs and understory trees. The stems are elongated, branched and furrowed with short recurved prickles along the ridges. The thin, papery leaves are triangular, about 3-7 cm long and 2-5 cm wide, glabrous on the upper surface with prickles along the mid-rib on the underside (Zheng et al., 2005). The circular, saucer-shaped leafy structures, called ocrea, surround the stem at nodes. The inflorescences are capitate or spike-like racemes up to 2 cm long with clusters of 10 to 15 tiny flowers either terminal or in the axils of upper leaves (Kumar and DiTommaso, 2005). The flowers, 1-3 cm long, are borne on racemes. The fruits are attractive, deep blue and arranged in clusters at terminals, each containing a single glossy, black or reddish-black hard seed called an achene (NPS, 2009). Roots are fibrous and shallow.

Impact

P. perfoliata is a fast growing, spiny and herbaceous vine. Like many other members of the genus Persicaria, the plant is an aggressive and/or invasive weed. The plant scrambles over shrubs and other vegetation, and blocks the foliage of covered plants from available light, thus reducing their ability to photosynthesize. The leaves, petioles, and stems of P. perfoliata contain prickles, causing the movement of wildlife, and human activities to be impacted in infested areas (Okay, 1997). In its native China the plant has been used in Chinese medicine for over 300 years (Lou et al., 1988) and has rarely been recorded as an important noxious weed in either agriculture or the environment (Wang et al., 1990).

Hosts

P. perfoliata is not generally a weed of agricultural land (Wang et al., 1990), as it is removed during cultivation. However, the plant can be a pest in orchards, climbing on and covering horticultural crops. In the USA, the plant has a negative effect on Christmas tree farms, forestry operations on pine plantations and reforestation of natural areas (NPS, 2009).


Source: cabi.org
Description

N. peltata is an aquatic, bottom-rooted perennial plant with round, floating leaves, yellow flowers borne upon peduncles rising above the water's surface, and long branching stolons with adventitious roots beneath the water’s surface. The circular to slightly heart shaped floating leaves are 3-15 cm in diameter on long stalks that attach to underwater rhizomes. The floating leaves have slightly wavy, scalloped margins and are alternately arranged at the stem base but are opposite at the apex (Flora of China, 2002). They are a green to yellow-green colour above, and are often a purple colour on the underside of the leaf. Each peduncle that rises a few inches above the water surface can have two to five flowers, which are bright yellow, have five distinctly fringed petals, and are 3-4 cm in diameter. Both long- and short-styled flower morphs are usually needed to sexually reproduce (Ornduff, 1966). The fruit is a 1.2-2.5 cm beaked capsule that contains many flat, smooth, ovoid seeds with winged margins. The seeds are approximately 0.4 mm thick, 3.8-5.1 mm long, and 2.7–3.0 mm broad (Cook, 1990). The seeds also have winged margins which aid attachment to avian vectors and floatation (Cook, 1990).

Impact

N. peltata is an aquatic, bottom-rooted perennial plant with floating leaves, which can grow in dense mats and reproduce prolifically through both vegetative and sexual means. These dense mats have caused many negative environmental and economic impacts, which include displacing native species, reducing biodiversity, decreasing water quality, impeding recreational activities, and diminishing aesthetic value. N. peltata is very difficult to control due to its ability to form a new plant from rhizomes, stolons, separated leaves, or seeds. The dispersal of N. peltata to new locations may be aided by the transport of seeds by avian vectors (Cook, 1990);however, the trade and potential escape of N. peltata through the water garden industry may play a larger role in its spread (Les and Mehrhoff, 1999). N. peltata is declared a noxious weed in New Zealand and parts of North America (NWCB, 2007), and is also declared as invasive in Sweden (Gren et al., 2007). Other species of Nymphoides also have the potential to become invasive, and N. indica and N. cristata have been recorded as problematic in Florida, USA.


Source: cabi.org
Invasive species Adiantum hispidulum, Adiantum Short, Long
Description


Terrestrial ferns, plants stiff, erect. Rhizomes erect to decumbent, short-creeping, with dark brown scales. Fronds clustered at apex of rhizome, erect, (6-)15–60 cm tall, young fronds rosy pink;stipes dark brown, rough, up to 30 cm long, clothed with short dark fibrils and hairs;blades ± fan-shaped, deltate to ovate, dichotomously branched at 45º angle into 7–15 branches;pinnules asymmetrically oblong-rectangular to diamond shaped, 0.5–1.7 cm long, 3–8 mm wide, the upper and outer margins gently rounded, finely toothed, the lower straight and entire, softly pubescent to ± glabrate, veins mostly ending in marginal teeth;pinnule stalks 0.5–1 mm long. Sori 6–14 per segment, small, closely placed on upper and outer edges in notches between the lobes;indusium flaps 3–4(–5) mm wide, circular to broadly oblong or kidney-shaped, covered with numerous small, pointed brown hairs (Verdcourt, 2002;Palmer, 2003).

Recognition


This species can be detected by visual identification, facilitated by using a reference book (Heath and Chinnock, 1974) or key (Palmer, 2003).

Impact

A. hispidulum, the rosy maidenhair fern, is known to be invasive and weedy in the main Hawaiian Islands where it has escaped from cultivation. In Hawaii it is a serious weed generally of mesic slopes and gulch bottoms and is often abundant along intermittent and perennial streams. It is capable of invading intact plant communities and pristine areas. A. hispidulum usually begins to colonize in areas where there is some type of natural disturbance such as landslides, tree falls, disturbance by feral ungulates, or even a single dislodged rock. The dense clumps and rhizome mats of this fern prevent establishment of many native taxa including rare species. A. hispidulum can also overrun other ferns and herbs (Wilson, 1996;Palmer, 2003;H. Oppenheimer, Hawaii Plant Extinction Prevention Program (PEP), USA, personal communication, 2013). It is naturalized locally in a few other parts of the world including the southeastern USA and parts of its native range including eastern and southern Africa, Malaya, and Singapore.


Source: cabi.org
Description

T. arguens is an annual, caespitose grass. Culms erect;20–120 cm long. Leaves mostly basal. Ligule an eciliate membrane;1 mm long. Leaf-blade base broadly rounded. Leaf-blades flat, or conduplicate;5–30 cm long;4–7 mm wide. Leaf-blade apex acuminate. Inflorescence composed of racemes;terminal and axillary;subtended by a spatheole. Spatheole lanceolate;2.5–3.5 cm long;scarious;without tubercles;glabrous. Racemes 1;single;cuneate;bearing few fertile spikelets;bearing 1 fertile spikelets on each. Rhachis fragile at the nodes. Spikelets in threes (basal paired). Fertile spikelets sessile;1 in the cluster. Companion sterile spikelets pedicelled;2 in the cluster. Pedicels oblong;1 mm long;tip oblique. Basal sterile spikelets represented by a single scale;4 in number;forming an involucre about the fertile;with both pairs arising at about the same level;subsessile;6–10 mm long;equaling fertile. Basal sterile spikelet glumes smooth;glabrous;lower glume muticous. Companion sterile spikelets well-developed;comprising 2 subequal glumes without lemmas;lanceolate;6 mm long;shorter than fertile;separately deciduous. Companion sterile spikelet callus linear;2–3 mm long;truncate. Companion sterile spikelet glumes herbaceous;glabrous;acuminate. Spikelets comprising 1 basal sterile florets;1 fertile florets;without rhachilla extension. Spikelets elliptic;subterete;8–10 mm long;falling entire;deciduous with accessory branch structures. Spikelet callus linear;3 mm long;bearded;base pungent;attached obliquely. Spikelet callus hairs red. Glumes dissimilar;exceeding apex of florets;firmer than fertile lemma. Lower glume oblong;1 length of spikelet;coriaceous;dark brown;without keels;7 -veined. Lower glume surface pilose;hairy above. Lower glume hairs dark brown. Lower glume apex truncate. Upper glume oblong;coriaceous;with membranous margins;3 -veined. Upper glume surface pilose;hairy above. Upper glume margins ciliate. Upper glume hairs dark brown. Upper glume apex truncate. Basal sterile florets barren;without significant palea. Lemma of lower sterile floret oblong;2.8 mm long;hyaline;ciliate on margins. Fertile lemma oblong;3 mm long;hyaline;without keel;1 -veined. Lemma apex entire;awned;1 -awned. Principal lemma awn apical;geniculate;50–70 mm long overall;with twisted column. Column of lemma awn hispidulous. Palea absent or minute. Anthers 1.4 mm long (Clayton et al., 2014).

Impact

T. arguens is a fast growing and very aggressive grass. At present, this species has been listed as invasive in Jamaica and Fiji, and it is spreading across these islands displacing and outcompeting native grasses and herbs (IABIN, 2014;PIER, 2014). In areas invaded by this grass, livestock tend to avoid it for more palatable species resulting in the dominance of T. arguens over other low growing species (Motta, 1953). In addition, T. arguens seeds heavily and seeds can be easily dispersed by wind, vehicles, animals, and attached to clothes and mud. The practice of using dry grass stems as packing for provisions being carried to market is another common cause for the introduction and spread of this species (Motta, 1953;PIER, 2014).


Source: cabi.org
Invasive species Lonicera confusa, Lonicera Long
Description

The following description is from Lim (2014)

Impact

L. confusa is a perennial vine belonging to the honeysuckle family and is native to China, Nepal and Vietnam. It has long been used in traditional Chinese medicine. It is listed as an invasive species in Cuba and is also reported as one of the 46 most widespread invasive plants on the island of Réunion in the Indian Ocean. Despite this, there is no information available about its economic, social or environmental impacts or any methods for prevention or control of the species.


Source: cabi.org
Invasive species Lonicera maackii, Lonicera Long
Description

L. maackii grows to be a tall shrub, up to 6 m high. The leaves are opposite, lightly hairy, and have long, acuminate tips. The leaves range in length from 5-8 cm and are dark green above, paler beneath. Pairs of fragrant, tubular, white to pinkish flowers, fading to yellow bloom from the leaf axils in mid to late spring. Bright red fruits 5-6 mm in diameter mature from late summer into autumn (Zheng et al., 2006). The bark is a light grayish brown on mature stems.

Impact

L. maackii is a species of honeysuckle native to East Asia and primarily invasive in central and eastern USA and in Ontario, Canada. It grows as a tall, deciduous shrub in dense stands along woods edges, in disturbed forests and along riparian corridors, outcompeting native species for resources. Few insects feed on the plant, but birds and mammals spread the fruits. It may have allelopathic affects on neighboring plant species. L. maackii was heavily promoted and planted from the 1960s to the 1980s in the USA, but its popularity has since declined. It is still available for sale at some nurseries and online. It is listed as a Class B Noxious Weed in Vermont and sale and planting are prohibited in Connecticut and Massachusetts, USA. L. maackii is critically endangered in parts of its native range in Japan.

Hosts


Under experimental conditions, extract of L. maackii showed allelopathic affects against seeds in the Brassicaceae family, but no crop species were tested (Cippolini et al., 2012).

Biological Control
<br>No known biological controls exist (Batcher, 2000). A study of fungi and arthropods on in China identified several species that live or feed on L. maackii (Zheng et al., 2006). Few North American insects feed on L. maackii enough to impact its growth (Lieurance and Cippolini, 2012;2013).

Source: cabi.org
Invasive species Lonicera morrowii, Lonicera Long
Description

L. morrowii is a deciduous, woody shrub with hollow stems and brown or grey bark that is ridged and peels off easily (Go Botany, 2018). It grows up to 2.4 m tall (Invasive.org, 2018). It has simple, untoothed, elliptical or oblong leaves that are 25-50 mm long, with two leaves per node (Go Botany, 2018). Leaves are hairy underneath and hairless or sparsely hairy on the upper surface (Go Botany, 2018). They are greyish and tomentose on the lower surface (IPANE, 2018) and have one main vein running from the base towards the tip, with secondary veins branching off at intervals (Go Botany, 2018). Peduncles are 5-15 mm and very hairy, and bractlets, sepals and corolla are also covered in downy hair (IPANE, 2018). Winter buds have three or more scales that overlap like shingles, with one edge covered and the other exposed (Go Botany, 2018).

Impact

Lonicera morrowii is a deciduous, woody shrub, native to Japan, China and the Republic of Korea. It was introduced to the USA from Japan in the 1860s as an ornamental, but has since escaped cultivation, is considered invasive and is prohibited in some states in the USA. It invades open woodlands, old fields and other disturbed sites, and spreads rapidly due to seed dispersal by birds and mammals. It can form a dense understory thicket which restricts native plant growth and tree seedling establishment. L. morrowii hybridizes with another non-native honeysuckle, L. tatarica, to produce L. x bella, and this plant is also considered invasive.


Source: cabi.org
Description


Planthoppers are insects that feed on plants by sucking sap from the plant tissues using their stylets (Backus, 1985). In general, leafhopper adults are often narrow and angular in appearance (Missouri Botanic Garden, 2016a).

Impact

Kallitaxila crini is a species of planthopper which has been introduced to Guam, the largest of the Mariana Islands in the Pacific Ocean, where it is a potential threat to an endangered tree species, Serianthes nelsonii. There is very little information about the distribution range and invasiveness of this species. It has been reported to be present on Honshu and the Bonin Islands of Japan and has been recorded as an invasive species in New Caledonia, however its specific impact does not appear to be documented.

Biological Control
<br>Introducing natural parasitoids and predators, and providing predators with alternative food sources for when planthopper populations are low, has been suggested as a way to control some planthoppers that are important agricultural pests (Weintraub and Wilson, 2010).

Source: cabi.org
Description


Adapted from Starr et al. (2003) and PIER (2013)

Impact

A. cordifolia is a succulent climbing plant native to South America that has proved to be very invasive in several countries where introduced, notably in Australia and on Pacific islands but also elsewhere. It smothers ground vegetation and, with its fleshy leaves and production of thick aerial tubers, it is so heavy that it easily breaks branches and can even bring down whole trees. It has shown itself to be a very damaging weed in moist forests, blanketing the ground and enveloping the canopy, restricting light and preventing the germination of native plants. A. cordifolia has been variously described as a ‘devastating weed’ that can ‘destroy a rainforest’. It has proved very difficult to control, but recent advances with biological control have shown potential following the release of the first agent in Australia in 2011.


