Alternanthera philoxeroides
(alligator weed)

Pictures

Picture	Title	Caption	Copyright
Title Leaves and inflorescence Caption A. philoxeroides is characterized by dark-green waxy leaves, lance-shaped, opposite, 12-14 x 1.5-2.5 cm. Inflorescence white, ball-shaped, papery, 1.5 cm in diameter. Copyright Bill Parsons	Leaves and inflorescence	A. philoxeroides is characterized by dark-green waxy leaves, lance-shaped, opposite, 12-14 x 1.5-2.5 cm. Inflorescence white, ball-shaped, papery, 1.5 cm in diameter.	Bill Parsons
Title Growth habit Caption A. philoxeroides is a perennial herb which grows as an emerged, aquatic plant, rooted in the soil or in the substrate below shallow water. Copyright Bill Parsons	Growth habit	A. philoxeroides is a perennial herb which grows as an emerged, aquatic plant, rooted in the soil or in the substrate below shallow water.	Bill Parsons
Title Growth and spread in water Caption The plant usually roots in a solid substrate and spreads in a tangled mat over the water surface. Copyright Bill Parsons	Growth and spread in water	The plant usually roots in a solid substrate and spreads in a tangled mat over the water surface.	Bill Parsons
Title Alligator weed infesting river Caption Excessive growth of A. philoxeroides covers waterways affecting navigation, preventing access, disrupting flow and adversely affecting the aquatic flora and fauna, as in this river at Baton Rouge, Louisiana, USA. Copyright Bill Parsons	Alligator weed infesting river	Excessive growth of A. philoxeroides covers waterways affecting navigation, preventing access, disrupting flow and adversely affecting the aquatic flora and fauna, as in this river at Baton Rouge, Louisiana, USA.	Bill Parsons

Identity

Preferred Scientific Name

• Alternanthera philoxeroides (Mart.) Griseb.

Preferred Common Name

• alligator weed

Other Scientific Names

• Achyrantes philoxeroides (Mart.)
• Achyranthes paludosa Bunbury
• Alternanthera philoxerina Suess.
• Bucholzia philoxeroides Mart.
• Celosia amphibia Salzm. ex Moq.
• Mogiphanes philorexoides D. Parodi
• Telanthera philoxeroides (Mart.)
• Telanthera philoxeroides (Mart.) Moq.

International Common Names

• English: alligator grass; pig weed
• Spanish: hierba caiman; hierba lagarto; lagunilla; yerba lagarto
• Chinese: xi han lian zi cao
• Portuguese: erva jacare; periquito-saracura; piriquito

Local Common Names

• Argentina: lagunilla
• Australia: mukuna-menna; pannankarni
• Brazil: erva de jacare
• Ecuador: hierba lagarto
• India: phackchet
• Mexico: hierba caimán; hierba del Caiman
• Sri Lanka: kimbul-wenna
• Uruguay: raiz colorado
• USA: alligatorweed

EPPO code

• ALRPH (Alternanthera philoxeroides)

Summary of Invasiveness

A. philoxeroides is one of the worst weeds in the world because it invades both terrestrial and aquatic habitats. The aquatic form of the plant has the potential to become a serious threat to rivers, waterways, wetlands and irrigation systems. The terrestrial form grows forming dense mats with a massive underground rhizomatous root system (ISSG, 2016). This weed is extremely difficult to control, is able to reproduce from plant fragments and grows in a wide range of climates and habitats, including terrestrial areas. In aquatic habitats it has deleterious effects on other plants and animals, water quality, aesthetics, vector populations, water flow, flooding and sedimentation. In terrestrial situations, it degrades riverbanks, pastures, and agricultural lands producing massive underground lignified root systems penetrating up to 50-60 cm deep. Currently, A. philoxeroides is listed as invasive in the United States, Puerto Rico, France, Italy, India, Sri Lanka, China, Taiwan, Indonesia, Myanmar, Singapore, Australia and New Zealand (Weber et al., 2008; Chandra, 2012; Rojas-Sandoval and Acevedo-Rodriguez, 2015; DAISIE, 2016; USDA-ARS, 2016; USDA-NRCS, 2016; Weeds of Australia, 2016).  Once established, it behaves as an aggressive invader with the capability to totally disrupt natural aquatic ecosystems, shoreline vegetation and terrestrial and semi-aquatic environments (ISSG, 2016; USDA-NRCS, 2016).

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Caryophyllales
•                         Family: Amaranthaceae
•                             Genus: Alternanthera
•                                 Species: Alternanthera philoxeroides

Notes on Taxonomy and Nomenclature

The family Amaranthaceae includes 174 genera and about 2500 species distributed worldwide especially in warm and dry temperate areas, the subtropics and saline habitats (Stevens, 2012). Alternanthera is a diverse genus (80–200 species) and the second largest in the subfamily Gomphrenoideae of Amaranthaceae.  The genus is largely restricted to the American tropics and its highest diversity occurs in South America, but many species also occur in the Caribbean, Central America and Mexico (Sanchez del Pino et al., 2012).

There are two biotypes of A. philoxeroides in Florida which differ morphologically: broad- and narrow-stemmed forms. Another two biotypes exist in Argentina which are morphologically similar but differ in chromosome number, the wild form being tetraploid (2n=68) and the weedy form being hexaploid (2n=102) (Parsons and Cuthbertson, 1992).

Description

Decumbent or ascending glabrate aquatic perennials, the simple or branched, often fistulose stems to 100 cm. long. Leaves glabrous or glabrate, lanceolate to narrowly obovate, apically rounded to acute, basally cuneate, rarely denticulate, 2-10 cm. long, 0.5-2 cm. broad; petioles 1-3 mm. long. Inflorescences of terminal and occasionally axillary white glomes, 10-18 mm. long, 10-18 mm. broad, the usually unbranched peduncles 1-5 cm. long. Flowers perfect, bracts and bracteoles subequal, ovate, acuminate, 1-2 mm. long; sepals 5, subequal, oblong, apically acute and occasionally denticulate, neither indurate nor ribbed, 5-6 mm. long, 1.5-2.5 mm. broad; stamens 5, united below into a tube, the pseudostaminodia lacerate and exceeding the anthers; ovary reniform, the style about twice as long as the globose capitate stigma. Fruit an indehiscent reniform utricle 1 mm. long, 1-1.5 mm. broad (Flora of Panama, 2016).

Plant Type

Distribution

A. philoxeroides is native to South America, principally the Parana River region (Julien et al., 1995), from Guyana to Brazil and northern Argentina (USDA-ARS, 2016). It has been introduced into Europe, North and Central America, the Caribbean, tropical Asia, and Oceania (DAISIE, 2016; ISSG, 2016 OEPP/EPPO, 2016; USDA-ARS, 2016). 

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

History of Introduction and Spread

In the USA, A. philoxeroides was probably introduced in contaminated ship ballast water, with the earliest herbarium specimen dating from South Carolina in 1885. In 1894 it arrived in Florida and in 1897 it was collected near Mobile, Alabama. By the early 1900s, it was recognized as a threat, but became a major threat after 1945 when chemical control of water hyacinth became effective and allowed A. philoxeroides to flourish (Coulson, 1977; Langeland et al., 2008). Now it is considered one of the worst aquatic weeds invading southern states (USDA-NRCS, 2016).

A. philoxeroides is present in Asia where it is widespread principally across warm temperate regions. In Sri Lanka A. philoxeroides was identified in 1998 and by 2004 it reached provinces at elevations > 2500 m (Jayasinghe, 2008). In China it is spreading across Beijing, Fujian, Guangxi, Hebei, Hubei, Hunan, Jiangsu, Jiangxi, Sichuan, Taiwan, and Zhejiang where it is causing serious impacts on aquatic habitats and famous scenic areas (Flora of China Editorial Committee, 2016). In India, A. philoxeroides is spreading across Assam, Bihar, West Bengal, Tripura, Manipur, Andhra Pradesh, Karnataka, Maharashtra, Delhi and Punjab. By 2008, A. philoxeroides was reported invading Wular Lake, the largest freshwater lake in India (Masoodin and Khan, 2012).

In Australia A. philoxeroides arrived during the 1940s, probably in ships' ballast (Julien and Broadbent, 1980). From initial sites at Botany Bay and Newcastle harbour, it had, by 1979, spread to the Lower Hunter River Valley and to near Albury (Julien et al., 1979). It was also found in backyard gardens of some Asian community groups in Australia who grew it as a leafy vegetable by mistake. It has been used since the 1960's and is now found in all Australian states and territories. The State of Victoria has the highest number of backyard plots (more than 800) of alligator weed in Australia (Gunasekera and Adair, 1999).

In New Zealand, it was first recorded in 1906 and now it can be found invading drains, streams, swamps and similar wet habitats across the country (Bassett et al., 2012; OEPP/EPPO, 2016).

In Europe, A. philoxeroides was first recorded in 1971 in France. Initially this species was confined to the southwest of France between the middle of the Gironde Estuary and the middle course of the River Garonne. However in the 2000s new populations were found on the Tarn River and in Sorgues (Provence) in 2013. In Italy A. philoxeroides was discovered in 2001 near Pisa, Tuscany. Currently, this species can also be found along the Arno River from Signa to Florence, in Lazio, and in Rome along the Tevere River (OEPP/EPPO, 2016). 

Risk of Introduction

The risk of introduction of A. philoxeroides is very high. Because this species is able to grow in both aquatic and terrestrial habitats, grows vigorously and spreads from floating fragments, it has a great potential to increase its present distribution into new areas. According to Julien et al. (1995) much of Africa, Asia and southern Europe provide a suitable habitat for this weed.

Liu et al. (2017) modelled the potential for further spread of invasive aquatic weeds following China’s South to North Water Diversion project, and predict that A. philoxeroides has high potential for northward range expansion in China.

Habitat

A. philoxeroides grows as a weed in both aquatic and terrestrial habitats, and often grows at the interface between these two environments (OEPP/EPPO, 2016). In natural and semi-natural habitats it is prone to become invasive principally in forests, riverbanks and wetlands. It can be found growing along canals, rivers, swamps, lakes, dams, ditches, and wetlands, being rooted to the ground and emerging above the water surface. However, it can also be found in riparian habitats free-floating in dense mats on the water surface. A. philoxeroides is also an important weed of wetter pastures and irrigated crops (ISSG, 2016; USDA-NRCS, 2016; Weeds of Australia, 2016).   

Habitat List

Hosts/Species Affected

A. philoxeroides primarily affects floating aquatic plants and pastures but submerged and emerged aquatic plants are also affected.

Host Plants and Other Plants Affected

Growth Stages

Biology and Ecology

Genetics

It has been suggested that the populations of A. philoxeroides within and outside its native distribution range are composed of a complex of hybrids. Consequently, the chromosome number for A. philoxeroides differs among populations with reports varying from 2n=66 to 2n=100 (Xu et al., 1992; Sosa et al., 2008).

Reproductive Biology

A. philoxeroides reproduces both sexually and asexually within its native distribution range, but propagates primarily through vegetative means in its introduced range. In this species, traits associated with sexual reproduction become degraded for sexual dysfunction, with flowers possessing either pistillate stamens or male-sterile anthers. Degradations of sexual characters for loss of sexuality commonly take place in clonal plants; such is the case of A. philoxeroides populations spreading mainly by vegetative (clonal) propagules (Zhu et al., 2015).

Physiology and Phenology

A. philoxeroides is a perennial, fast-growing, amphibious herb (ISSG, 2016.) Maximum growth of A. philoxeroides occurs during the warmer summer months with growth initiating from parent stock, usually rooting in a solid substrate and spreading in a tangled mat over the water surface. In early winter, emergent stems lose many leaves and become prostrate forming part of the mat that supports the next season's growth. Flowering occurs from mid to late summer (Julien and Broadbent, 1980). The plant does not always set viable seed under natural conditions; but reproduces vegetatively from axillary buds at each node (Julien and Broadbent, 1980).

Activity Patterns

A. philoxeroides grows as an emerged, aquatic plant, rooted in the soil or in the substrate below shallow water. Roots are short and filamentous in water, rising mainly from the nodes. It also grows in terrestrial habitats where its high growth-rates allow it to displace native vegetation and easily become the dominant species. This plant has an amazing ability to grow vigorously forming a massive underground rhizomatous root system that is difficult to control. When growing in terrestrial conditions, this species can survive without any water for several months (Gunasekera and Adair, 2000).

Environmental Requirements

A. philoxeroides prefers to grow at temperatures around 30°C, and growth is suppressed at temperatures below 7°C. However, the species can tolerate mean annual temperatures ranging from 10 to 20°C (OEPP/EPPO, 2016). The photosynthetic optimum for this species occurs between 30°C and 37°C and light saturation at 1000 μmol photons m^-2 s^-1 (OEPP/EPPO, 2016), but it can adapt to low light conditions (Weber, 2003). It can tolerate cold winters, but cannot survive prolonged freezing temperatures (Langeland et al., 2008). It has been observed growing in water with pH ranging from 4.8 and 7.7 and it is fairly salt tolerant and can survive in upper tidal beaches and other saline conditions (10-30% that of sea water). A. philoxeroides grows well in high-nutrient (eutrophic) conditions, but can survive in areas with low nutrient availability  (Weber, 2003; Langeland et al., 2008).

Climate

Air Temperature

Rainfall

Rainfall Regime

Soil Tolerances

Soil drainage

• free
• impeded
• seasonally waterlogged

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• heavy
• light
• medium

Special soil tolerances

• infertile
• shallow
• sodic

Water Tolerances

Natural enemies

Notes on Natural Enemies

During South American explorations for biological control agents, over 40 arthropod species were found to feed on A. philoxeroides (Coulson, 1977). The flea beetle Agasicles hygrophila can cause considerable damage to the aquatic form of A. philoxeroides by eating the leaves and boring into the stem, where it pupates. The thrip species Amymothrips andersoni produces limited damage to the stands by attacking and deforming the apical leaves. The stem borer Arcola malloi (formerly Vogtia malloi)) is a small moth that lays its eggs on the apical leaves. The larvae bore into the stem and work their way down the stem, resulting in wilting and drooping of the plant (DiTomaso and Kyser, 2013).

Means of Movement and Dispersal

Natural Dispersal (Non-Biotic)

A. philoxeroides spreads by seeds and vegetatively by root and stem fragments. However, because seeds are generally not produced in areas outside its native distribution range, most reproduction is vegetative. Fragments are commonly spread downstream by waterways and floods and new plants develop rapidly from any piece of stem or root material containing a node (Langeland et al., 2008; ISSG, 2016; Weeds of Australia, 2016).