Source: cabi.org
Description

S. cayennensis is a perennial evergreen herb or subshrub which can reach heights of 2.5 m. It has a woody glabrous stem with several branches. Leaves opposite, membranous, elliptic to broadly elliptic or ovate, 4-8 cm long, 2-4.5 cm wide, upper surface rugose, both surfaces glabrous or occasionally lower surface with a few scattered hairs usually along the veins and margins, margins sharply and coarsely serrate, the teeth conspicuously divergent, apex acute, base cuneate, petioles 0.5-2 cm long. Spikes slender, rachis flexuous to erect or somewhat nodding, 14-40 cm long, ca. 2.5 mm in diameter, the furrows somewhat shallow, nearly as wide as the rachis, bracts lanceolate, ca. 7 mm long;calyx ca. 7 mm long, the teeth subequal;corolla usually dark purplish blue with a paler center, the tube 7-8 mm long (Wagner et al., 1999).

Impact

S. cayennensis is a shrub native to South and Central America and the Caribbean. It was introduced widely introduced into several tropical countries around the world as an ornamental species due to its attractive blue flowers, but in some countries it has become invasive. S. cayennensis has a wide environmental tolerance and often invades disturbed areas where it can outcompete native flora. It is invasive in many Pacific islands and is regarded as a noxious weed in the Northern Territory, Australia and is increasing in abundance in Florida, USA. According to a risk assessment this species is regarded as being highly invasive (score 20 = high risk) (PIER, 2015).

Hosts

S. cayennensis may outcompete smaller native plant species and crops dedicated to livestock are often affected by smothering. In Australia, this species is commonly found as a weed of pastures and sugarcane (Saccharum species) (DAFF, 2014).

Biological Control
<br>No biological control agents have been released for S. cayennensis, however possible agents are discussed by Waterhouse and Norris (1987). The potential for biological control of the closely related species S. jamaicensis is discussed in detail by Cock et al. (1985).

Source: cabi.org
Description

C. debeauxii is an erect perennial herbaceous plant growing to 80 cm tall. Young plants have a strong tap root which may develop into a tough crown of several roots as plants mature. The basal rosette leaves are entire to deeply lobed and slightly hairy;stem leaves are small and without a stalk (sessile). Growth is openly branching, stems are slender and somewhat rough to the touch.

Impact

Centaurea debeauxii, a fertile hybrid of C. nigra and C. jacea, is an invasive perennial of pasture and natural grasslands with an increasing non-native distribution in wet temperate areas of continental North America, now also recorded in South America and Australia. Favouring mesic and moist situations, it can form dense stands, outcompeting native grasses and displacing broadleaved species. It is listed as a noxious weed in several western US states as well as one Canadian province. In natural and semi-natural plant communities, it threatens rarer endemics such as the rough popcorn flower (Plagiobothrys hirtus).


Source: cabi.org
Invasive species Cirsium mexicanum, Cirsium Long, Short
Description


Annual herbs, 10-40 dm tall;stems simple below, branching above, tomentose when young. Leaves usually lanceolate in outline, with deeply sinuate or lobed, spiny margins;lower surface whitish tomentose. Lower leaves up to 45 cm long and 18 cm wide, with long decurrent base, upper leaves to 10 cm long and 6 cm wide, truncate or lyrate. Inflorescence of terminal clusters of 3-5 or single heads on short peduncles arising from the axils of the upper and middle leaves. Heads with the involucre 8- or 9-seriate, 3-3.5 cm tall, 1.5-2 cm in diameter at the base, the outer involucral bracts 4-6 mm long, basally 1-2 mm wide, with a glutinous dorsal ridge, tapering to a 5-7 mm long spine, the innermost bracts 25-35 mm long, 1-2 mm wide, tapering, twisted and often purple near the tip;corolla purple to reddish, 26-30 mm long, the lobes 4-5 mm long, anthers colourless, 4-5 mm long, style purple 27-31 mm long. Achenes 4-5 mm long, 1-1.5 mm in diameter;pappus 23-25 mm long (Flora of Panama WFO, 2013).

Impact

C. mexicanum is a cosmopolitan herb included in the Global Compendium of Weeds (Randall, 2012). This species has been classified as invasive in Cuba (González-Torres et al., 2012) and Puerto Rico, and as an agricultural and environmental weed within its native distribution range which includes Mexico and Central America (Randall, 2012). This species is a fast-growing herb which spreads by seeds and produces a large number of bristled seeds which can be easily dispersed by wind (Pruski, 2013).

Hosts

C. mexicanum is listed as a weed which principally affects active pastures. In these areas, rosettes can grow forming dense monospecific stands. Previous studies have suggested that cattle do not feed on these plants (Cardenas and Coulston, 1967).


Source: cabi.org
Invasive species Lactuca floridana, Lactuca Long
Description


Annual or biennial herbs 0.3–1.5(–2.2) m tall, with a long slender taproot. Stems solitary, erect;branches ascending, glabrous. Basal rosette leaves triangular-ovate to oblanceolate, 80-370 mm long, 2.5-180 mm wide, lyrate pinnatifid, hairs only on veins, on petioles 20-40 mm long;bases attenuate to clasping;margins dentate;lateral lobes 1 to 3 pairs, triangular;terminal lobes not distinctly larger than lateral ones;apices rounded to acute. Cauline leaves alternate, large diminishing and less divided toward stem apex;bases clasping;apices acute. Synflorescences paniculate, 0.4-0.8 m long. Capitula terminal on 10-20 mm peduncles, each with 10–27 florets. Involucres cylindric, 8–14 mm long, 4-5 mm diam.;outer phyllaries 5-8 lanceolate 2-7 mm long, erect;inner phyllaries 6-9 linear 6-10 mm long. Florets all ligulate, 5-7 mm long, linear, bluish-white. Cypselae brown, subcylindric to compressed 4-6 mm long, speckled rugulose with 4-6 ribs;beaks 0.1-1 mm long. Pappus numerous barbellate bristles 4-5 mm long, white (description compiled from Strother 2006;Weakley et al. 2012;Puttock pers. obs.).

Impact

L. floridana is a weedy lettuce which can grow to almost 2 metres tall (Randall, 2012), locally common in disturbed areas within its native range and only found outside North America in Puerto Rico, where it is considered invasive. It is a fast-growing, annual or biennial herb of gardens, roadsides, waste ground and pastures, and is native to moist and wet woodlands in North America.


Source: cabi.org
Description


The following description is adapted from Flora of North America Editorial Committee (2015).

Impact

A. semibaccata is a low-growing shrub native to Australia. It is valued as a fodder plant and, along with many other Atriplex species, has been introduced around the world as a drought and salt tolerant forage. It was introduced to the USA where it has escaped cultivation and is now invasive in coastal grasslands, scrub and saline area, where it can form a dense cover inhibiting the growth of native plants. The California Invasive Plant Council classifies its potential impact on native ecosystems as moderate and control and eradication of this species appears possible. Many other Atriplex species are beginning to be reported as somewhat invasive in other parts of the world and the genus merits further attention in this regard.


Source: cabi.org
Invasive species Atriplex argentea, Atriplex Long
Description

A. argentea is an annual herb producing branching stems which can reach a height of 15-80 cm (Kadereit et al., 2010). Stems are decumbent to erect, densely branched, finely gray-scaly, peeling. The leaves are elliptic to deltate, grey-scaly, wavy-margined and usually triangular to roughly oval and 1-4 cm long. Staminate flowers emerge from June to September in small sessile axillary glomerules and terminal, interrupted spikes in distalmost bracteate leaves (Welsh et al., 1993). The inflorescences are rough clusters of tiny flowers, with male and female flowers in separate clusters. The inflorescence is pistillate with bracts in fruit 4–8 mm, fused to near top, widely deltate to round, generally tubercled, margins green, toothed. Seed 1.5–2 mm, brown with radicle either superior or lateral (Kadereit et al., 2010).

Impact

A. argentea is an annual herb, commonly known as silverscale saltbush. It is native to North America from southern Canada to northern Mexico, where it grows in many types of habitat (e.g. railroads and open, disturbed areas), generally on saline soils. It has been introduced to Argentina (Ferrando et al., 2003) and Denmark (in 1917;NOBANIS, 2015) but its distribution is scarce and it has not been characterized as invasive in these areas (NOBANIS, 2015). In California, USA, it has been reported, alongside other weedy species, as rendering habitat unsuitable for the endangered San Joaquin kit fox (Vulpes macrotis mutica) (US Fish and Wildlife Service, 2010). Many other Atriplex species are reported as invasive in different parts of the world and species of the genus merits further attention in this regard.


Source: cabi.org
Description

The following description is adapted from Miller (1988) and Flora of Panama (2018)

Impact

Heliotropium curassavicum is an aggressive weed that rapidly colonizes new areas, in particular on disturbed saline soils and coastal areas in arid and semiarid habitats. It forms dense monospecific stands that displace native vegetation and alter successional pathways. A combination of traits, such as high seed germination and seedling establishment rates in open areas, along with its ability to shift between sexual reproduction to clonal growth (i.e., adventitious root buds) are responsible for the invasiveness and rapid spread of H. curassavicum. H. curassavicum has become one of the most common weeds in the Mediterranean Basin and the Nile Delta, where it is regarded as a serious ecological and agricultural problem, but it is also listed as invasive in countries across Europe, the Arabian Peninsula, Africa and in Anguilla in the Lesser Antilles.


Source: cabi.org
Invasive species Ipomoea ochracea, Ipomoea Long
Description

I. ochracea is a slightly woody vine, twining, attaining 5 m in length, with scarce watery latex. Stems are cylindrical, slender, and pubescent. Leaves are alternate;blades simple, 3-10 × 2.5-7.5 cm, ovate, chartaceous, glabrous except for some hairs on the veins, the apex acuminate and usually mucronate, the margins entire or sinuate;upper and lower surface with the veins slightly prominent, the lower surface usually glaucous;petioles 2-6 cm long, pubescent. Flowers solitary or in double dichasia, axillary;peduncles slightly longer than the petioles;bracts ovate, approximately 1.6 mm long. Calyx green, not accrescent, of 5 subequal sepals, 5-7 mm long, chartaceous, ovate or oblong-ovate, glabrous, punctate;corolla pale yellow, with the base of the tube purple inside, infundibuliform, 3-4 cm long, the limb with 5 shallow, rounded lobes;stamens and stigmas white, not exserted. Capsule ovoid, glabrous, with a thin pericarp, 1.3-1.6 cm long, stramineous, with the sepals persistent, not accrescent at the base;4 seeds per fruit, 4-5 mm long, black, dull, glabrous (Acevedo-Rodríguez, 2005).

Impact

I. ochracea is a vine species included in the Global Compendium of Weeds (Randall, 2012). It is listed as invasive in Hawaii, New Caledonia, Puerto Rico and the Virgin Islands where it is also considered a weed mainly in ruderal and disturbed sites (Wagner et al., 1999;Acevedo and Strong, 2012;Randall, 2012). I. ochracea was introduced as an ornamental species from Africa into new habitats throughout the tropics. It has escaped from cultivation and has successfully colonized natural areas in coastal and riparian forests, thickets, grassland, river edges, river banks and disturbed sites (Goncalves, 1987;MacKee, 1994;Wagner et al., 1999).


Source: cabi.org
Description

Perennial aquatic or semi-aquatic herb. Stem highly variable, rooting in mud and freely branching or elongating in deeper water. Leaves alternate and whorled on same plant, pinnately divided, with submersed leaves having three to five pairs of divisions. Emersed leaves are 0.5-3 cm long, linear to lance-shaped, and have comb-like divisions or sharp teeth. Flowers either male or female, found on the same plant (monoecious), some bisexual, borne in a terminal spike above the water surface, with male flowers near the inflorescence tip. Bracts are longer than male flowers, triangular, with six to ten 1-2 mm long teeth that are angled toward the tip. Flowers green to purplish, small, four-parted, with 1.5-2 mm long petals that are rounded above and narrow-clawed. Fruit is a deeply four-lobed nut-like cluster, pale, 1.3-2 mm long, egg-shaped to cubic, splitting into four one-seeded segments that are flat-sided with two spiked ridges. Winter buds absent (Red de Herbarios del Noroeste de México, 2017).

Impact

Myriophyllum pinnatum is a perennial aquatic herb only reported as invasive in Cuba, where it is included in the management plan of the Ciénaga de Zapata Biosphere Reserve as a species that needs to be managed to prevent invasion of that wetland system. In some areas of its native range in North America, it is considered rare, endangered or extirpated due to habitat fragmentation and loss. In the USA, the species is considered endangered in Connecticut, Massachusetts, Indiana, New Jersey, New York, Rhode Island and Tennessee. M. pinnatum belongs to a genus recognized for the invasive species M. spicatum, M. aquaticum and M. heterophyllum.


Source: cabi.org
Description

H. coccineum is a vigorous perennial herb. Pseudostems grow up to 1.5-2 m height. Leaves sessile;ligule 1.2-2.5 cm;leaf blade narrowly linear, 25-50 × 3-5 cm, glabrous, base subrounded or attenuate, apex caudate-acuminate. Spikes cylindric, usually dense, glabrous or sparsely villous;bracts oblong, 3-3.5 cm, leathery, sparsely pubescent, rarely glabrous, 3-flowered, margin involute or rather flat, apex obtuse or acute. Flowers red. Calyx ca. 2.5 cm, sparsely pubescent especially at 3-toothed apex. Corolla tube slightly longer than calyx;lobes reflexed, linear, ca. 3 cm. Lateral staminodes lanceolate, ca. 2.3 cm. Labellum orbicular, ca. 2 cm wide or rather small, apex deeply 2-cleft. Filament ca. 5 cm;anther 7-8 mm. Ovary sericeous, 2.5-3 mm. Capsule globose, approximately 2 cm in diameter. Seeds red. (Flora of China Editorial Committee 2012).

Impact

Hedychium coccineum is an adaptable, tall, herbaceous, and very variable ornamental plant native to Asia. It can colonise natural or semi-natural habitats, from riverine fringe and mountain grasslands to forest understorey. In its introduced range, it can become dominant or co-dominant in natural or semi-natural environments, competing with and displacing indigenous species (e.g. in La Réunion, Africa;Brazil;South Africa). Similarly to other Hedychium species (i.e., Hedychium gardnerianum and H. coronarium), it is widely traded as a garden ornamental around the world. H. coccineum is included in the Global Invasive Species Database (2014) and the Global Compendium of Weeds (Randall, 2012) and is a declared weed and invasive species in some countries. Its environmental adaptability, high commercial appeal and growing impact in countries where it has established suggest its prospective spread in delicate ecosystems cannot be underestimated.

Hosts


Infestations of H. coccineum have been reported in plantations in South Africa as well as limited access to plantations caused by the plant (Henderson, 2001).

Biological Control
<br>None specifically for H. coccineum but a biocontrol initiative by CABI for a consortium of funders from New Zealand and Hawaii, USA, for Hedychium gardnerianum is ongoing and records/specimens of insects and diseases associated with all Hedychium congeners are being collected as part of the project (Djeddour D, CABI, personal observation, 2014).

Source: cabi.org
Title: Juncus tenuis
Description


The following is modified from PIER, 2016, after Wagner et al., 1999

Impact

Juncus tenuis, commonly known as slender rush, is a clump-forming, tufted perennial herb. In its native environment in the Americas, J. tenuis is not usually considered ‘weedy’ since it is relatively small and commonly grows as a plant of pathways and road verges. It is named as a minor weed of alfalfa in Oklahoma, USA. It has also been reported to sometimes invade urban lawns and to cause problems on golf courses in North America. It has been introduced to parts of Asia, Africa, Europe and Oceania, most probably unintentionally since seeds are sticky and readily attach to animals, clothes and car tyres. It is regarded as invasive in Hawaii (PIER, 2016). It has also been recently reported among invasive species in Croatian forestry (Horvat & Franjic, 2016).

Biological Control
<br>The species does not seem to be important enough as a weed to be considered as a target for biological control.

Source: cabi.org
Title: Juncus tenuis
Description

The following description is from Flora of Panama (2016)

Impact

S. linifolia is an herb or small shrub reported as invasive to Cuba and Hawaii, USA (Oviedo Prieto et al., 2012;PIER, 2016). No details are given on its invasiveness or the effects on habitats and/or biodiversity. Although it is listed as invasive for Hawaii by PIER (2016), it also is noted as “not common”.

Hosts

The species occurs as a weed in cultivated land and plantations (Fariñas et al., 2011;JIRCAS, 2016). It is one of the species affected by the Okra Mosaic Virus strain, NIN-OKMV, and could be a source of infection for some crops (Igwegbe, 1983).


Source: cabi.org
Invasive species Sida repens, Sida Portal
Title: Sida repens
Description

The following description is from the India Biodiversity Portal (2017)

Impact

Sida repens is a perennial herb native to Central America and parts of South America that grows as a weed in disturbed sites, wastelands, pastures and on roadsides. It has been classified as a weed in Cuba and as invasive in Puerto Rico and the Virgin Islands. This weedy species produces prickly fruits that attach to animal fur or human clothing, facilitating seed dispersal.


Source: cabi.org
Title: Sida repens
Invasive species Thunbergia fragrans, Thunbergia Long
Description

T. fragrans is an herbaceous vine, twining, 2-3 m in length. Stems cylindrical, striate, slender, puberulous. Leaves opposite;blades 6.5-11 × 1.8-6 cm, ovate to lanceolate, chartaceous, the apex acute, the base truncate or subcordiform;margins undulate and ciliate;upper surface dark green, glabrous or somewhat scabrous;lower surface pale green, dull, puberulous, with prominent venation;petiole 2-3.5 cm long, slender, pubescent, sulcate, with the base somewhat dilated. Flowers axillary, solitary or in pairs;pedicels pubescent, 5-7 cm long, striate;bracts green, membranaceous, ovate, pubescent, 1.6-2 cm long, covering the calyx. Calyx green, of 15-20 sepals, lanceolate, 3-5 mm long;corolla white, infundibuliform, with 5 lobes, the tube 2.5-4 cm long, narrow at the base, yellow inside, the limb 4-5 cm in diameter. Capsules 1-2.5 cm long, depressed-globose at the base, the upper half in the form of a beak, dehiscent in two halves;seeds 4, globose, approximately 5 mm in diameter, pubescent, with a depression at the base (Acevedo-Rodríguez, 2005). Variation in the shape, size, pubescence, and margin form of the leaves is extensive in T. fragrans, and taxa have been recognized based on these characters (Flora of China Editorial Committee, 2014).

Impact

T. fragrans is an herbaceous fast-growing vine widely cultivated as an ornamental in tropical and subtropical regions of the world, but it is also a common weed in moist disturbed areas, in particular along roadsides (Starr et al., 2003;Randall, 2012). In most cases, this species has been intentionally introduced as an ornamental and it has escaped from cultivation and naturalized in both relatively unaltered and disturbed forests, riversides, roadsides and urban bushland (Starr et al., 2003;Meyer and Lavergne, 2004;Queensland Department of Primary Industries and Fisheries, 2011). T. fragrans is included in the Global Compendium of Weeds where is listed as an “environmental weed,” and it is also listed as invasive in Australia, Japan, Singapore, Cuba, Puerto Rico, Hawaii and French Polynesia among others (Meyer and Lavergne, 2004;Mito and Uesugi, 2004;Chong et al., 2009;Queensland Department of Primary Industries and Fisheries, 2011;Oviedo-Prieto et al., 2012;PIER, 2014).


Source: cabi.org
Description


Perennial, woody vine, 10-20 m in length. Stems are cylindrical, up to 2.5 cm in diameter, striate, puberulous;cross section of the stem with the pith hollow and the xylem tissue with wide rays. Leaves are opposite;blades 15-26 × 13-30 cm, ovate or broadly ovate, chartaceous, the apex acute or acuminate, the base cordiform, the margins lobate-dentate, ciliate;upper surface is dark green, shiny, puberulous, with slightly prominent venation;lower surface is light green, dull, glabrous or puberulous, with prominent venation;petioles 6-12 cm long. Flowers are arranged in axillary cymes;pedicels robust, cylindrical, 4-6 cm long;bracts light green, ovate, approximately 4 cm long, covering the calyx and the corolla tube. The calyx is green with the form of a ring, 4-5 mm long;corolla lilac-blue or white, with 5 lobes, the tube 6-7 cm long, light yellow inside, narrow at the base, the limb 6-7 cm in diameter. Fruits are capsules, approximately 3 cm long, subglobose at the base, the upper half in the form of a beak, explosively dehiscent in two halves (Acevedo-Rodríguez, 2005).

Impact

T. grandiflora is a woody vine included in the Global Compendium of Weeds and it is listed as a very aggressive weed impacting tropical and subtropical ecosystems (Randall, 2012). This species has been repeatedly introduced as an ornamental plant in many countries around the world, but it has become a serious environmental problem when it has escaped from cultivated areas and rapidly colonized natural habitats (ISSG, 2012). The rapid colonization of new habitat by this vine is mainly due to its capability to reproduce sexually by seeds and vegetatively by cuttings, fragments of stems and roots (USDA-NRCS, 2012). Once established, T. grandiflora completely smothers native vegetation by killing host-trees, out-competing understory plants, and negatively affecting the germination and establishment of seedlings of native species (Starr et al., 2003). Currently, T. grandiflora is classified as a “noxious weed” in Australia (Queensland Department of Primary Industries and Fisheries, 2007), and as an invasive species in Central America, the West Indies, Africa, and numerous islands in the Pacific including Hawaii, Fiji, French Polynesia, Palau, and Samoa (see distribution table for details;Acevedo-Rodríguez and Strong, 2012;ISSG, 2012;PIER, 2012).


Source: cabi.org
Invasive species Verbena litoralis, Verbena Short
Description


Webb et al., (1988) describes V. litoralis as a

Impact

Verbena litoralis is a short-lived herbaceous plant, native to many of the tropical areas of Central and South America. Although the species has spread to other countries from its native environment, and is sometimes regarded as an invasive threat (in Australia and some states of the USA), it often seems to be restricted to disturbed habitats like roadsides, stream banks, tracks and waste places. Information on its effects on other plant species is not well reported, nor is there any evidence to suggest it has any serious impacts on specific environments or ecosystems.

Hosts


No mention found of any particular species affected by its presence.


Source: cabi.org
Invasive species Cornu
Description

C. sericea is a deciduous shrub with brightly coloured (often red) stems in the winter. The stems root along nodes, and spread by layering (EPPO, 2009b). The clones form large dense patches, with individual plants up to 3.7 m tall (USDA-NRCS, 2009) in both native and invasive habitats. The leaves are ovate to elliptic, green above, with 20-40 mm petioles (Karlsson, 2009). Long peduncles hold corymb-like infloresences of 20-50 flowers, each with 4 tiny white petals (1-3 mm). Fruit is a white to lead colour, subglobose pyrene (USDA, 1948) with a rounded base, wider than long (3.5 to 6 mm), with eight ridges (Karlsson, 2009).


Source: cabi.org
Invasive species Acanthaster planci Values
Description


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

Impact


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


Source: cabi.org
Invasive species Anoplolepis gracilipes
Description

A. gracilipes is one of the largest invasive ants, at around 4-5 mm long (Harris et al., 2005;Sarnat, 2008). The ant, also known as the long-legged ant, is notable for its remarkably long legs and antennae. The antennae have 11 segments and the antennal scape length is more than 1.5 times the head length, a key diagnostic feature (Sarnat, 2008;Csurhes, 2012). A. gracilipes workers are monomorphic, displaying no physical differentiation (Holway et al., 2002;AntWweb, 2013). It has a yellow-brownish or reddish brown body colour, and is weakly sclerotized. Workers have a long slender gracile body, with the gaster usually darker than the head and thorax. The eyes are large and bulge well beyond the outline of the head in full face view. The mesosoma is long and slender. The prontum in particular is extended anteriorly, giving the appearance of a long ‘neck’ (AntWeb, 2013).

Recognition


Ant identification can be done using morphological characters by a trained entomologist to species level. The Pacific Invasive Ant Key (PIAKey) and Pacific Invasive Ants Taxonomy Workshop Manual can both be used in identifying invasive ants in the Pacific region. A key diagnostic feature of A. gracilipes is the antennae, which have 11 segments and an antennal scape length more than 1.5 times the head length (Sarnat, 2008;Csurhes, 2012).
The detection method described below can be carried out in the field or in a port environment:
Bait station surveillance with high energy food source and visual inspection should be carried out to detect any suspected ants. Ant detection surveys should be conducted on sunny days between 20°C (18°C for cooler areas) and 36°C. Optimal temperatures are required to take advantage of the most favourable foraging conditions as an increase in temperature increases ant activity. Surveying is stopped if it rains or there is high wind.
Ensure survey/surveillance occurs within the defined ‘risk area’. A risk ais any place where an imported risk item (sea containers or imported timber, for example) has rested. Surveillance areas are defined as habitable ground within a 150 m radius of a risk site.
Visual Surveillance
Visual inspection should be carried out while conducting the bait station surveillance over the area and inspecting all trees and shrubs that are flowering or exhibit symptoms of sooty mould growth from eye height down. Where ants are found, collect specimens and place in labelled sample bottles. Mark each location where ants were found so that the locations can be found again.
Separate protein and sugar based baits should be composed and laid as follows:
Protein based bait: prepare protein based bait station (~60ml clear plastic container with a lid) by smearing in a line the blended peanut butter and soybean oil (the size of half a pea) to the inner side of each bait container on the side corresponding with the back of the label. In addition, a slice of processed sausage or smear of raw sausage meat is to be placed inside each pot.
Sugar based bait composition: prepare sugar based bait station by placing a plug of cotton wool soaked in 30% sugar solution inside the container, being sure to squeeze out the cotton ball to ensure ants can feed on the liquid without drowning. Alternatively, a smear of sugary jam may be used.
Each bait container (station) should be labelled with at least the date and the site name. Ants typically locate these baits with their natural foraging behaviour and will recruit additional worker ants to feed upon the bait.
Where the ant habitat is continuous, baits should be laid in rows 7-8 m apart, alternating between protein and sugar baits. Where the ant habitat is isolated, at least one of each bait type should be laid (minimum of one protein and one sugar bait stations within 15 square metres), ensuring they are at least 1 m apart. Ground locations of the bait stations should be marked with a crayon or spray paint spot during the course of surveillance. Bait stations should be collected approximately after two hours when temperature is between 20-24.9°C and after 30 minutes between 25-36°C after being laid. In the tropics bait stations should be placed in the shade where possible, as at temperatures above 28°C these baits are known to rapidly dry out, reducing their attractiveness to ants. Lids are put on the bait containers (station) to prevent ants escaping when they are collected. All bait stations should be sent to an entomologist to identify all samples in the bait station (as more than one species could be found in a bait station) and may require assistance from an expert to confirm the identifications (Sarty, 2007;Stringer et al., 2010;Gunawardana et al., 2013).

Impact

A. gracilipes, commonly known as the yellow crazy ant (so called because of its colour and frenetic movements), has invaded native ecosystems and caused environmental damage in numerous locations worldwide, including Hawaii (Gillespie and Reimer, 1993), the Seychelles (Haines et al., 1994) and Zanzibar (Wetterer, 2005). This species has been nominated by ISSG as one of the 100 ‘world’s worst’ invaders (ISSG, 2013).


Source: cabi.org
Description

T. minutum is an extremely small, inconspicuous, drab brown, soft-bodied ant in the subfamily Dolichoderinae (Hymenoptera: Formicidae). The following characters can be used to diagnose it from all known invasive and introduced ants. Total length ca. 1.5 mm. Head width ≤0.45 mm. Antenna 12-segmented. Antennal scape length less than 1.5x head length. Eyes medium to large (greater than 5 facets), do not break outline of head in full-face view. Antennal sockets and posterior clypeal margin separated by a distance less than the minimum width of antennal scape. Anterior margin of clypeus distinctly concave. Mandible with distinct break in tooth size after fourth tooth dorsum of mesosoma with metanotal groove, but never with a deep and broad concavity;lacking erect hairs. Propodeum with dorsal surface distinctly shorter than posterior face;lacking posteriorly projecting protrusion. Waist 1-segmented (may be hidden by gaster). Petiolar node appearing flattened. Gaster armed with ventral slit;with four plates on its dorsal surface and with the fifth plate on the ventral surface. Distinct constriction not visible between abdominal segments 3+4. Hairs not long, thick and produced in pairs. Uniformly light to dark brown, often with paler brownish yellow appendages.