Accidental Introduction

A. philoxeroides has been accidentally introduced in the ballast of ships. Stem and root fragments, which have the ability to float, are easily dispersed by floods and water currents. Stem and root fragments can also be dispersed by boats, vehicles, in dumped garden waste, and by animals (ISSG, 2016; Weeds of Australia, 2016). A. philoxeroides seed has been found in Europe as a contaminant in bird seed originating from outside the EU, and seedlings have been found contaminating bonsai plants imported from China (OEPP/EPPO, 2016).

Intentional Introduction

A. philoxeroides has been intentionally introduced by humans to be used as an aquarium plant and ornamental aquatic plant (USDA-ARS, 2016). 

Pathway Causes

Pathway Vectors

Wood Packaging

Impact Summary

Economic Impact

A. philoxeroides is a problem in 30 countries. It is a serious weed in eight of these and a major weed in the others. It threatens the turf industry in the Sydney basin, Australia, and the vegetable industry in the Hawkesbury Nepean catchment. The plant can be a problem in rice paddies (Waterhouse, 1993) and is seen as a major threat to rice crops in southwestern New South Wales (Weeds of Australia, 2016). It has been estimated that the costs to agriculture in New South Wales could be as high as Aus$250 million per annum if the species was to reach its potential distribution in this state (Weeds of Australia, 2016).

On land, it invades and competes with pastures and this provides a source of further spread. Although it is grazed by cattle in Australia, it is not considered desirable in pastures (Julien and Chan, 1992) and is a declared noxious weed in all mainland states and territories (Parsons and Cuthbertson, 1992) as well as a weed of national significance in Australia (Thorpe, 1999).

A. philoxeroides infestations have been reported to reduce production of rice by 45%, wheat by 36%, maize 19%, sweet potato 63% and lettuce 47% (OEPP/EPPO, 2016). On average vegetable production is reduced by 5-15% (www.weeds.org.au/natsig.htm).

A. philoxeroides mats impede stream flow and lodge against structures thereby promoting sedimentation which contributes to flooding and structural damage. Infestations can disrupt recreational activities including boating, fishing and swimming.

Environmental Impact

A. philoxeroides is considered to be one of the worst aquatic weeds in the world. The aquatic form of the plant has the potential to become a serious threat to waterways, agricultural lands and the natural environment. The terrestrial form grows into a dense mat with a massive underground rhizomatous root system. This species has the potential to completely disrupt aquatic environments by blanketing the surface of the water impeding light penetration and gaseous exchange with adverse effects on flora and fauna (ISSG, 2016). A. philoxeroides also promotes sedimentation and flooding leading to a reduction in water quality (i.e. reduced oxygen levels in the water). When growing on land it also grows forming a dense mat of vegetation with a mass of creeping underground stems and is capable of out-competing all but the most robust plant species. It quickly displaces native plants and can be harmful to the native animals that rely on them (Weeds of Australia, 2016).

Impact on Biodiversity

In China, A. philoxeroides has been shown to decrease the stability of the plant community and, over time, permanently displace native species (Guo and Wang, 2009). In India, A. philoxeroides is reducing macrophyte species richness by up to 30% when the infestation was high. In New Zealand, an increasing cover of A. philoxeroides decreased the cover of native plant species, resulting in loss of native species (Bassett et al., 2012). In a study at different latitudes in China, small-scale invasion of A. philoxeroides was associated with higher species diversity, but community diversity was lower when A. philoxeroides species cover exceeded 36% (Wu et al., 2016). Zhang et al. (2010) also demonstrate reduced plant species diversity in severely invaded communities.

In Australia, A. philoxeroides is already an important environmental weed invading New South Wales, Victoria and Queensland. It is regarded as one of the worst weeds in Australia where it is currently having the greatest impact in New South Wales, where the total infested area is now estimated at 3,950 hectares. A. philoxeroides has also been found at several hundred sites in Victoria and is listed among the top 50 most invasive plant species in Queensland (Weeds of Australia, 2016). In New Zealand it is also noted to be harmful to native biodiversity and it is replacing most other herbaceous species on water and dry land. It also causes silt accumulation, obstructs water usage, and causes flooding. Rotting vegetation degrades habitats for native aquatic fauna and flora.

In the United States, A. philoxeroides is considered to be one of the worst aquatic weeds and is listed as a noxious weed in 15 states (USDA-NRCS, 2016). In southern states such as Florida and South Carolina it grows forming dense tangled mats that overtop native aquatic plants and out-compete them for sunlight. It eventually replaces desirable native species and can significantly alter the aquatic and riverine ecology of heavily infested areas. This species also invades drains, streams, swamps and similar wet habitats (USDA-NRCS, 2016). 

Social Impact

Thick mats of A. philoxeroides prevent access to and use of water, cause health problems by providing habitats for mosquitoes and degrade natural aesthetics. Also, the thick mats of the weed create a dangerous hazard for swimming, boating, rowing and other water sports. Excessive growth of A. philoxeroides affects irrigation and fisheries; it also covers waterways affecting navigation, preventing access, disrupting flow and adversely affecting the aquatic flora and fauna (Julien and Chan, 1992). Cultural services can be degraded by the infestation of scenic areas and waterbodies by A. philoxeroides (OEPP/EPPO, 2016).

The ability of A. philoxeroides to absorb heavy metals is a problem in countries such as Myanmar, Sri Lanka, Australia, and Philippines where it is used as food (Parsons and Cuthbertson, 1992).

Risk and Impact Factors

• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Highly mobile locally
• Long lived
• Fast growing
• Has high reproductive potential
• Has propagules that can remain viable for more than one year
• Reproduces asexually

• Altered trophic level
• Damaged ecosystem services
• Ecosystem change/ habitat alteration
• Infrastructure damage
• Modification of hydrology
• Modification of natural benthic communities
• Modification of nutrient regime
• Monoculture formation
• Negatively impacts agriculture
• Negatively impacts human health
• Negatively impacts animal health
• Negatively impacts livelihoods
• Negatively impacts aquaculture/fisheries
• Negatively impacts tourism
• Reduced amenity values
• Reduced native biodiversity
• Soil accretion
• Threat to/ loss of native species
• Transportation disruption

• Competition - monopolizing resources
• Competition - smothering
• Rapid growth
• Rooting

• Highly likely to be transported internationally accidentally
• Highly likely to be transported internationally deliberately
• Difficult to identify/detect as a commodity contaminant
• Difficult to identify/detect in the field
• Difficult/costly to control

Uses List

Animal feed, fodder, forage

• Fodder/animal feed

General

• Ornamental
• Pet/aquarium trade

Medicinal, pharmaceutical

• Traditional/folklore

Similarities to Other Species/Conditions

A. philoxeroides is superficially quite similar to A. sessilis, but the latter is only an annual species and the clusters of flowers are sessile in the leaf axils, not on peduncles. Members of the genus Ludwigia spp. may be confused with A. philoxeroides due to a similar growth habit (Flanagan, 1991; Julien and Broadbent, 1980). A. philoxeroides has a similar appearance to Persicaria decipiens (smartweed) and Tradescantia albiflora (wandering jew) in Australia (Gunasekera, 1999). Weeds of Australia (2016) lists differences between A. philoxeroides and several native and introduced species of Alternanthera. The native Australian joyweeds (e.g. Alternanthera denticulata and Alternanthera nana) can be easily distinguished from terrestrial A. philoxeroides plants by the fact that their whitish flower clusters are stalkless.

The water primroses (Ludwigia adscendens and Ludwigia peploides subsp. montevidensis) often form similar dense mats of vegetation out over the water surface, but can be distinguished by their alternately arranged leaves, larger four-petalled flowers (about 25 mm across) and elongated fruit (Weeds of Australia, 2016).