Impact

T. minutum is a very small (1.5 mm), inconspicuous, drab brown, soft-bodied ant that occurs in Australia and Oceania. The species is widely considered native across this region, but it is possible that part of its current range resulted from anthropogenic dispersal. The species is most commonly found foraging and nesting in disturbed forest vegetation, but is also known to occur on the ground and in primary forest. Although little is known about the biology of T. minutum and it is not on any alert or pest lists, the species has been implicated in the decline of two endangered butterfly species endemic to Micronesia, primarily through the predation of eggs and larvae. T. minutum belongs to a taxonomically difficult species-complex that requires additional study before any of the known populations can be conclusively considered invasive. The species is rarely reported from quarantine interceptions and is unlikely to pose a significant invasion risk.


Source: cabi.org
Description

Solenopsis papuana are very small monomorphic ants. They have a light reddish yellow to medium reddish brown colouration. The total length of workers is around 1-2mm. Antennae are 10-segmented with a 2-segmented club. Eyes are small to medium in size and contain less than 10 ommatidia. The mandibles can have 4 or 5 teeth. The head is subquadrate, and is longer than it is wide. The metanotal groove of this species is distinct and the petiole is higher than the postpetiole. All the dorsal surfaces of S. papuana have erect setae. The gaster is oval with the first segment longer than half the total length (Harris et al. 2005).

Recognition


The Pacific Invasive Ant Key (PIAKey) manual Pacific Invasive Ants Taxonomy Workshop Manual can both be used in identifying invasive ants in the Pacific region.

Impact

Solenopsis papuana is a native ant of the Pacific region that thrives in the company of other more major invasive ants, but is not a major pest species on its own. It has been introduced to Hawaii and has been able to invade intact forest land.


Source: cabi.org
Description

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

Impact

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


Source: cabi.org
Invasive species Callisia fragrans, Wilts Long
Description


Wagner et al. (1999) describes the plant as a "perennial herb;stems fleshy, up to 1 m long, branched, with long stolons at base. Leaves clustered toward the ends of the stem, scattered below, elliptic-lanceolate, 18-25 cm long, 3.5-4 cm wide, base prominently veined, clasping, ciliate, often striped with purple. Flowers in compact pairs of cymes arranged in panicles up to 0.6 m long, each cyme pair subtended by 3-toothed bracts 10-15 mm long;sepals white-transparent, scarious, lanceolate, 5-6 mm long;petals glossy, white-transparent, thin, wilting by noon, narrowly ovate, erose, ca 6 mm long;stamens 6".

Impact

Callisia fragrans is a reasonably common cultivated, ornamental, perennial herb. It can be grown as a pot or basket plant or as ground cover in tropical or subtropical climates. In these warm climates, parts of the plant may break off or be spread by gardeners and start to grow. Occasionally considered invasive, it is established on Gros Piton, a World Heritage Site in Saint Lucia. In this habitat, its rapid spread is beginning to threaten native forest and displace many indigenous species.


Source: cabi.org
Invasive species Yellows
Description

Adult L. lutea are approximately 15 cm long, bill to tail, have olive-grey plumage on the crown, nape and back, with grey on the face around the eyes. The tail is black and deeply forked. The throat is a bright yellow transitioning to a darker yellow-orange towards the breast and the belly is dull yellow-grey. The bill is red and the base of the primaries is red. Otherwise the primaries are dark olive or black and the outer edges are bright yellow. Juveniles have duller wing patches and a black bill that may be redder towards the tip. Both sexes are very similar in appearance making them difficult to differentiate in the field. It has been suggested that the bright wing patches may be used for inter-specific communication in their dark habitats (Kawano et al., 2000).

Hosts

L. lutea changes habitats and has an effect on many native species (Woodward and Quinn, 2011). In the Hawaiian Islands, endemic bird species have become extinct partially due to avian malaria. As a known reservoir for this disease, L. lutea may have contributed to these extinctions (Global Invasive Species Database, 2008). L. lutea is being monitored on the Hawaiian Islands of Maui and Hawaii as a competitor and potential disease reservoir (U.S. Fish and Wildlife Service, 2006).


Source: cabi.org
Invasive species Yellows
Description

S. trilobata is perennial and grows to 45-60 cm high. Stems are green, rounded, rooting at nodes, 10-30 cm long, the flowering portions ascending, coarsely strigose to spreading hirsute, sometimes subglabrous. Leaves are medium textured, fleshy, usually 4-9 cm long (1.5-) 2-5 cm wide, simple obovate, irregularly toothed or serrate, usually with a pair of lateral lobes. The leaf arrangement is opposite to subopposite. Leaf venation is bowed and brochidodrome. Leaves are green in colour and do not change colour during autumn in the USA. S. trilobata usually flowers throughout the year. Flowers, solitary, arise in the leaf axils at any height but appear to have the most blossoms at about 10 cm above ground level. Peduncles 3-10 cm long, involucre, campanulate-hemispherical, 1 cm high;chaffy bracts lanceolate, rigid, ray florets often 8-13 per head, yellow in colour, rays 6-15 mm long;disk corolla 4-5 mm long;pappus a crown of short fimbriate scales (HEAR, 2008). Achenes tuberculate, 4-5 mm long with a brown, dry and hard fruit cover. Fruits are inconspicuous.

Hosts

S. trilobata is a threatening invasive species in agricultural and forestry land, urban areas and roadsides. It forms a dense ground cover, crowding or preventing regeneration of other species (HEAR, 2008). It has been reported as a weed of taro (Colocasia esculenta) in Fiji (Macanawai, 2013).


Source: cabi.org
Invasive species Butterfly, Yellows, Sterilizers
Description

A. calendula is a rosette-forming perennial usually infesting disturbed, urban, and coastal habitats. It prefers a good amount of sun and sandy, well-drained soil. It can grow up to 25 centimeters tall (10 inches) and exhibits purple or yellow daisy-like flowers that can reach 6 centimeters (2.5 inches) in diameter. The plant is pollinated primarily by butterflies. A sterile, vegetatively reproducing yellow-flowered race is not currently regulated in California, but is noted by some to escape from cultivation. This form is now considered a separate species, A. prostrata, sometimes sold in the nursery trade. The invasive A. calendula is regulated in California has purple-tinged disc flowers, is seed-producing, and listed as a category A weed.


Source: cabi.org
Invasive species Yellows
Description

Z. mauritiana is a small to medium-sized, single or multi-stemmed, spiny shrub or tree, which is almost evergreen, but is deciduous during the dry season. It has a round, spreading crown. It can reach up to 12 m tall and 30 cm diameter at breast height, but is highly variable in size and general appearance. Old protected trees of this species occasionally reach 24 m tall and 1.8 m diameter (von Carlowitz, 1991;Hocking, 1993). The bole is generally short, reaching 3 m in length at most. The bark is dark grey, dull black or reddish with long vertical fissures, reddish and fibrous inside (von Carlowitz, 1991). The branches are spreading and droop at the ends. The twigs are usually softly tomentose when young (Parker, 1956;Gupta, 1993). Z. mauritiana has a deep and lateral root system. Stipules are mostly spines, in pairs with one hooked and one straight, or both hooked, or rarely with neither as a spine. The leaves are simple, shining green above and whitish tomentose beneath, due to persistent dense hairs (occasionally glabrous), margins minutely serrulate, leaf shape ranging from almost round to an elongated ellipse, commonly sub-orbicular to ovate-oblong, rounded at both ends, highly variable in shape and size but always with three basal nerves and two stipular spines, one long and straight, the other small and curved back, and often brown in colour. Spineless types are not uncommon in this species (Singh, 1989). The leaves are solitary or in pairs, from 2 to 6 cm in length (occasionally 1.3-12.0 cm) and 1.5-5.9 cm at the widest point (occasionally 0.4-6.5 cm wide). Size variation is related to site quality and position on the tree, the leaves on vigorous new shoots being the largest (Parker, 1956;Hocking, 1993). Flowers are minute, greenish-white or yellow, hermaphrodite, in sessile or shortly peduncled axillary cymes, and are insect pollinated (Patel et al., 1988;Devi et al., 1989) with an acrid smell (Azam-Ali et al., 2006). The fruit is initially green and turns yellow, orange and red on ripening;being a drupe containing sour-sweet pulp and a hard stone. It varies in size from 1.2 to 3.7 cm long, and is generally globose or ovoid, and glossy. The fruits on wild plants reach about 2 cm in diameter, and on cultivated varieties can exceed 5 cm long. The stone in the fruit is irregularly furrowed and usually contains two cells and two seeds (Hocking, 1993), which have papery testa.

Hosts

Z. mauritiana is not generally a weed of agricultural land, as it is removed during cultivation;however, it is an invasive species in some rangeland and pastures, reducing the presence of other forage species. It is occasionally a weed of natural forests, as in Australia, where Z. mauritiana has been recorded invading eucalyptus woodland (Weber, 2003) and abandoned or fallow land (Morton, 1987).


Source: cabi.org
Description

Shrub or suffrutescent herb to 1.5 m tall, stem striate, strigulose. Leaves trifoliolate, the terminal leaflets narrowly elliptic to elliptic, the apex acute, acuminate or mucronulate, the base cuneate, 4.5-5.5 cm long, 1.1-1.5 cm broad, the margins entire, above glabrous, beneath sparsely strigulose, the veins 8-10 on each side of the mid-vein, the lateral leaflets similar, but slightly smaller;petiole 3-4 cm long, the stipules absent. Inflorescences terminal, lax racemes bearing up to 20 flowers;bracts linear triangular, 1-2 mm long, caducous;pedicels 5-6 mm long;bracteoles linear, 1 mm long, strigulose, located at the base of the calyx tube, caducous. Flowers yellow, 15-18 mm long;calyx 8-9 mm long, the tube truncate, the lobes about 1.5 times as long as the tube, strigulose;corolla yellow or tinged with violet, 15-18 mm long, the standard 13-14.5 mm long, 14.0-15.5 mm broad, retuse, the wings 13-14 mm long, the claws 2-3 mm long, oblong obovate, oblique, the keel 14-15 mm long, the non-twisted beak prolonged;stamens dimorphic, the long anthers 3.3-3.5 mm long, the short anthers 0.7-0.8 mm long;style with a pubescent stigma, curved geniculate, 9.5-12.0 mm long. Legume inflated, 2.5-3.1 cm long, strigulose;seeds approximately 20, brown, oblique, 3 mm long (Flora of Panama, 2015).

Impact

C. maypurensis is a shrub or herb listed as invasive in Cuba by Oviedo Prieto et al. (2012), although other databases regard it as native on this island (Acevedo-Rodríguez and Strong, 2012;USDA-ARS, 2015). Within its native distribution range in tropical America, this species is associated with disturbed vegetation and grows in open ground, secondary forests and riparian sites (Gómez-Sosa, 2000;Avendaño, 2011).


Source: cabi.org
Description


Leafy shrubs or small trees 1-5 (-6.5) m tall. Leaflets 3-4 (5) pairs, the distal ones larger, broadly ovate to lanceolate, (3.5-) 4.5-10.5 cm long, (1.1-) 1.4-3.5 cm wide, glabrous, lower surface pale, apex acuminate or caudate, base obliquely rounded or cuneate, petiolar nectaries between all pairs or all but the distal pair of leaflets, none contiguous to pulvinus, the lowest one 1-2 mm long, stipules submembranous, narrowly lanceolate, 3-7 mm long, caducous. Flowers in racemes (1.5-) 2.5-8 cm long, pedicels (12-) 15-25 mm long, bracts sub-membranous, linear, lanceolate, or subulate, (1.5-) 2-4.5 mm long, caducous as pedicels begin to elongate;calyx lobes yellowish green, yellowish brown, or completely yellow, the outer ones relatively firm, ovate-elliptic, 4-6.5 mm long, the inner ones submembranous, oblong-obovate or suborbicular, 6.5-10 mm long;petals bright yellow, the standard obovate to obovate-flabellate, deeply emarginate, the others obovate, the longest petal 12-16 mm long;staminodes 3, obovate or suborbicular, (1.7-) 2-2.6 mm long;filaments of 4 median stamens 1.3-2.2 mm long, those of 2 abaxial stamens dilated, ribbon-like, 7-10.5 mm long, that of abaxial central stamen 2-4 mm long. Pods ascending on a stiff pedicel, chartaceous, cylindrical or obtusely quadrangular, 6-10.5 cm long, 0.8-1.1 cm wide, cavity moderately pulpy, divided into 2 parallel rows of of cells. Seeds oriented with broad face to the septum, olive or brown, compressed-obovoid, 3.6-4.9 mm long, constricted at the hilum, smooth or minutely pitted, without an areole (Wagner et al., 2014).

Impact

S. septemtrionalis is a leafy shrub or small tree which abundantly produces seeds that are easily dispersed by humans (machinery and vehicles), birds and animals, and by water (West, 2003). Once established in new areas, this species matures quickly, negatively impacting native flora. The species is listed in the Global Compendium of Weeds as an “agricultural weed, cultivation escape, environmental weed, garden thug, naturalized, weed” with records of occurrences in North and Central America, South America, Asia, Asia-Pacific, Africa, Australia, and Europe (Randall, 2012;DAISIE, 2014;USDA-ARS, 2014). It is considered invasive in Fiji, Australia, Ecuador, Hawaii, New Zealand, and a weed in South Africa and the United States (see Distribution Table;Randall, 2012;PIER, 2014). It is also recorded as invasive in Burundi, Ethiopia, Kenya, Malawi, Rwanda, Tanzania and Uganda. The species was given an Australian rating of 4, indicating it is “naturalised and known to be a major problem at 3 or fewer locations within a State or Territory” (Groves et al., 2003);according to the Global Compendium of Weeds, the species is indeed invasive in some parts of the country (Randall, 2012).