Prevention and Control

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Prevention

In New Zealand, A. philoxeroides is included in the National Pest Plant Accord list, which bans the sale, propagation and distribution of the plant throughout New Zealand. In Australia, it is a prohibited species whose propagation and supply is prohibited, and legislation requires the species to be controlled and/or eradicated. In the USA, the species has varying classifications at federal or state levels (OEPP/EPPO, 2016).

Eradication

In 1992, A. philoxeroides was recorded and eradicated from Brisbane and Queensland (Parsons and Cuthbertson, 1992). An infestation in Canberra's Lake Ginninderra was also found and eradicated (Julien et al., 1995).

Control

Mechanical control

Mechanical control methods such as using a cookie cutter, flail chopper, hand removal, harvesting, hand cutter, or rotovation are good for clearing water ways, but unless all fragments of the stems are collected these management practices could exacerbate the problem. Since A. philoxeroides reproduces vegetatively, if any fragments move downstream they can develop into another colony ((DiTomaso and Kyser, 2013).

Mechanical harvesting and ploughing are not suitable control methods for A. philoxeroides because the weed is able to spread from cut stems and roots (Julien and Broadbent, 1980).

Biological control

A. philoxeroides has been the subject of successful biological control in the USA, Australia, New Zealand and Thailand. There is an extensive biocontrol programme in China. Partial control of the species has been achieved in New Zealand by biocontrol methods (Hayes et al., 2013).

Amynothrips andersoni, a biocontrol agent originally from Argentina, has been introduced into the USA; it is established in Florida, Georgia and South Carolina. It has been released in Alabama, California, Mississippi and Texas, but Julien (1992) could not confirm establishment in these states. Thayer and Pfingsten (2017) report that while biocontrol agents have been successful in managing A. philoxeroides in the USA, the effectiveness of A. andersoni is questionable as the insect is flightless and rarely seen on wild populations.

Agasicles hygrophila, another biocontrol agent originally from Argentina, has been introduced into other countries. In Australia, it is established and successfully controls A. philoxeroides in aquatic habitats. In New Zealand, it destroys most foliage of the weed annually. In Thailand, it has spread around Bangkok and the lower central plain area producing excellent control of A. philoxeroides. In the USA, this biocontrol agent is generally successful in controlling the weed in Florida, Louisiana and Texas; it is also well established in South Carolina, Georgia, Alabama and Mississippi (Julien, 1992). Thayer and Pfingsten (2017) say that this beetle along with other introduced insects has provided “exceptional control” of A. philoxeroides in the USA, but that the northern spread of the weed is beyond the range of A. hydrophila’s ability to overwinter. The beetle is, however, collected annually in St. Johns River in Florida to ship to areas of the country where the biocontrol agent does not overwinter and A. philoxeroides persists.

Tests of specificity of A. hygrophila in China have confirmed that the beetle cannot complete its life cycle on plants other than A. philoxeroides and Alternanthera sessilis (Lu et al., 2012; Zhao et al., 2013). Li and Ye (2006) suggest that Agiscles hygrophila has been successful in limiting growth of A. philoxeroides in water but not on land. Ma et al. (2013) report that since the first introduction of A. hygrophila from Florida to China in 1987, the genetic diversity of the control agent has decreased. It is suggested that genetic diversity should be considered in planning introduction and long-term maintenance of populations.

Arcola malloi (formerly Vogtia malloi) is also from Argentina and was introduced into Australia in 1977 where it has become established and spread through the aquatic habitat. It was released unsuccessfully in New Zealand in 1984, and again in 1987; it is now well established and reducing the spread of A. philoxeroides at three sites (Julien, 1992). In the USA, it is established in Arkansas, Florida, Louisiana, South Carolina and Texas. In Mississippi, it reduces floating mats by 50-90%, infestations are, however, uneven and may cycle over several years. Thayer and Pfintsten (2017) quote a 1992 publication by Vogt et al. suggesting that the stem borer A. malloi has produced more damage to A. philoxeroides in the interior regions of the weed’s adventive range than has Agasicles hygrophila in the southern and coastal regions. This insect is capable of migrating considerable distances and is the most cold tolerant of the insects used for biocontrol of A. philoxeroides.

Hymenia recurvalis removed between 25-50% of the leaf material of A. philoxeroides in the mid to late summer of 1976/1977, in the Sydney area of Australia. This was of little consequence as it was after most regrowth had occurred (Julien and Broadbent, 1980).

Candezea palmerstoni killed most of the stem tips of A. philoxeroides in several areas near Williamstown, New South Wales, Australia, in the summer of 1977/1978; the damage was not widespread and did not occur in succeeding seasons (Julien and Broadbent, 1980).

Three species (Hymenia recurvalis, Nanophyes sp. and Junonia lemonias), found feeding on A. philoxeroides in Thailand, were not sufficiently damaging to be considered useful as biological control agents (Napompeth, 1991).

Research in China has investigated the pathogenicity of fungal agents against A. philoxeroides, including Alternaria alternata (Zhou et al., 2016). Use of competing plants has also been studied. Cao et al. (2014) found that Humulus scandens strongly inhibited growth of A. philoxeroides, and suggest that as an annual herb H. scandens can then be eliminated by harvesting before its seeds mature.

Chemical control

A. philoxeroides is more resistant to herbicides than other aquatic macrophytes (Julien and Broadbent, 1980). Parsons and Cuthbertson (1992) reported control, but not eradication, of the weed in rice fields with herbicides including bentazone, bifenox, dicamba, fenoprop, pendimethalin, propanil and triclopyr, without causing serious damage to the crop; 2,4-D has only a temporary effect. Bowmer (1992) reported the following two treatments as effective against the weed: one application of dichlobenil followed 9 months later by metsulfuron; and three sprays over 18 months with metsulfuron or a metsulfuron/glyphosate mixture. However, certain treatments cannot be used close to waterbodies where there is the possibility of water being contaminated.

At Griffith, New South Wales, Australia, glyphosate was used on all aquatic areas, metsulfuron on terrestrial areas and dichlobenil in selected areas where terrestrial plants were growing in shallow ponded water (Milvain, 1995). The herbicides, metsulfuron methyl, glyphosate, dichlobenil and a mixture of glyphosate and metsulfuron methyl have been used to control  A. philoxeroides infestations in Australia. All naturalized sites associated with water were treated with glyphosate at three 2 monthly intervals (Gunasekera and Bonila, 2001). Dugdale et al. (2010) caution that herbicide treatment can leave viable stem fragments which are capable of colonization. Clements et al. (2014) report control of early invasion stages of A. philoxeroides in Australia using glyphosate or metsulfuron-methyl, followed by physical removal after initial treatment. Use of herbicides to control A. philoxeroides was reviewed by Dugdale and Champion (2012).
 

References

Abud JK, 1985. Effect of herbicide mixtures in the control of Echinochloa crus-galli (L.) Beauv. and Alternanthera philoxeroides (Mart.) Griseb. in irrigated rice. Lavoura Arrozeira, 38(358):12-15

Aston HI, 1973. Aquatic plants of Australia, Melbourne. Melbourne University Press.

Ather Masoodi; Khan FA, 2012. Invasion of alligator weed (Alternanthera philoxeroides) in Wular Lake, Kashmir, India. Aquatic Invasions [Proceedings of the 17th International Conference on Aquatic Invasive Species, San Diego, USA, 29 August-2 September 2010.], 7(1):143-146. http://www.aquaticinvasions.net/2012/AI_2012_1_Masoodi_Khan.pdf

Bambaradeniya C N B, 2000. Alien invasive species in Sri Lanka, Loris, 22(4):3-7.