Source: cabi.org
Description


Small trees, 3-6 m tall. Leaves 8-18 cm long, leaflets 6-10 pairs, the distal ones larger and proportionately narrower, obovate to elliptic obovate or oblanceolate, 2-5 cm long, 0.8-2 cm wide, upper surface green and usually glabrous, lower surface glaucous and sparsely appressed pubescent, especially along midrib, apex rounded, emarginate, base obliquely rounded or cuneate, clavate nectaries between the first, second, and sometimes third pairs of leaflets, stipules linear subulate, 4.5-13 mm long, caducous. Flowers in racemes 0.4-2.5 cm long, pedicels 15-25 mm long, bracts submembranous, ovate to lanceolate, 2-7 mm long, persistent until anthesis, then deciduous, the lowermost sometimes subtended by a clavate nectary;calyx lobes oblanceolate to oblong obovate, the outermost 3-4.4 mm long, inner ones 5.5-8 mm long;petals bright yellow or yellowish orange, ovate to oblong ovate, the longest one 16-24 mm long;fertile stamens 10, all nearly similar to one another, slightly increasing in size toward abaxial side of flower;filaments 9, 0.7-2 mm long, that of central abaxial stamen 1.5-3.5 mm long. Pods pendulous, chartaceous, strongly compressed, 7-10 cm long, 1.1-1.5 cm wide, base constricted into a stipe 0.5-0.7 cm long, the cavity with narrow interseminal septa. Seeds oriented transversely in 1 row, compressed parallel to the valves, pale brown, glossy, oblong ellipsoid, 5-6 mm long, the areole 2.7-3.6 mm long [taken from Wagner et al., 2014].

Impact

S. surattensis is a small tree which is listed as an ‘agricultural weed’, ‘environmental weed’, ‘cultivation escape’, ‘garden thug’, ‘naturalised’ and ‘weed’ in the Global Compendium of Weeds (Randall, 2012). It is known to shade out forages in mesic pastures and has a history of repeated introductions outside of its native range (Motooka et al., 2003;PIER, 2014). However the species has been spread primarily by human cultivation rather than by seed dispersal, as its pods lack pulp and its seeds are not well adapted for dispersal by biotic or abiotic factors (PIER, 2014). A risk assessment conducted by PIER (2014) called for further evaluation of the species’ invasiveness and risk of introduction. It is currently classified as an invasive species in several Asian and Pacific countries including Singapore, Taiwan, French Polynesia, and Micronesia, as well as Hawaii (PIER, 2014;Taiwan Invasive Species Database, 2014;USDA-ARS, 2014;Wagner et al., 2014).


Source: cabi.org
Description

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

Impact


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

Hosts


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


Source: cabi.org
Invasive species Senna spectabilis, Yellows Short, Long
Description


Tree to 10 or more metres high, the branchlets usually tomentose when young. Leaves moderately large, an average leaf about 20-foliolate;petiole short, pubescent, eglandular;rachis usually about 2 dm. long, eglandular and otherwise like the petiole;leaflets several to many pairs, lanceolate, 3-8 cm. long and usually about 2 cm. wide, acute apically, obtuse basally, pubescent below, especially along the veins, puberulent to subglabrous above and less dull than below, opposite on the rachis, with 10 or more pairs of prominent lateral veins;petiolules 2-3 mm. long, pubescent. Inflorescence of several terminal or subterminal several-flowered racemes;bracts lanceolate, a few mm. long, caducous. Flowers yellow;sepals 5, obovate-orbicular, markedly unequal, up to 1 cm. long and broad, glabrous to lightly puberulent;petals 5, mostly obovate, markedly unequal, up to 2.5 cm. long and 1.5 cm. broad, subglabrous, venose, short-clawed;stamens 10, 3-morphic;the 3 lowermost the largest, their anthers oblong, about 7 mm. long, short-rostrate apically and dehiscent by terminal pores, the loculi somewhat converging terminally;anthers of 4 median stamens 5-6 mm. long, similar to the 3 lowermost except the rostrum reflexed and the loculi divergent terminally;3 uppermost stamens markedly dissimilar, more or less rudimentary, the anthers distinctly bilobed, each lobe reniform and dehiscent the length of its outer margin;ovary linear, glabrous. Legume linear, turgid-quadrangular, up to 2 dm. long and 1 cm. wide, transversely multiseptate, tardily dehiscent along one margin (Missouri Botanical Garden, 2014).

Impact

S. spectabilis is a medium to large tree from tropical America, listed in the Global Compendium of Weeds as an ‘environmental weed’, ‘garden thug’, and ‘naturalised weed’ (Randall, 2012). The species is extremely fast-growing, flowers and sets seed profusely, and re-sprouts readily when cut (Mungatana and Ahimbisibwe, 2010). In Australia it is considered naturalized, has been recorded as a weed of the natural environment and an escape from cultivation, and is labelled an invasive species, indicating its high negative impact on the environment due to its ability to spread rapidly and often create monocultures (Randall, 2007). In Uganda, the species is considered an invasive alien species with high risk to the native flora (Mungatana and Ahimbisibwe, 2010). In Singapore S. spectabilis has been identified as a casual, spontaneous exotic species that survives outside cultivation but does not form self-replacing populations, and relies on repeated introductions or limited asexual reproduction for persistence (Chong et al., 2009). The species is a cultivation escape in Trinidad and Tobago (Irwin and Barneby, 1982) and is considered an invasive species in Cuba (Oviedo-Prieto et al., 2012).

Hosts


Agroforestry experiments in Kenya showed that while S. spectabilis is useful as hedges for cropping systems, if grown in semi-arid conditions S. spectabilis will out-compete crops for water uptake and suppress crop yields;in the cases recorded, grain yields of maize grown with S. spectabilis or Leucaena leucocephala were reduced by between 39% and 95% (Noordwijk et al., 2004).


Source: cabi.org
Description


Evergreen shrub 1.5-2.5 m tall;stems stellate-tomentulose, nearly cylindrical, becoming glabrous. Leaf blades 6-20 x 4-12 cm, ovate to nearly lanceolate, chartaceous, stellate-tomentulose, especially beneath, the apex acute, obtuse, or seldom rounded, the base obtuse to rounded, usually unequal, the margins entire;petioles 1.5-5.5 cm long, stout, stellate-tomentulose. Flowers in terminal (appearing as axillary) bifid cymes;pedicels stout, 3-5, 4-6 mm long, stellate-tomentulose. Calyx bell-shaped, ca. 5 mm long, stellate-tomentulose, the sepals triangular;corolla white, widely bell-shaped, ca. 5 mm long, deeply lobed, stellate-tomnetulose without, the tube greenish within, the lobes ovate, spreading to reflexed;anthers connivent, yellow, oblong, ca. 2.7 mm long;style exerted beyond the anthers, slender, the stigma nearly capitate. Berry leathery, globose, 1-1.2 cm long, sparsely to densely covered with minute, stellate hairs, turning from green to yellowish, with brown spots. Seeds numerous, reddish brown, lenticular, ca. 1.7 mm long. [Acevedo-Rodriguez, 1996].

Impact

S. erianthum is a shrub listed as ‘cultivation escape’, ‘environmental weed’, ‘naturalised’ and ‘weed’ in the Global Compendium of Weeds (Randall, 2012). The species reproduces both by seeds, which are numerous (Acevedo-Rodriguez, 1996), and by adventitious roots which form colonies (Roe, 1979). It is known to be an invasive cultivation escape in Queensland, Australia and is naturalized in parts of the tropics including New South Wales and Northern Territory, Australia (Randall, 2007;2012). Other places where the species is a known weed include Puerto Rico (Liogier and Martorell, 2000;Randall, 2012), West Africa (Jaeger and Hepper, 1986), New Guinea (Symon, 1986), China and Taiwan (Randall, 2012).


Source: cabi.org
Invasive species Cylindropuntia rosea, Yellows Long
Description

C. rosea is a succulent shrub branching basally with ascending spiny stems. It grows up to 1 m tall, although some plants have been reported to reach up to 1.5 m high in Australia (Hosking et al., 2007) and forming clumps up to 3 m wide. It has cylindrical stem segments, grey to green, 10-15 cm long and 1.6-2.5 cm in diameter, with distinct tubercles. It presents large areoles (2-3.5 cm) and yellow glochids 2-5 mm long. Its flowers are rose coloured (4-5 cm long), and its fruits are obconical to obovoid, yellow, spiny and with distinct tubercles. See Anderson (2001) for more information.

Recognition

Cylindropuntia species (all of them potential invaders) are easily identified by their spiny cylindrical stem segments. Walters et al. (2011) provide a useful identification key to distinguish C. rosea (referring to it as C. pallida) from other common Cylindropuntia invaders.

Impact

C. rosea is a densely spiny cactus native to Mexico. It is known to be cultivated as an ornamental plant in Australia, South Africa and Spain and it is also used as a barrier plant in Namibia and Botswana. C. rosea is recorded as naturalized in Peru and invasive in Australia, France, Namibia, South Africa, Spain and Zimbabwe. Where it has become invasive, its thorns can cause severe injuries and even death to wild and domestic animals. In Australia, koalas, kangaroos and birds have being found dead due to the spines of C. rosea. Moreover, it causes negative impacts on native vegetation and agriculture. Efforts to improve biological control led to the discovery that it had been misidentified in South Africa and is instead the chainfruit cholla (Cylindropuntia fulgida) (Henderson and Zimmerman, 2003). In Queensland, it is a Class 1 declared pest plant and a restricted invasive plant under the Biosecurity Act 2014.


Source: cabi.org
Invasive species Barleria lupulina, Yellows Short, Long
Description

B. lupulina is a glabrous, erect and branched shrub, up to 1.5 m tall, with axillary spines;leaves linear-oblong, 3-9.5 cm long, base cuneate, apex obtuse, midrib red above, petiole short, red. Inflorescence a terminal spike with overlapping bracts, up to 9 cm long, bracts broadly ovate, 1.2 cm long, ciliolate, purple tinged, on the back with cupular glands, bracteoles lanceolate, 4 mm long;calyx lobes broadly ovate, pubescent, outer 10 mm long, inner ca 8 mm long;corolla tube 3 cm long, bent at base, expanded above, lobes 5, orange-yellow, stamens 4, didynamous, 2 exserted;longer stamen filaments approximately 2 cm long;shorter stamens fertile. Style approximately 3 cm long, glabrous. Fruit a capsule, ovoid, 2-seeded (Aguilar, 2001;PIER, 2015).

Impact

B. lupulina is a fast growing perennial plant widely commercialized as an ornamental. It has repeatedly escaped from cultivation and has become naturalized in disturbed sites and secondary forests (Aguilar, 2001;Smith, 2002;PIER, 2015). B. lupulina has a great spreading capability. Seeds are dispersed short distances when capsules rupture and by water and stem fragments and stolons can be dispersed accidentally in garden waste disposal. This species has become invasive in secondary dry forests, open woodlands, and along watercourses in Australia, Hawaii, Réunion, and East Timor (Weeds of Australia, 2015;PIER, 2015). It can form thorny thickets which are difficult to walk through, replace native species, and can block access to waterways and impede stock movements.


Source: cabi.org
Description

D. unguis-cati is a woody vine with tendrils, 10-15 m length. Stems are cylindrical, lenticellate, up to 6 cm in diameter;cross section of the mature stem with multilobed xylem, the lobes alternating with radially arranged phloem tissue;nodes thickened;interpetiolar zone not glandular. Pseudostipules are ovate, approximately 5 mm long. Leaves are opposite, 2-foliolate, with a terminal tendril, trifid like a claw, generally of short duration;leaflets 6-16 x 1.2-7 cm, elliptical, oblong or obovate, chartaceous or coriaceous, glabrous or with punctiform scales, the apex acute or acuminate, the base acute, rounded, or unequal, the margins undulate or rarely denticulate;upper surface dark, shiny, with sunken venation;lower surface light green, dull, with prominent venation;petioles 1-4.5 cm long, petiolules 0.5-2.5 cm long, both glabrous. Flowers are solitary or in pairs, axillary;pedicel 2 cm long. Calyx is green, campanulate, 12-16 mm long, with five unequal lobes;corolla brilliant yellow, infundibuliform, 4-8 cm long, the limb 3-6 cm in diameter, with five unequal lobes, rounded;4 stamens, didynamous, inserted;ovary covered with punctiform scales. Capsule is linear, somewhat woody, brown, 25-95 cm long;seeds numerous, 1-3.5 cm long, with two membranaceous wings (Acevedo-Rodríguez, 2005).

Impact

Dolichandra unguis-cati is a vigorous, woody vine that can climb up to 15 m or higher. Due to its showy yellow flowers, it has been widely introduced as a garden ornamental. It has escaped from cultivation and become a significant invader of cultivated orchards, riparian corridors, natural forest remnants and disturbed areas, such as roadsides and urban spaces. D. unguis-cati clings tenaciously to any substrate with adventitious roots and clawed tendrils. This vigorous growth allows it to sprawl over other vegetation and, through a combination of both shading and weight, it can kill even large canopy trees. In the absence of climbing support, D. unguis-cati grows along the ground forming a thick carpet that inhibits the growth and seed germination of native understorey vegetation including native grasses, herbs and seedlings of shrubs and trees. Currently, this vine species is listed as invasive in Kenya, Malawi, Tanzania,South Africa, Australia, New Zealand, India, China, Mauritius, New Caledonia, Cuba, the Bahamas and the USA including Hawaii, Florida and Texas (Kairo et al., 2003;Henderson, 2001;Weber et al., 2008;Weeds of Australia, 2011;Oviedo Prieto et al., 2012;Randall, 2012;PIER, 2016).