Bassett I; Paynter Q; Hankin R; Beggs JR, 2012. Characterising alligator weed (Alternanthera philoxeroides; Amaranthaceae) invasion at a northern New Zealand lake. New Zealand Journal of Ecology, 36(2):216-222. http://www.nzes.org.nz/nzje/

Bowmer KH, 1992. Aquatic plant management in Australia (not necessarily weed control!). Proceedings of the 1st International Weed Control Congress., Vol. 2:95-98.

Cabrera N; Sosa A; Dorado J, 2007. Systena silvestrii Bechyné (Coleoptera: Chrysomelidae): redescription, new distribution and adult host records. Transactions of the American Entomological Society, 133(3/4):433-444.

Cao YuSong; Wang Ting; Xiao Yi'an; Zhou Bing, 2014. The interspecific competition between Humulus scandens and Alternanthera philoxeroides. Journal of Plant Interactions, 9(1):194-199. http://www.tandfonline.com/loi/tjpi20

Chandra SK, 2012. Invasive Alien Plants of Indian Himalayan Region- Diversity and Implication. American Journal of Plant Sciences, 3:177-184.

Chong KY; Tan HTW; Corlett RT, 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, 273 pp. http://lkcnhm.nus.edu.sg/nus/pdf/PUBLICATION/LKCNH%20Museum%20Books/LKCNHM%20Books/flora_of_singapore_tc.pdf

Clements D; Dugdale TM; Butler KL; Hunt TD, 2014. Management of aquatic alligator weed (Alternanthera philoxeroides) in an early stage of invasion. Management of Biological Invasions, 5(4):327-339. http://www.reabic.net/journals/mbi/2014/4/MBI_2014_Clements_etal.pdf

Clements D; Dugdale TM; Hunt TD, 2011. Growth of aquatic alligator weed (Alternanthera philoxeroides) over 5 years in south-east Australia. Aquatic Invasions, 6(1):77-82. http://www.aquaticinvasions.net/2011/AI_2011_6_1_Clements_etal.pdf

Coulson JR, 1977. Biological control of alligatorweed, 1959-1972. A review and evaluation. Technical Bulletin, Agricultural Research Service, United States Department of Agriculture, No. 1547:[6 +] 98 pp.

DAISIE, 2016. Delivering Alien Invasive Species Inventories for Europe. European Invasive Alien Species Gateway. www.europe-aliens.org/default.do

Das SKD; Singh NP, 2006. Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae) - further extended distribution in Maharashtra. Journal of Economic and Taxonomic Botany, 30(1):198-200.

DiTomaso JM; Kyser GB; Oneto SR; Wilson RG; Orloff SB; Anderson LW; Wright SD; Roncoroni JA; Miller TL; Prather TS; Ransom C; Beck KG; Duncan C; Wilson KA; Mann JJ, 2013. Weed Control in Natural Areas in the Western United States. Davis, California, USA: Weed Research and Information Center, University of California, 544 pp.

Dugdale TM; Champion PD, 2012. Control of alligator weed with herbicides: a review. Plant Protection Quarterly, 27(2):70-82. http://www.weedinfo.com.au

Dugdale TM; Clements D; Hunt TD; Butler KL, 2010. Alligatorweed produces viable stem fragments in response to herbicide treatment. Journal of Aquatic Plant Management, 48:84-91. http://www.apms.org/japm/vol48/vol48p084.pdf

EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm

Flanagan GJ, 1991. Alligator weed (Alternanthera philoxeroides). Agnote (Darwin), No. 469:2 pp.

Flora of China Editorial Committee, 2016. Flora of China. St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria. http://www.efloras.org/flora_page.aspx?flora_id=2

Flora of Panama, 2016. Flora of Panama (WFO), Tropicos website. Tropicos website. St. Louis, MO and Cambridge, MA, USA: Missouri Botanical Garden and Harvard University Herbaria. http://www.tropicos.org/Project/FOPWFO

Funk V; Hollowell T; Berry P; Kelloff C; Alexander SN, 2007. Checklist of the plants of the Guiana Shield (Venezuela: Amazonas, Bolivar, Delta Amacuro; Guyana, Surinam, French Guiana). Contributions from the United States National Herbarium, 584 pp.

Gangstad EO, 1977. Aquatic weed problems in Puerto Rico. Journal of Aquatic Plant Management, 15:3-5.

Garbari F; Pedullà ML, 2001. Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae), a new species for the exotic flora of Italy. (Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae), specie nuova per la flora esotica d'Italia.) Webbia, 56(1):139-143.

Gilbert RL; Auld BA; Hennecke BR, 2005. Leaf and stem spot of Alternanthera philoxeroides (alligatorweed) in Australia caused by Nimbya sp. Plant Pathology, 54(4):585. http://www.blackwell-synergy.com/servlet/useragent?func=showIssues&code=ppa

Grosse A, 1996. Flora and Fauna Catalog of Introduced Paraguay species. I3N - IABIN Invasive Information Network.

Gunasekera L, 1999. Alligator weed broacher, City of Casey (Victoria).

Gunasekera L, 1999. Alligator weed-an aquatic weed present in Australian backyards. Plant Protection Quarterly, 14(2):77-78.

Gunasekera L; Adair R, 1999. The alligator weed battle in Victoria, Proceedings of 12th Australian Weeds Conference, Hobart, Australia, September 12 to 16, 1999. 547-550.

Gunasekera L; Bonila J, 2001. Alligator weed: tasty vegetable in Australian backyards?. Journal of Aquatic Plant Management, 39:17-20.

Guo L; Wang T, 2009. Impact of invasion of exotic plant Alternanthera philoxeroides on interspecies association and stability of native plant community. Zhongguo Shengtai Nongye Xuebao/ Chinese Journal of Eco-Agriculture, 17:851-856.

Guo X; Zhou X, 2005. Molecular characterization of Alternanthera yellow vein virus: a new Begomovirus species infecting Alternanthera philoxeroides. Journal of Phytopathology, 153(11/12):694-696. http://www.blackwell-synergy.com/servlet/useragent?func=showIssues&code=jph

Hayes L; Fowler SV; Paynter Q; Groenteman R; Peterson P; Dodd S; Bellgard S, 2013. Biocontrol of weeds: achievements to date and future outlook. In: Ecosystem services in New Zealand: conditions and trends [ed. by Dymond, J. R.]. Lincoln, New Zealand: Manaaki Whenua Press, Landcare Research, 375-385.

Holm LG; Pancho JV; Herberger JP; Plucknett DL, 1979. A geographical atlas of world weeds. New York, USA: John Wiley and Sons, 391 pp.

Islam MM; Amin ASMR; Sarker SK, 2003. Bangladesh. In: PallewattaN, Reaser J, Gutierrez A, eds., Invasive Alien Species in South-Southeast Asia: National Reports & Directory of Resources. Cape Town, South Africa: Global Invasive Species Programme, 7-20.

ISSG, 2016. Global Invasive Species Database (GISD). Invasive Species Specialist Group of the IUCN Species Survival Commission. http://www.issg.org/database/welcome/

Jayasinghe H, 2008. Please don't eat mallung leaf lookalike. Sunday Times, Sri Lanka. http://www.sundaytimes.lk/080504/News/news0013.html

Julien MH; Broadbent JE, 1980. The biology of Australian weeds 3. Alternanthera philoxeroides (Mart.) Griseb. Journal of the Australian Institute of Agricultural Science, 46(3):150-155

Julien MH; Broadbent JE; Harley KLS, 1979. The current status of biological control of Alternanthera philoxeroides in Australia. In: Medd RW, Auld BA, ed. Proceedings of the seventh Asian-Pacific Weed Science Society conference, Sydney, Australia. November, 26 to 30, 1979. Asian-Pacific Weed Science Society. Australia, 231-233

Julien MH; Chan RR, 1992. Biological control of alligator weed: unsuccessful attempts to control terrestrial growth using the flea beetle Disonycha argentinensis (Col., Chrysomelidae). Entomophaga, 37(2):215-221.

Julien MH; ed, 1992. Biological control of weeds: A world wide catalogue of agents and their target weeds. 3rd edition. Wallingford, UK: CAB International.

Julien MH; Skarratt B; Maywald GF, 1995. Potential geographical distribution of alligator weed and its biological control by Agasicles hygrophila. Journal of Aquatic Plant Management, 33:55-60.

Khanna KK, 2009. Invasive alien angiosperms of Uttar Pradesh. Biological Forum, 1(2):34-39. http://www.researchtrend.net

Lal C; Sah M, 1990. Range extension of three exotic aquatic macrophytes in north India. Journal of the Bombay Natural History Society, 87(3):469.

Langeland KA; Cherry HM; McCormick CM; Craddock Burks KA, 2008. Identification and Biology of Non-native Plants in Florida's Natural Areas. Gainesville, Florida, USA: University of Florida IFAS Extension.

Li Jing; Ye WanHui, 2006. Genetic diversity of alligator weed ecotypes is not the reason for their different responses to biological control. Aquatic Botany, 85(2):155-158. http://www.sciencedirect.com/science/journal/03043770

Li LiYing; Wang Ren; Waterhouse DF, 1997. The distribution and importance of arthropod pests and weeds of agriculture and forestry plantations in southern China. The distribution and importance of arthropod pests and weeds of agriculture and forestry plantations in southern China., x + 185 pp.; [ACIAR monograph No. 46]; 5 pp. of ref.

Liao JianXiong; Tao Min; Jiang MingXi, 2014. Spatial arrangements affect suppression of invasive Alternanthera philoxeroides by native Hemarthria compressa. Acta Oecologica, 59:46-51. http://www.sciencedirect.com/science/journal/1146609X

Liu DaSheng; Wang Rui; Gordon DR; Sun XiHua; Chen Lu; Wang YanWen, 2017. Predicting plant invasions following China's water diversion project. Environmental Science & Technology, 51(3):1450-1457. http://pubs.acs.org/doi/abs/10.1021/acs.est.6b05577

Liu YuFang; Su WenJie; Zeng QiangGuo; Li Fei; Peng MeiFang; Peng JiaXing; Liu WenHai; Wan FangHao, 2011. Quantitative evaluation of the controlling effects of Agasicles hygrophila (Coleoptera: Chrysomelidae) on alligator weed (Alternanthera philoxeroides). Acta Entomologica Sinica, 54(11):1305-1311. http://www.insect.org.cn/EN/volumn/current.shtml

Lorenzi H, 1982. Weeds of Brazil, terrestrial and aquatic, parasitic, poisonous and medicinal. (Plantas daninhas de Brasil, terrestres, aquaticas, parasitas, toxicas e medicinais.) Nova Odessa, Brazil: H. Lorenzi, 425 pp.

Lou YuanLai; Shen JinLiang; Zhao YanCun, 2005. Distribution and damage of Alternanthera philoxeroides in agro-environment of Jiangsu Province. Journal of Anhui Agricultural University, 32(4):436-440.

Lu JunJiao; Zhao LongLong; Ma RuiYan; Fan RenJun; Zhang JinTong; Wang Ren, 2012. Non-target plant testing of the flea beetle Agasicles hygrophila, a biological control agent for Alternanthera philoxeroides (alligatorweed) in China. Biocontrol Science and Technology, 22(9):1093-1097. http://www.tandfonline.com/doi/full/10.1080/09583157.2012.708019

Lu ZhengRong; Shen JianYing; Lu YiTong, 2005. The community succession of rice field weeds in Shanghai area and factor analysis. Acta Agriculturae Shanghai, 21(1):82-86.

Ma RuiYan; Jia XiaoYun; Liu WenZhong; Laushman RH; Zhao LongLong; Jia Dong; Wang Ren, 2013. Sequential loss of genetic variation in flea beetle Agasicles hygrophila (Coleoptera: Chrysomelidae) following introduction into China. Insect Science, 20(5):655-661. http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1744-7917

Milvain H, 1995. Alligator weed - MIA campaign. Has it been a success?. Better planning for better weed management. Proceedings of the 8th biennial noxious weeds conference, Goulburn, NSW, Australia, 19-21 September 1995: volume 1., 87-89; [Agdex 640].

Napompeth B, 1991. Aquatic weed management by biological methods in Thailand. In: A Symposium on Aquatic Weed Management. Bogor, Indonesia, BIOTROP Special Publication, 40:51-61.

OEPP/EPPO, 2016. Alternanthera philoxeroides (Mart.) Griseb. European and Mediterranean Plant Protection Organization Bulletin, 46(1):8-13. https://www.eppo.int/QUARANTINE/data_sheets/plants/ALRPO_ds.pdf

Ou Jian; Lu ChangYi; O'Toole DK, 2008. A risk assessment system for alien plant bio-invasion in Xiamen, China. Journal of Environmental Sciences, 20(8):989-997. http://www.elsevier.com/wps/find/journaldescription.cws_home/709941/description#description

Pangtey YPS; Tewari LM; Kanchan Upreti, 2012. A note on the collection of Alternanthera pheloxeroides (Mart.) Griseb. from the foothills of Kumaun (Uttarakhand). Journal of Economic and Taxonomic Botany, 36(2):399-400. http://www.indianperiodical.in

Parsons WT; Cuthbertson EG, 1992. Noxious Weeds of Australia. Melbourne, Australia: Inkata Press, 692 pp.

Patel DP; Anup Das; Rajesh Kumar; Munda GC, 2005. Comparative study of photosynthesis and associated parameters in major crops and weed species in mid hills of Meghalaya. Annals of Plant Physiology, 19(1):1-4.

Paudel KC; Kaini BR, 2003. Nepal: sharing experiences from agricultural and forestry sectors. Invasive Alien Species in South-Southeast Asia:66-69. http://www.issg.org/pdf/publications/GISP/Resources/SEAsia-2.pdf

Ranjit JD; Suwanketnikom R, 2005. Response of weeds and yield of dry direct seeded rice to tillage and weed management. Kasetsart Journal, Natural Sciences, 39(2):165-173.

Rojas-Sandoval J; Acevedo-Rodríguez P, 2015. Naturalization and invasion of alien plants in Puerto Rico and the Virgin Islands. Biological Invasions, 17(1):149-163. http://rd.springer.com/article/10.1007/s10530-014-0712-3/fulltext.html

Sánchez-del Pino I; Motley TJ; Borsch T, 2012. Molecular phylogenetics of Alternanthera (Gomphrenoideae, Amaranthaceae): resolving a complex taxonomic history caused by different interpretations of morphological characters in a lineage with C4</sub)> and C3</sub)>-C4</sub)> intermediate species. Botanical Journal of the Linnean Society, 169(3):493-517. http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1095-8339

Sankaran T; Ramaseshiah G, 1974. Prospects for the biological control of some major aquatic weeds in South East Asia. In: South East Asian Workshop on Aquatic Weeds, Malang, 76:5.