Biological Control
Biological control programmes were initiated in 1996 in South Africa and in 2001 in Australia (Shortus and Dhileepan, 2011). Biological control against D. unguis-cati has resulted in the release of two lace bugs, Carvalhotingis visenda and C. hollandi (Hemiptera: Tingidae), a leaf-mining beetle Hedwigiella jureceki (Coleoptera: Buprestidae), a leaf-tying moth Hypocosmia pyrochroma (Lepidoptera: Pyralidae), a seed-feeding weevil Apteromechus notatus (Coleoptera: Curculionidae) and Charidotis auroguttata (Coleoptera: Chrysomelidae: Cassidinae). With the exception of A. notatus, all agents were approved for release and exhibited promising rates of establishment and damage at a number of field localities (King et al., 2011).<br>

Source: cabi.org
Description

B. pertusa is a stoloniferous perennial. Stolons often pink, rooting at the nodes, creeping extensively to form a sward. Nodes bearded. Stems geniculately erect 60-100 cm high. Leaves up 10-30 cm long, 2-5 mm wide, apex acute, mainly crowded at the base of the culms, usually glabrous, but with some scattered hairs. Ligule cilate 1-2 mm long. Inflorescence sub-digitate with up to 12 shortly pedunculate purplish racemes each up to 7 cm long, the lowest longer than the central axis, pilose. Sessile spikelet narrowly elliptic 3-4 mm log, lower glume cartilaginous, hairy on the lower half, with one or two pits in upper half;fertile lemma reduced to a slender geniculate awn up to 20 mm (normally 10-17 mm) long. Pedicelled spikelet on densely hairy pedicel up to 3 mm long, glabrous, occasionally pitted, usually sterile. Caryopsis 1.5 to 2 mm long, and shed firmly enclosed in the fertile lemma with sterile lemma and awn still attached.

Impact

B. pertusa is a perennial grass native to eastern and southern Asia. It has been widely introduced outside Asia, in the Americas, Australia and the Pacific, either accidentally or probably in some cases deliberately for use as a forage grass. It has established itself in many habitats where it is able to out-compete native species due to its ability to establish dense mats and shade out slower establishing species. In Australia it is now an established invasive species in both the Northern Territory and central Queensland. It is similarly regarded as invasive in Mexico, in Cuba, Puerto Rico, the Dominican Republic, Anguilla and the Cayman Islands in the Caribbean, in Mauritius, and in New Caledonia, the Marquesas Islands, Midway Atoll and Hawaii in the Pacific. In Hawaii, it is among species threatening the endangered plants Spermolepis hawaiiensis and Wilkesia hobdyi. Through its effects on native vegetation, it likewise threatens the endangered lizard Ameiva polops in the US Virgin Islands, and affects populations of ants and birds in Australia.

Hosts

B. pertusa is rarely recorded as a weed of crops but may impact wild species as noted under ‘Impact on Biodiversity’.

Biological Control
<br>There is no record of any attempt at biological control.

Source: cabi.org
Description

A. nigrofasciata is a fairly small cichlid that grows to approximately 12 cm but more commonly to 8.5 cm in length (Page and Burr, 1991;Froese and Pauly, 2014). It is pale blue/grey in colour with approximately seven black vertical stripes/bars on the sides that extend onto the dorsal and anal fins. The vertical stripes vary in intensity and the first and third bar may appear as blotches. The first or second bar may be Y shaped. There is a black spot on the operculum. The fins are clear or light blue/grey. Large males may have intense black bars with long fin rays at rear of dorsal and anal fins (Page and Burr, 1991). Selective breeding has produced several colour variations including pink, albino, long-finned and marbled (Page and Burr, 1991).

Impact

A. nigrofasciata is a small, popular ornamental freshwater fish that is native to a number of countries in Central America. It occurs as an introduced species in the aquatic habitats of at least 10 countries, principally because of human-mediated translocation and release. Due to the popular ornamental status of A. nigrofasciata, it is rarely considered a “pest” species. Wide environmental tolerances, the ability to colonise disturbed habitats, trophic opportunism, parental care and fast growth rates all contribute to the likelihood of this species becoming invasive. Potential ecological impacts upon endemic fish fauna may include resource competition and predation of aquatic invertebrate communities as a whole. Research has suggested that A. nigrofasciata may be responsible for the displacement of native fishes in Mexico and Hawaii. Of particular note is that the species is aggressive, particularly when breeding as territories are established on the substrate and defended against all intruders.


Source: cabi.org
Description

A. ocellatus has an oval-shaped, laterally compressed body with a blunt head and large mouth with protrusible jaws. There are 7 pre-opercular pores and the eyes are large with orange/red iris.
The colour varies among natural populations with adults typically dark olive-green to grey to chocolate brown with scattered red-orange irregular spots along flanks, dorsal fin base and opercle margin. There is often a large black spot surrounded by an orange margin the caudal peduncle.
Juveniles are striped with white and orange wavy bands and white spots on the head.
Various ornamental colour varieties have been produced by selective including copper/red and black mottled patterns and also albino forms. Long-finned varieties have also been produced.
A. ocellatus grows to 35-45 cm TL, though usually to 20-28 cm TL. There is no sexual dimorphism.
It has a dorsal fin with 12-14 spines and 19-21 soft rays;anal fin with 3 spines and 15-17 soft rays. It also has dorsal and anal fins with densely scaled bases. The first gill arch is without a lobe;gill rakers short and thick with many denticles;dorsal and anal fins bases densely scaled;many branched rays. There are 31-36 scales on the lateral line and 34-37 scales in the lateral series (Page and Burr, 1991;Froese and Pauly, 2007).

Impact

Astronotus ocellatus, commonly known as the oscar, is a large, predatory cichlid that is very popular worldwide as an ornamental freshwater fish. It has been introduced to the aquatic habitats of at least 10 countries, principally because of human-mediated translocation and release. Due to the popular ornamental status of A. ocellatus, it is rarely considered a pest species. A. ocellatus has proven invasive because of wide environmental tolerances, the ability to colonise disturbed habitats, trophic opportunism and fast growth rates. Potential ecological impacts may include resource competition with endemic fish fauna and predation of aquatic invertebrate communities as a whole. Of particular note is the capacity of the species to consume small and moderate sized sympatric fishes due to its large size (up to 450 mm). Research conducted in North and South America has suggested that A. ocellatus may impact negatively on native fish fauna inhabiting similar ecological niches (see Impact section).


Source: cabi.org
Invasive species Alternanthera halimifolia Long
Description

Procumbent or decumbent sericeous perennials, the sparingly branched stems to 20 cm long. Leaves densely pubescent with stellate hairs, rarely glabrate, elliptic to ovate, apically rounded and mucronate, basally rounded to cuneate, 1-5 cm long, 0.5-2.5 cm broad;petioles 2-10 mm long. Inflorescences of stramineous ovoid heads, 4-12 mm long, 3-5 mm broad, sessile in the axils. Flowers perfect;bracts and bracteoles subequal, ovate, acuminate to aristate, 1-3 mm long;sepals 5, the outer 3 broader, 3-ribbed, basally indurate and hispidulous, 3-5 mm long;stamens 5, united below into a tube, the pseudo-staminodia lacerate and exceeding the filaments;ovary globose to obovoid;style 1, about twice as long as the capitate stigma. Fruit an indehiscent globose utricle 1-1.5 mm long;seeds reddish brown, cochleate-orbicular, 0.8-1.1 mm broad (Correa et al., 2004).

Impact

Alternanthera halimifolia is a pioneer species typically growing in disturbed and coastal areas. Its native range encompasses the majority of the Caribbean in addition to Central and South America. This species has been listed as introduced and invasive in Cuba, although some authors regard it as native to this island. It has also been listed as introduced in Puerto Rico and the United States Virgin Islands (St Croix and St Thomas). In Chile it has been previously listed as introduced but most recently included within a list of native flora. It behaves as a weed in ruderal sites, sea beaches, coastal sites, and thickets in areas both within and outside its native distribution range.


Source: cabi.org
Invasive species Chenopodium capitatum Short, Long
Description

C. capitatum is an annual or short-lived perennial (Sukhorukov et al., 2018). The following description is based on the one given in the Flora of North America (e Floras, 2008). Herbaceous, glabrous stems, 150–100 cm long, erect to ascending or decumbent, branching from the base. Leaves: blades lanceolate, ovate, triangular or triangular-hastate, 2.5–10 x 1–9 cm, base cuneate, truncate, or hastate, margins sharply dentate or entire, apex acute to acuminate;petiole 1.5–10 cm. Inflorescences: glomerules (dense clusters of small sessile flowers) borne on unbranched terminal spikes;spikes 5–20 cm;glomerules globose, 3–10 mm diameter;bracts leaf-like, present only at base of inflorescence;flowers maturing from apex to base. Flowers: perianth segments three, joined only at base, lobes lanceolate to ovate, 0.6–0.9 x 0.4–0.5 mm, apex acute, not keeled, glabrous, covering fruit at maturity, becoming fleshy and red in fruit;stamens three;stigmas 2, 0.1–0.4 mm. Achenes ovoid, may or may not be fleshy;pericarp adherent, bright red to dark reddish brown or greenish red, smooth. Seeds 0.7–1.2 mm in diameter, margins rounded;seed coat black, reticulate-punctate.

Impact

Chenopodium capitatum is a chenopod herbaceous plant found across parts of North America (where it is native), and also in Europe and New Zealand. It is sometimes cultivated as a horticultural crop;it has the potential to become an invasive species in some areas.


Source: cabi.org
Description

The following description is from PROTA (2016)

Impact

D. fuscescens is an annual, to perennial grass that is a weed of cultivated crops and disturbed soils (Useful Tropical Plants, 2016). It is also a weed of turf grass (Uddin et al., 2012). The species is listed as invasive in Asia (Chagos Archipelago), South America (Colombia, Peru) and Oceania (Fiji, French Polynesia, USA-Hawaii) (PIER, 2016).

Hosts

The species is reported as a weed of crops, including rice fields in Indonesia and Laos (Kosaka et al., 2006;PIER, 2016;PROTA, 2016).


Source: cabi.org
Description

E. atrovirens is a caespitose perennial grass. Rhizomes absent. Culms loosely tufted, erect or geniculate at base, 15–100 cm tall, approximately 4 mm in diameter, 4–8-noded. Leaf sheaths glabrous but pilose along summit;ligules a ciliolate membrane, 0.2–0.3 mm;leaf blades flat or involute, 4–17 × 0.2–0.4 cm, adaxial surface scabrous, near base pilose, abaxial surface glabrous. Panicle open, 5–20(–25) × 2–15 cm;branches one to several per node. Spikelets plumbeous and purplish, narrowly oblong, 5–15(–25) × 1.5–2.5 mm, 8–40-flowered, pedicels 0.5–5(–15) mm;rachilla persistent. Glumes 1-veined, 1–2.3 mm;lower glume ovate, 1–1.3 mm, apex acute, upper glume narrowly ovate, 1.3–2.3 mm, apex acuminate. Lemmas broad ovate, 1.8–2.2 mm, apex acute, lower lemma 2–2.2 mm, deciduous with palea. Palea loosely ciliate along keel, 1.6–1.8 mm. Stamens 3;anthers 0.7–0.9 mm. Caryopsis approximately 1 mm (Barkworth et al., 2004;Flora of China Editorial Committee, 2016).

Impact

Eragrostis atrovirens is a C 4 grass cultivated for pasture and hay in tropical and subtropical regions (USDA-ARS, 2016). It has escaped from cultivation and once naturalized it behaves as a weed in roadsides, disturbed sites, waste areas, riparian areas, and grasslands (Barkworth et al., 2004;Flora of China Editorial Committee, 2016;PIER, 2016;PROTA, 2016). This perennial grass has the capability to tolerate drought and high saline conditions as well as seasonally waterlogged conditions. Thus, it can be found growing in floodplain grassland and swampy grassland (Flora of Pakistan, 2016). Currently, it is listed as invasive in Australia, Micronesia, Palau, Chagos Islands, Cuba, and Mexico (Villaseñor and Espinosa-Garcia, 2004;Oviedo Prieto et al., 2012;Simon and Alonso, 2016;PIER, 2016).


Source: cabi.org
Invasive species Eragrostis lehmanniana Long
Description

E. lehmanniana is a perennial grass, without rhizomes but sometimes with stolons;culms up to 90 cm tall, erect, ascending or decumbent and rooting at the nodes, branched, glabrous at the nodes (but the internodes glabrous or pilose), eglandular;basal leaf sheaths shortly pilose below or sometimes glabrous, chartaceous, ± compressed and keeled, eglandular, persistent;ligule a line of hairs;leaf laminas 6-25 cm x 1.5-3.5 mm, linear to broadly linear, flat to involute, puberulous above, eglandular. Panicle (7-)9-16(-18) cm long, ovate to narrowly ovate-elliptic, loose and open, the spikelets condensed about the branchlets on pedicels 0.5-1 mm long, the primary branches not in whorls, terminating in a fertile spikelet, glabrous in the axils, eglandular. Spikelets 4-11(-12) x 1-1.5 mm, oblong to linear, lightly laterally compressed, (4-)7-15-flowered, the lemmas disarticulating from below upwards, the rachilla persistent below, sometimes becoming fragile above;glumes 1.3-2.0 mm long, subequal, 1-veined, reaching to between half and two-thirds (even three-quarters) of the way along the adjacent lemmas, lightly keeled, narrowly oblong-lanceolate in profile, smooth or scaberulous on the keel, subacute at the apex;lemmas 1.8-2 mm long, 3-veined, lightly keeled, elliptic-oblong in profile, membranous with distinct lateral nerves, appressed to the rachilla, those in opposite rows scarcely overlapping, the rachilla ± visible between them, dark green, grey-green or reddish, faintly asperulous on the back, obtuse to acute, shallowly 3-lobed at the apex;palea persistent or rarely deciduous with the lemma, glabrous on the flanks, the keels slender, wingless, smooth or scaberulous;stamens 3, anthers 0.7-1 mm long. Caryopsis 0.6-0.8 mm long, oblong to elliptic (PROTA, 2015).

Impact

Eragrostis lehmanniana is a grass native to southern Africa and introduced to arid areas of India, the USA, Brazil, Argentina and Venezuela. It has become invasive, especially in the southwestern USA (primarily in Arizona), where it was introduced in the 1930s for range restoration purposes. E. lehmanniana is also used as a forage grass, despite only the immature plants being palatable. It reproduces primarily by seeds, which are easily spread by wind, water, animals and vehicles. E. lehmanniana impacts ecosystems by altering fire regimes and displacing indigenous species.

Biological Control
<br>No classical biological control agent is available for this species (USDA Forest Service, 2014).