Senna L, 2015. Alternanthera in Lista de Espécies da Flora do Brasil (Alternanthera in the list of species of the flora of Brazil). Rio de Janeiro, Brazil: Jardim Botânico do Rio de Janeiro. http://floradobrasil.jbrj.gov.br/jabot/floradobrasil/FB15403

Shaheen R; Mitra N; Mahmud R, 2006. Assessment of arsenic accumulation efficiency by selected naturally grown weeds. International Journal of Sustainable Crop Production, 1(1):24-31. http://www.gwf.org.bd/IJSCP/V1_I1_August2006/24-31.pdf

Sosa AJ; Greizerstein E; Cardo MV; Telesnick MC; Julien MH, 2008. The evolutionary history of an invasive species: alligator weed, Alternanthera philoxeroides. In: XII International Symposium on Biological Control of Weeds. 435-442.

Stevens PF, 2012. Angiosperm Phylogeny Website. http://www.mobot.org/MOBOT/research/APweb/

Sushil Kumar; Kamlesh Vishwakarma, 2005. Nutritive value of alligator weed [Alternanthera philoxeroides (Mart.) Griseb.] and its possible utility as a fodder in India. Indian Journal of Weed Science, 37(1/2):152.

Tan W Z; Li Q J; Qing L, 2002. Biological control of alligatorweed (Alternanthera philoxeroides) with a Fusarium sp., Bio Control, 47:463-479.

Thayer DD; Pfingsten IA, 2017. Alternanthera philoxeroides. Gainesville, FL, USA: USGS Nonindigenous Aquatic Species Database. https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=227

Thorpe J, 1999. Weeds of National Significance, Weeds Australia-National Weeds Strategy, www.weeds.org.au/natsig.htm.

USDA-ARS, 2016. Germplasm Resources Information Network (GRIN). National Plant Germplasm System. Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

USDA-NRCS, 2016. The PLANTS Database. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov/

Waterhouse DF, 1993. The Major Arthropod Pests and Weeds of Agriculture in Southeast Asia. ACIAR Monograph No. 21. Canberra, Australia: Australian Centre for International Agricultural Research, 141 pp.

Weber E, 2003. Invasive plant species of the world: A reference guide to environmental weeds. Wallingford, UK: CAB International, 548 pp.

Weber E; Sun ShiGuo; Li Bo, 2008. Invasive alien plants in China: diversity and ecological insights. Biological Invasions, 10(8):1411-1429. http://www.springerlink.com/content/c25570xj6u44645h/?p=3d093fec46ab4097b45b287d6033e986&pi=21

Weeds of Australia, 2016. Weeds of Australia, Biosecurity Queensland Edition. http://keyserver.lucidcentral.org/weeds/data/03030800-0b07-490a-8d04-0605030c0f01/media/Html/search.html?zoom_query=

Wu Hao; Carrillo J; Ding JianQing, 2016. Invasion by alligator weed, Alternanthera philoxeroides, is associated with decreased species diversity across the latitudinal gradient in China. Journal of Plant Ecology, 9(3):311-319. http://jpe.oxfordjournals.org/content/9/3/311.full

Wu TL, 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised):384 pp. http://www.hkflora.com/v2/flora/plant_check_list.php

Xie L; LIZ; William PG; Li D, 2000. Invasive species in China - An overview. Biodiversity and Conservation, 10(8):1317-1341.

Xu B; Weng RF; Zhang M, 1992. Chromosome numbers of Shanghai plants I. Investigatio et Studium Naturae, 12:48-65.

Yamamoto S; Kusumoto Y, 2008. An application of rural landscape information system for assessment of alien plant species in paddy landscape in Japan. Extension Bulletin - Food & Fertilizer Technology Center [Management of major emerging plant pests in agriculture in the Asian and Pacific (ASPAC) region. Paper presented at an international seminar, Taipei, Taiwan, 10-15 November 2008.], No.614:1-7.

Zeiger CF, 1967. Biological control of alligatorweed with Agasicles n. sp. in Florida. Journal of Aquatic Plant Management, 6:31-34. http://www.apms.org/japm/vol06/v6p31.pdf

Zhang T; Wang YX; Zhang ZY, 2002. Two new species of Ramularia. Mycosystema, 21(2):185-187.

Zhang Zhen; Xu Li; Zhu XiaoMin, 2010. Effect on species diversity of plant communities caused by invasion of Alternanthera philoxeroides in different habitats. Acta Prataculturae Sinica, 19(4):10-15.

Zhou Bing; Chen Jie; Ma ShengPing; Yin ShuaiWen; Wang Ning, 2016. Pathogenicity and culture condition of different isolates of Alternaria alternata on Alternanthera philoxeroides. Southwest China Journal of Agricultural Sciences, 29(2):321-326.

Zhou XiaoGang; Chen QingHua; Zhang Hui; Zheng YongSheng; Gao Han; Deng XianCai; Jiang XiaoMing; Liu Xu, 2008. Invasive alien weeds species in farmland and forest in Sichuan province. Southwest China Journal of Agricultural Sciences, 21(3):852-858.

Zhu Z; Zhou C; Yang J, 2015. Molecular phenotypes associated with anomalous stamen development in Alternanthera philoxeroides. Frontiers in Plant Science, 6:242.

Distribution References

Abud J K, 1985. Effect of herbicide mixtures in the control of Echinochloa crus-galli (L.) Beauv. and Alternanthera philoxeroides (Mart.) Griseb. in irrigated rice. (Efeitos de misturas de herbicidas no controle de Echinochloa crusgalli (L.) Beauv. e Alternanthera philoxeroides (Mart.) Griseb. em arroz irrigado.). Lavoura Arrozeira. 38 (358), 12-15.

Aston HI, 1973. Aquatic plants of Australia., Melbourne, Melbourne University Press.

Bambaradeniya CNB, 2000. Alien invasive species in Sri Lanka. In: Loris, 22 (4) 3-7.

CABI, Undated. Compendium record. Wallingford, UK: CABI

CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI

Chandra SK, 2012. Invasive Alien Plants of Indian Himalayan Region- Diversity and Implication. In: American Journal of Plant Sciences, 3 177-184.

Chong K Y, Tan H T W, Corlett R T, 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore. 273 pp. https://lkcnhm.nus.edu.sg/app/uploads/2017/04/flora_of_singapore_tc.pdf

Coulson J R, 1977. Biological control of alligatorweed, 1959-1972. A review and evaluation. In: Technical Bulletin, Agricultural Research Service, United States Department of Agriculture, [6 +] 98 pp.

DAISIE, 2016. Delivering Alien Invasive Species Inventories for Europe. http://www.europe-aliens.org/

Das S K D, Singh N P, 2006. Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae) - further extended distribution in Maharashtra. Journal of Economic and Taxonomic Botany. 30 (1), 198-200.

EPPO, 2020. EPPO Global database. In: EPPO Global database, Paris, France: EPPO.

Flora of China Editorial Committee, 2016. Flora of China. In: Flora of China. St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria. http://www.efloras.org/flora_page.aspx?flora_id=2

Funk V, Hollowell T, Berry P, Kelloff C, Alexander S N, 2007. Contributions from the United States National Herbarium, Washington, USA: Department of Systematic Biology - Botany, National Museum of Natural History, Smithsonian Institution. 55, 584 pp.

Gangstad E O, 1977. Aquatic weed problems in Puerto Rico. Journal of Aquatic Plant Management. 3-5.

Garbari F, Pedullà M L, 2001. Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae), a new species for the exotic flora of Italy. (Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae), specie nuova per la flora esotica d'Italia.). Webbia. 56 (1), 139-143.

Gunasekera L, Bonila J, 2001. Alligator weed: tasty vegetable in Australian backyards? Journal of Aquatic Plant Management. 17-20.

Guo X, Zhou X, 2005. Molecular characterization of Alternanthera yellow vein virus: a new Begomovirus species infecting Alternanthera philoxeroides. Journal of Phytopathology. 153 (11/12), 694-696. http://www.blackwell-synergy.com/servlet/useragent?func=showIssues&code=jph DOI:10.1111/j.1439-0434.2005.01039.x

Holm L, Pancho J V, Herberger J P, Plucknett D L, 1979. A geographical atlas of world weeds. New York, Chichester (), Brisbane, Toronto, UK: John Wiley and Sons. xlix + 391 pp.

Islam M M, Amin A S M R, Sarker S K, 2003. Bangladesh. In: Invasive Alien Species in South-Southeast Asia: National Reports & Directory of Resources, [ed. by Pallewatta N, Reaser J, Gutierrez A]. Cape Town, South Africa: Global Invasive Species Programme. 7-20.

Julien MH, Skarratt B, Maywald GF, 1995. Potential geographical distribution of alligator weed and its biological control by Agasicles hygrophila. In: Journal of Aquatic Plant Management, 33 55-60.

Khanna K K, 2009. Invasive alien angiosperms of Uttar Pradesh. Biological Forum. 1 (2), 34-39. http://www.researchtrend.net

Lal C, Sah M, 1990. Range extension of three exotic aquatic macrophytes in north India. Journal of the Bombay Natural History Society. 87 (3), 469.

Li LiYing, Wang Ren, Waterhouse D F, 1997. The distribution and importance of arthropod pests and weeds of agriculture and forestry plantations in southern China. In: The distribution and importance of arthropod pests and weeds of agriculture and forestry plantations in southern China. Canberra, Australia: Australian Centre for International Agricultural Research (ACIAR). x + 185 pp.

Lorenzi H, 1982. Plantas daninhas de Brasil, terrestres, aquaticas, parasitas, toxicas e medicinais. Nova Odessa, Brazil: H. Lorenzi. 425 pp.

Lou YuanLai, Shen JinLiang, Zhao YanCun, 2005. Distribution and damage of Alternanthera philoxeroides in agro-environment of Jiangsu Province. Journal of Anhui Agricultural University. 32 (4), 436-440.

Lu ZhengRong, Shen JianYing, Lu YiTong, 2005. The community succession of rice field weeds in Shanghai area and factor analysis. Acta Agriculturae Shanghai. 21 (1), 82-86.

OEPP/EPPO, 2016. Alternanthera philoxeroides (Mart.) Griseb. In: European and Mediterranean Plant Protection Organization Bulletin, 46 (1) 8-13. https://www.eppo.int/QUARANTINE/data_sheets/plants/ALRPO_ds.pdf

Pangtey Y P S, Tewari L M, Kanchan Upreti, 2012. A note on the collection of Alternanthera pheloxeroides (Mart.) Griseb. from the foothills of Kumaun (Uttarakhand). Journal of Economic and Taxonomic Botany. 36 (2), 399-400. http://www.indianperiodical.in

Patel D P, Anup Das, Rajesh Kumar, Munda G C, 2005. Comparative study of photosynthesis and associated parameters in major crops and weed species in mid hills of Meghalaya. Annals of Plant Physiology. 19 (1), 1-4.

Paudel KC, Kaini BR, 2003. Nepal: sharing experiences from agricultural and forestry sectors. In: Invasive Alien Species in South-Southeast Asia, 66-69. http://www.issg.org/pdf/publications/GISP/Resources/SEAsia-2.pdf

Ranjit J D, Suwanketnikom R, 2005. Response of weeds and yield of dry direct seeded rice to tillage and weed management. Kasetsart Journal, Natural Sciences. 39 (2), 165-173.

Rojas-Sandoval J, Acevedo-Rodríguez P, 2015. Naturalization and invasion of alien plants in Puerto Rico and the Virgin Islands. Biological Invasions. 17 (1), 149-163. http://rd.springer.com/article/10.1007/s10530-014-0712-3/fulltext.html DOI:10.1007/s10530-014-0712-3

Sankaran T, Ramaseshiah G, 1974. Prospects for the biological control of some major aquatic weeds in South East Asia. In: South East Asian Workshop on Aquatic Weeds, Malang, 76 5.

Senna L, 2015. Alternanthera in the list of species of the flora of Brazil. (Alternanthera in Lista de Espécies da Flora do Brasil)., Rio de Janeiro, Brazil: Jardim Botânico do Rio de Janeiro. http://floradobrasil.jbrj.gov.br/jabot/floradobrasil/FB15403

Shaheen R, Mitra N, Mahmud R, 2006. Assessment of arsenic accumulation efficiency by selected naturally grown weeds. International Journal of Sustainable Crop Production. 1 (1), 24-31.

Sushil Kumar, Kamlesh Vishwakarma, 2005. Nutritive value of alligator weed [Alternanthera philoxeroides (Mart.) Griseb.] and its possible utility as a fodder in India. Indian Journal of Weed Science. 37 (1/2), 152.

Thayer DD, Pfingsten IA, 2017. Alternanthera philoxeroides., Gainesville, FL, USA: USGS Nonindigenous Aquatic Species Database. https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=227

USDA-ARS, 2016. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysimple.aspx

USDA-NRCS, 2016. The PLANTS Database. Greensboro, North Carolina, USA: National Plant Data Team. https://plants.sc.egov.usda.gov

Waterhouse D F, 1993. The major arthropod pests and weeds of agriculture in Southeast Asia. Canberra, Australia: ACIAR. v + 141 pp.

Weber E, Sun ShiGuo, Li Bo, 2008. Invasive alien plants in China: diversity and ecological insights. Biological Invasions. 10 (8), 1411-1429. http://www.springerlink.com/content/c25570xj6u44645h/?p=3d093fec46ab4097b45b287d6033e986&pi=21 DOI:10.1007/s10530-008-9216-3

Wu TL, 2001. Check List of Hong Kong Plants. In: Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised), 384 pp. http://www.hkflora.com/v2/flora/plant_check_list.php

Yamamoto S, Kusumoto Y, 2008. An application of rural landscape information system for assessment of alien plant species in paddy landscape in Japan. In: Extension Bulletin - Food & Fertilizer Technology Center. [ed. by Yamamoto S, Kusumoto Y]. Taipei, Taiwan: Food and Fertilizer Technology Center for the Asian and Pacific Region. 1-7.

Zhang Tao, Wang YingXing, Zhang ZhongYi, 2002. Two new species of Ramularia. Mycosystema. 21 (2), 185-187.

Zhou XiaoGang, Chen QingHua, Zhang Hui, Zheng YongSheng, Gao Han, Deng XianCai, Jiang XiaoMing, Liu Xu, 2008. Invasive alien weeds species in farmland and forest in Sichuan province. Southwest China Journal of Agricultural Sciences. 21 (3), 852-858.

Contributors

11/11/16 Updated by:

Julissa Rojas-Sandoval, Department of Botany-Smithsonian NMNH, Washington DC, USA

Distribution Maps