Source: cabi.org
Invasive species Eragrostis plana Long
Description

Densely caespitose perennial without rhizomes or stolons;culms up to 90 (100) cm tall, strongly compressed below, erect, unbranched, glabrous at the nodes, eglandular;basal leaf sheaths glabrous, chartaceous, strongly compressed, keeled and usually flabellate, eglandular, persistent;ligule a line of hairs;leaf laminas 10-80 cm x 1.5-4 mm, linear, flat or folded, glabrous, eglandular or with punctate glands along the midnerve. Panicle 10-35 cm long, narrowly oblong to narrowly ovate, the branches ascending or spreading, the spikelets appressed to the branchlets on pedicels 1.5-2 mm long, the primary branches not in whorls (but sometimes loosely clustered), terminating in a fertile spikelet, glabrous or thinly pilose in the axils, eglandular. Spikelets 6-13.5 x 0.5-2 mm, linear to narrowly oblong, laterally compressed, 9-13-flowered, the lemmas disarticulating from below upwards, the rhachilla persistent;glumes unequal, keeled, oblong-lanceolate in profile, scaberulous on the keel, acute at the apex, the inferior 0.5-0.8 mm long, reaching to about 1/3 the way along the adjacent lemma, the superior 0.9-1.5 mm long, shorter than the adjacent rhachilla internode or just exceeding the base of the adjacent lemma;lemmas 1.8-2.5 mm long, keeled, semi-ovate in profile (with straight or rarely concave keel and gibbous margins), membranous with prominent lateral nerves, appressed to the rhachilla, those in opposite rows not overlapping, the rhachilla visible between them, olive-green, glabrous but with punctate glands on the nerves, subacute at the apex;palea persistent, glabrous on the flanks, the keels slender, wingless and glabrous to scaberulous or slightly thickened with punctate glands;3 anthers, (0.9)1.6-2 mm long. Caryopsis (0.8)0.9-1.2 mm long, oblong to elliptic (Cope, 1999).

Impact

Eragrostis plana is a perennial grass native to southern African savannas. It is invasive in grassland ecosystems in southern Brazil, Uruguay and Argentina. In Rio Grande do Sul, Brazil, where it was accidentally introduced as a seed contaminant in the 1950s, it was then planted across the area as a forage alternative, but has since outcompeted native species in pastures and in native grasslands. The species is currently established on more than two million hectares of grasslands in southern Brazil. There, it flowers every three weeks in the warm months, tolerates frost and resprouts if mowed or grazed. E. plana thrives over compacted soil, being common on roadsides and parking lots, as well as in overgrazed areas. Seeds remain viable in the soil more than 24 years. It has proven a poor forage species and its invasion has resulted in economic losses to cattle ranchers.

Biological Control
No studies on biological control for this species are available, but Coelho (1993) recommends exploring this approach due to the difficulty of controlling the species chemically or mechanically.

Source: cabi.org
Invasive species Euphorbia lactea Developed, Long
Description

A cactus-like, usually leafless but evergreen shrub or small tree up to 5 metres high and 15-20 cm in trunk diameter, with fleshy or succulent stems, much branched, hairless throughout, producing abundant milky sap when injured. Stems with whorls of branches nearly to base but on large plants shedding the spiny tissue and developing a rounded brown, fissured trunk. The 3-angled (sometimes 4-angled) branches are mostly joints 10-30 cm long and 2-5 cm across, slightly shiny dark green, with yellowish or whitish streak in the groove of the axis between the angles. The soft cut branches have a light green outer layer less than 0.5 cm thick, which yields latex, and within whitish watery tissue, slightly bitter. Raised leaf bases 0.5 cm high and about 1-2.5 cm apart along the edges of branches correspond to nodes and bear paired spreading gray spines (stipules). Leaves few, scattered, alternate, minute, stalkless, rounded, slightly shiny green, succulent, slightly thick and shedding early, or absent. Flowers small, yellowish green, borne intermittently in small clusters along the stem’s edge (Little et al., 1974).

Impact

E. lactea has been widely commercialized as an ornamental plant and due to the presence of spines it is also used as a fence/hedge plant. Many cultivars have been developed for the horticultural trade (USDA-ARS, 2016). It has escaped from cultivation and once naturalized, it often grows forming thickets mostly in disturbed sites, abandoned gardens, deciduous forests, coastal forests, and along roadsides (Little et al., 1974;PIER, 2016;PROTA, 2016). E. lactea spreads by seeds and vegetatively by cuttings and stem fragments (Little et al., 1974). Currently, this species is listed as invasive in Hawaii and Cuba (Oviedo Prieto et al., 2012;PIER, 2016). In Puerto Rico and the Virgin Islands, it is spreading and forming thickets in some places (Little et al., 1974).


Source: cabi.org
Description

The following description is from the Flora of China Editorial Committee (2016)

Impact

Euphorbia tithymaloides is a succulent, perennial shrub widely cultivated as an ornamental plant. Native to the Americas, this species has been introduced in Africa, Asia and Oceania, occurring on rocky soils in dry, sunny habitats such as hillsides, wastelands and roadsides. Currently it is listed as invasive in New Caledonia, Wake Island, the British Indian Ocean Territory and Cuba. Despite being classified as high risk in the Hawaii-Pacific Weed Risk Assessment, its environmental impact on native species and habitats is unknown.


Source: cabi.org
Description

The following description is from Burger and Huft (1995)

Impact

Euphorbia umbellata is a succulent shrub, widely cultivated as an ornamental. It grows in dry open woodland, rocky areas and also in disturbed habitats, where it has escaped from cultivation. Currently it is listed as invasive in India and Cuba, although there is no information available about its environmental impacts in either country. In Australia, it is listed as a minor environmental weed.


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


Description of P. ligularis adapted from Morton (1987), Holm-Nielsen et al. (1988), Davidse et al. (1994), Wagner et al. (1999), Mendes Ferrão (2002), Rodriguez (2007), Hyde et al. (2016) and Duarte and Paull (2015).

Recognition

P. ligularis is most likely to be imported as seed, but also as cuttings or seedlings. Seeds may be difficult to identify, though seedlings and leafy cuttings should be identifiable by leaf characters.

Impact

P. ligularis is a vigorous climbing plant native to Mexico, Central America and northwest South America south to Bolivia. Valued for its edible fruit (second only to P. edulis) and ornamental flowers, it is commonly cultivated and has often escaped in the tropical highlands of Central and South America. P. ligularis has been introduced and cultivated in India, east and southeast Asia, Australia and New Zealand and several Pacific islands, and is invasive in Haiti, Jamaica, Hawaii, Singapore, Indonesia, Zimbabwe, the Galapagos Islands and Samoa. In New Caledonia it is a declared noxious weed and its introduction is prohibited. P. ligularis can impact farming by smothering vegetation and impeding access, and may be poisonous or unpalatable to livestock. It also invades natural mesic forests and other natural vegetation formations, where it can shade out understorey plants.


Source: cabi.org
Description

R. racemosus is a deciduous shrub;tender parts glandular;prickles recurved. Leaves odd-pinnate, to 12(16) x 8(10) cm, chartaceous;margin serrate;petiole to 5(7) cm;stipules adnate to petiole, to 6 mm, persistent;terminal leaflet ovate, acute, to 8 x 6 cm, often sublobulate;laterals ovate-lanceolate, 7 x 3.5 cm. Inflorescence axillary, few-flowered;peduncle 2 cm. Flowers 1 cm wide;pedicel to 1 cm;bracts subulate, 6 mm. Calyx-tube shallowly cup-shaped, with glandular hairs;lobes 5, ovate-acuminate. Petals 5, red, longer than sepals. Stamens numerous. Ovary glabrous;ovule 1. Fruits globose, 1 cm wide, purple (India Biodiversity, 2014).

Impact

R. racemosus is a fast-growing shrub occasionally planted as an ornamental and for its edible fruits. At present, this species has been listed as invasive only in Jamaica, where it is principally invading areas in montane rainforests in the Blue Mountains region. In Jamaica, R. racemosus grows vigorously and fruits abundantly forming “impenetrable thickets” that out-compete and displace native vegetation and impede the movement of native wildlife (Adams, 1972;Goodland and Healey, 1996;IABIN, 2014).


Source: cabi.org
Invasive species Senna alata Documentation
Title: Senna alata
Description

The following description is from Flora of China Editorial Committee (2016)

Impact

S. alata is a shrub or small tree that is used as an ornamental and a cultivated plant throughout its range (Irwin and Barneby, 1982;PROTA, 2016). The species is reported as escaping from cultivation and becoming a weed in pastures, disturbed areas, orchards, plantations and shrublands (Irwin and Barneby, 1982;ILDIS, 2016). Livestock do not eat it, so the species has the potential to spread rapidly without control (ILDIS, 2016). It is reported as invasive in Asia (Hong Kong, Philippines, Singapore), East Africa and Oceania (Australia, Cook Islands, Federated States of Micronesia, Fiji, French Polynesia, Galapagos Islands, Guam, Hawaii, Palau, Papua New Guinea, Samoa and Tonga) (PIER, 2016). It is regarded as a significant environmental weed in the Northern Territory of Australia (Weeds of Australia, 2016). Risk assessments prepared for both Australia and the Pacific classed it as high risk (PIER, 2016).


Source: cabi.org
Title: Senna alata
Invasive species Senna hirsuta Documentation
Title: Senna hirsuta
Description

The following description is taken from The Flora of China Editorial Committee (2017).

Impact

S. hirsuta is an herbaceous plant native to the Americas. It has been introduced into several countries in Asia, Africa and Oceania where it has naturalized. S. hirsuta typically colonises areas of disturbed land such as roadsides, waste land and riparian areas. Very little information is available with regards to the environmental impacts of this species, although it is listed as invasive in Queensland (Australia), South Africa and Eastern Africa. The closely related species S. obtusifolia and S. tora are both serious weeds worldwide. and S. hirsuta possesses similar attributes to those which make these species invasive.


Source: cabi.org
Title: Senna hirsuta
Description


The following description is modified from Clayton et al. (2006)

Impact

A. caryophyllea is a small grass species native to Europe and North and East Africa that grows in nutrient-poor habitats. By growing in dense colonies it can out-compete native plants and prevent their establishment (PIER, 2013). Although it has become fairly widespread in Europe, North Africa and Asia, as well as in the regions where it has been introduced, such as North America and Australasia, it is not often considered seriously invasive. However, Weeds of Australia (2013) suggested that its potential negative impact may have been underestimated, and in Victoria and Western Australia A. caryophyllea is reported as an environmental weed.

Hosts

Weeds of Australia (2013) reported that A. caryophyllea is a common component of the remnants of natural temperate grasslands in the southern tablelands region, an endangered ecological community in New South Wales and the Australian Capital Territories. A. caryophyllea and other similar species may be replacing or out-competing native annual or spring-flowering species here, and could be having a negative impact on native species richness and diversity.


Source: cabi.org
Description


Adapted from Flora of North America Editorial Committee (2014)

Impact

O. engelmannii is a species of cactus, and one of many Opuntia species that have been introduced from their native ranges in the Americas and become naturalized and invasive, particularly in Australia, southern and eastern Africa, and the Mediterranean region. However, O. engelmannii is also reported as a noxious weed in Texas and elsewhere in its native range, where it has undergone control for almost a century. Contrastingly, in other US states such as Arizona it is noted as potentially endangered. Noting new records (e.g. Saudi Arabia), further occurrences not yet reported in other countries are possible, and further spread is likely. However, where it is invasive in Australia and South Africa, it has been successfully brought under control, as with other Opuntia species, with the use of biological control agents.


Source: cabi.org
Invasive species Antigonon leptopus Long
Description


Perennial, fast-growing, woody vine that climbs using tendrils at the end of the inflorescence axes and attains 5-13 m in length. Stems are puberulent, pentagonal, with many lateral branches. Leaves are alternate, ovate, triangular-ovate, or almost lanceolate, chartaceous, 5-14.5 × 2-7 cm, the apex is acute or acuminate, the base is cordiform or truncate, and the margins are crenulate, sometimes ciliate. The upper surface of leaves is light green slightly shiny, puberulent, with the venation sunken;lower surface pale green, dull, puberulent or glabrous, with prominent venation;petioles are 1-5 cm long, reddish, puberulent, cylindrical or subwinged. Flowers are bisexual, in axillary racemes or terminal panicles, 10-20 cm long, terminating in a pair of spiral tendrils;pedicels 3-4(-10) mm long. The perianth is about 4-7 mm long, of 5 ovate or elliptical tepals, intense pink or white;staminal column 2-3 mm long, of the same colour as the tepals. The fruit is a 3-angle-achene, 5-8 mm long (Acevedo-Rodríguez and Strong, 2005).

Impact

A. leptopus is a perennial vine, cultivated as an ornamental for its showy flowers, but which when neglected can grow quickly over other vegetation, spreading beyond its area of introduction. As an invasive vine, it is included in the Global Compendium of Weeds (Randall, 2012) and classified as one of the most aggressive weeds occurring in tropical and insular ecosystems (Langeland et al., 2008;Burke and DiTommaso, 2011;PIER, 2012).


Source: cabi.org
Description

A. humilis is a perennial shrub, 1-2(-5) m tall, glabrous. Branchlets terete, 5-7 mm in diameter, glabrous. Petiole canaliculate, 6-10 mm;leaf blade obovate, elliptic, or rarely oblanceolate, 15-18 × 5-7 cm, leathery, glabrous, inconspicuously pellucid punctate, scrobiculate, base cuneate and minutely decurrent, margin entire, apex broadly acute to obtuse;lateral veins ca. 12 on each side of midrib, marginal vein absent. Inflorescences terminal, rarely terminating lateral branchlets, subumbellate or cymose in pyramidal panicles, 8-17(-20) cm. Flowers leathery, pink or purplish red, 5-6 mm. Pedicel 6-10 mm, approximately 1.5 cm in fruit. Sepals broadly ovate, 1-2 mm, glabrous, punctate, base subauriculate, margin entire, apex acute. Petals nearly free, broadly ovate or ovate, glabrous, inconspicuously pellucid or orange punctate, glabrous. Stamens subequalling petals;filaments about half of anther length;anthers oblong-lanceolate, punctate dorsally, apiculate. Pistil equaling petals;ovary punctate, glabrous;ovules numerous, in 3 series. Fruit dull red or purplish black, globose, approximately 6 mm in diameter, densely punctate (Flora of China Editorial Committee, 2015).

Impact

Ardisia humilis is an ornamental shrub that is native to southern China, the Philippines and Vietnam. It has been intentionally introduced in some tropical and subtropical regions of the world where it may escape from cultivation, becoming a potential problem in moist lowland areas. Currently, this species is only listed as invasive in Cuba and Florida, USA. Most Ardisia species (including A. humilis) produce fleshy fruits that are consumed and dispersed by birds and small mammals, and are shade tolerant species with the potential to form monospecific stands in moist areas displacing native vegetation.


Source: cabi.org
Invasive species Aristida ternipes Long
Description

Perennial grass;cespitose. Culms 25-120 cm, wiry, erect to sprawling, unbranched. Leaves basal and cauline;sheaths usually longer than the internodes, glabrous;collars glabrous or strigillose;ligules less than 0.5 mm;blades 5-40 cm long, 1-2.5 mm wide, flat to folded, straight to lax at maturity, adaxial surfaces with scattered, 1.5-3 mm hairs near the ligule. Inflorescences paniculate, 15-40 cm long, (8)10-35(45) mm wide;rachis nodes glabrous or strigillose;primary branches 5-25 cm, remote, stiffly ascending to divaricate, with axillary pulvini, usually naked near the base;secondary branches and pedicels usually appressed. Spikelets usually congested. Glumes subequal, 9-15 mm, 1-veined, acuminate;calluses 1-1.2 mm;lemmas 9-15 mm long, smooth to tuberculate-scabrous, narrowing to slightly keeled, usually not twisted, 0.1-0.2 mm wide apices, junction with the awns not evident;awns unequal or almost equal, not disarticulating at maturity;central awns 8-25(30) mm, straight to arcuate at the base;lateral awns absent or to 0-23 mm;anthers 3, 1.2-2.4 mm. Caryopses 6-8 mm, light brownish (Allred, 2003).

Impact

Currently, A. ternipes is only listed as introduced and invasive in Cuba (Oviedo Prieto et al., 2012). However, because this species behaves as a weed in areas within its native distribution range, its occurrence is commonly associated with habitat and soil disturbances (Allred, 2003).


Source: cabi.org
Description


The following description is taken from Acevedo-Rodriguez, 2005:
Slightly woody vine, twining, attaining 5 m in length. Stems cylindrical, slender, glabrous, with the pith hollow. Leaves alternate;blades 5-16 x 6-18 cm, broadly ovate, reniform or orbicular, chartaceous, with prominently reticulate venation, the apex obtuse or rounded, the base deeply cordate, the margins entire;upper surface dark green, dull;lower surface glaucous, glabrous, with numerous scattered dots;petioles 3-11 cm long, sulcate or compressed, broadened at the base;pseudostipules foliaceous, ovate-rounded, 2.5-5 cm long. Flowers solitary, pendulous;peduncle 7.5-17 cm long;utricle obovoid, 5-7 x 2.5-4 cm, the tube straight, 3-4 cm long, almost forming a right angle with the utricle;limb bilabiate, yellowish with a cardinal red reticulum, the upper lip spathulate, 6-9 cm long, the lower lip lanceolate, 10-15 cm long. Capsule 6-11 cm long, oblong or oblanceolate, with 6 ribs, the apex mucronate, the base acute;seeds numerous, rhomboid, winged, 7-15 mm long.

Impact

A. ringens is a perennial twining plant listed in the global Compendium of Weeds as “cultivation escape, environmental weed, garden thug, naturalized, sleeper weed, weed” (Randall, 2012). It received a PIER risk score of 4 with a recommendation for further evaluation, where a score above 6 indicates its invasiveness (PIER, 2015). As an evergreen, perennial climbing vine, A. ringens grows quickly, producing numerous winged seeds adapted for wind dispersal (Acevedo-Rodriguez, 2005). Aristolochia species can also propagate vegetatively (Bailey and Bailey, 1976;Starr et al., 2003). The species is widely cultivated as an ornamental on account of its showy flowers. It is known to escape from cultivation (Liogier and Martorell, 2000;Meerman, 2003;Acevedo-Rodriguez, 2005;Randall, 2012), is weedy in parts of Central Africa (Randall, 2012), and has been reported to be invasive in Cuba (Oviedo-Prieto et al., 2012).


Source: cabi.org
Invasive species Arundo donax
Title: Arundo donax
Description

A. donax is a tall, erect, perennial cane- or reed-like grass. One of the largest herbaceous grasses, it can grow to 2-10 m tall. Its root structure is very strong, with the fleshy, almost bulbous, creeping rootstocks (rhizomes) forming compact bundles from which grow the fibrous roots, penetrating deep into the soil. The horizontal rhizomes give rise to many-stemmed, hollow, cane-like clumps allowing it to form large colonies many metres across. These tough, individual stems or culms are divided by partitions at the nodes like in bamboo, each node 12-30 cm in length and can reach diameters of 1-4 cm with walls 2-7 mm thick. They commonly branch during the second year of growth, rarely multiple, just single lateral branches from nodes. The outer tissue of the stem is of a silicaceous nature, hard and brittle with a smooth glossy surface that turns pale yellow when the culm is fully mature. The pale, blue-green leaves clasp the stem broadly with a heart-shaped, hairy-tufted base, 2-6 cm wide at the base and tapering to a fine tip, up to 70 cm or more in length. The leaves are arranged alternately throughout the culm and very distinctly two-ranked, in a single plane. The culms can remain green throughout the year but often fade with semi-dormancy during the winter or in droughts. The flowers are borne in large plume-like panicles, 30-65 cm, at the upper tips of stems between March and September and are closely packed in a cream to brown-coloured cluster. The spikelets, flowering units comprised of one or more florets enclosed by two bracts or glumes, are several flowered, approximately 12 mm long with florets becoming successively smaller. The segmented central axis of the spikelet, the rachilla, is glabrous and dis-articulates above the glumes and between the florets. The more or less unequal glumes are 3-nerved membranous, narrow, slender, pointed and as long as the spikelets. Lemmas, the larger, outer, bract which, along with the palea, serves to contain the florets held within, are thin, 3-nerved and covered with fine, soft hair. They are narrowed upwards with the nerves ending in slender teeth.

Impact

A. donax is an aggressive species with an ability to reproduce quickly, allowing it to out-compete native plant species, and has established itself as one of the primary threats to native riparian habitats in its introduced range, dramatically altering ecological and successional processes and altering habitats towards dense, monotypic stands up to 8 m tall. It is listed as one of the 100 world’s worst invasive alien species (ISSG, 2011). This species represent a serious concern in arid and semiarid habitats because it outcompete native vegetation in the access to soil-water. It uses more water than native plants, lowering groundwater tables. A. donax is highly flammable and can change fire regimes in invaded areas (USDA-ARS, 2014).

Hosts

A. donax is not usually a weed of crops, rather tending to out-compete and displace native vegetation in riparian habitats. However, it has been reported as invasive in pasture/cropland in South Africa, Tanzania, Egypt, Argentina, Uruguay, Chile, Puerto Rico, and the Dominican Republic (ISSG, 2007;Randall, 2012).


Source: cabi.org
Title: Arundo donax
Invasive species Brachypodium distachyon Long
Description

B. distachyon is an erect annual grass. Culms geniculately ascending, or decumbent;3-40 cm long. The following is adapted from Cal-IPC (2016) and Clayton et al. (2016).

Impact

B. distachyon, commonly known as purple false brome, is a grass species that is related to the major cereal grain species. It is native to southern Europe, northern Africa and southwestern Asia east to India but is widely introduced and naturalized elsewhere. It occurs broadly as an alien species throughout North America and has been reported as invasive in China, Chile, Australia and California. Brachypodium species are invasive weeds that dominate areas where they are planted or have become established and this species can equally form dense stands, reducing diversity and preventing the establishment of native species. The California Invasive Plant Council (Cal-IPC) classifies its potential impact on native ecosystems as ‘Moderate’.


Source: cabi.org
Invasive species Callisia repens Long
Description


Perennial, prostrate, slender, creeping herb, the often purplish stems rooting at the nodes and often forming mats. Leaves are ovate, 1-4 cm long;1-2 cm broad, acute at apex, rounded to sub-cordate at base, sessile, sub-succulent, glabrous except for ciliate margins;pale green;sheath tubular, 3-3.5 mm long, with a few long hairs at apex. Flowering in branches often somewhat ascending with leaves progressively smaller;flowers-clusters barely exserted beyond the sheaths in leaf-axils;bracts filiform, ciliate, 6-7 mm long. Sepals 3, linear lanceolate, greenish, 2-5 mm long, minutely pubescent;petals 4, oblong, whitish hyaline, slightly shorter than or equaling the sepals;stamens exserted, typically 3, but may vary in number from 0 to 6;filaments minutely ribbon-like, coiled at first, to 10 mm long;anthers rounded-elliptic or elliptic, basal on a reniform white connective ca. 0.5 mm long. Ovary 2-locular, pilose at apex, style filiform, up to 4.5 mm long, the stigma trifid (Howard, 1979) or penicillate (Hunt, 1983), 2 ovules per locule. Fruit is a lenticular capsule, approximately 1.7 mm long, splitting from apex to base;seeds 2 per valve, brown, approximately 1 mm, rugose (Acevedo-Rodríguez and Strong, 2005).

Impact

C. repens is an herbaceous species which has been widely cultivated as an ornamental in gardens and yards in tropical and subtropical regions from where it has escaped into natural areas. C. repens spreads vegetatively by cuttings, plant fragments, and/or discarded plants (Acevedo-Rodríguez and Strong, 2005). Once established, this species grows forming dense groundcover or “beds” on the forest floor preventing the germination and establishment of native plants. C. repens is listed as an invasive in South Africa, China, and Cuba (Foxcroft et al., 2007;Flora of China Editorial Committee, 2012;González-Torres et al., 2012), and it is also a common weed in Puerto Rico and US Virgin Islands (Más and Lugo, 2013).


Source: cabi.org
Invasive species Cichlasoma urophthalmum
Description


The following description is adapted from Page and Burr (1991);Martínez-Palacios and Ross (1992);Miller et al. (2005);Nico et al. (2007);Froese and Pauly (2016);Global Invasive Species Database (2016);Robins (2016) and Schofield et al. (2016).

Impact

The Mayan cichlid fish, C. urophthalmum, is a medium-sized cichlid native to Central America that is kept worldwide as an ornamental fish. Introduced populations are established in the Florida peninsular, USA and also in Thailand and Singapore. C. urophthalmum has become established in aquatic habitats because of its wide environmental tolerances, ability to colonize disturbed habitats, trophic opportunism, fast growth rates and advanced parental care of offspring. C. urophthalmus inhabits freshwater marshes and mangrove swamps, but prefers coastal lagoons and rivers and the species is highly tolerant of a wide range of salinities and will reproduce in freshwater and saltwater. It is a generalist predator and potential ecological impacts upon endemic fish fauna may include resource competition and predation, and predation of aquatic invertebrate communities that impacts upon ecosystem function. When breeding, C. urophthalmum becomes aggressive as territories are established on the substrate and defended against intruders.


Source: cabi.org
Invasive species Cortaderia jubata Documentation
Description

C. jubata is a large tussock grass that can grow to over 2.5m in height. Individual plants can be huge and their diameters gradually increase with age;they become hollow in the centre. Popay et al (2004) in New Zealand measured clumps of the related C. selloana up to 6m across. In that environment, most plants were smaller (less than 2m across), although 20 to 30 % of the plants measured were greater than 2m across.

Impact

C. jubata is a large tussock grass, native to South America, which has been introduced elsewhere as an ornamental plant and, in some countries, for forage, shelter or erosion control. It has naturalised and become established in Australia, New Zealand, South Africa and the USA, and is regarded as a very serious invasive species;it forms dense stands that displace native vegetation, and has become a serious problem in new forestry areas where it suppresses the growth of young trees and creates a fire hazard.

Biological Control
<br>Biological control of grass species has rarely been attempted because of the danger of damaging desirable grass species. In New Zealand, despite the possibility of collateral damage to native Austroderia species, the Sustainable Farming Fund (2011) has been funding the search for possible agents;a black smut fungus and a fly which attack the flowerheads seem to be quite damaging on Ecuadorian plants, but no reports on their identification have been published as yet.

Source: cabi.org
From Wikipedia:

An invasive species is a non-native species that spreads from the point of introduction and becomes abundant.

The invasive species label attaches only to populations of species whose impact upon introduction has altered their new environment. Although this impact can be beneficial, the term as most often used applies to introduced species that affect the invaded habitats and bioregions adversely, causing ecological, environmental, or economic damage. This includes plant species labeled as "exotic pest plants" and "invasive exotics" growing in native plant communities. The term is also used by land managers, botanists, researchers, horticulturalists, conservationists, and the public for noxious weeds.

The term "invasive" is poorly defined and often very subjective, and some broaden the term to include indigenous or "native" species that have colonized natural areas – for example deer considered by some to be overpopulating their native zones and adjacent suburban gardens in the Northeastern and Pacific Coast regions of the United States. The definition of "native" is also sometimes controversial. For example, the ancestors of Equus ferus (modern horses) evolved in North America and radiated to Eurasia before becoming locally extinct. Upon returning to North America in 1493, during their human-assisted migration, it is debatable as to whether they were native or exotic to the continent of their evolutionary ancestors.

Invasion of long-established ecosystems by organisms is a natural phenomenon, but human-facilitated introductions have increased massively the rate, scale, and geographic range of invasion. For millennia, humans have served as both accidental and deliberate dispersal agents, beginning with our earliest migrations, accelerating in the age of discovery, and accelerating again with international trade. Notable examples of invasive plant species include the kudzu vine, Andean pampas grass, and yellow starthistle. Animal examples include the New Zealand mud snail, feral pig, European rabbit, grey squirrel, domestic cat, carp, and ferret. Some popular reference sources now name Homo sapiens, especially modern-age humans, as an invasive species, but broad appreciation of human learning capacity and our behavioral potential and plasticity argues against any such fixed categorization.

Invasive species are those plants, animals, and microbes not native to a region which, when introduced either accidentally or intentionally, cause economic or environmental harm or harm to human health. See Executive Order 13112 (February 1999).