Pistia stratiotes (water lettuce)
Index
- Pictures
- Identity
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Description
- Distribution
- Distribution Table
- Introductions
- Risk of Introduction
- Habitat
- Habitat List
- Host Plants and Other Plants Affected
- Biology and Ecology
- Climate
- Water Tolerances
- Notes on Natural Enemies
- Pathway Causes
- Pathway Vectors
- Impact Summary
- Economic Impact
- Environmental Impact
- Threatened Species
- Risk and Impact Factors
- Uses List
- Prevention and Control
- References
- Links to Websites
- Contributors
- Distribution Maps
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Top of pagePreferred Scientific Name
- Pistia stratiotes L.
Preferred Common Name
- water lettuce
Other Scientific Names
- Apiospermun obcordatum (Schleid.) Klotzsch
- Limnonesis commutate (Schleid.) Klotzsch
- Limnonesis friedrichsthaliana Klotzsch
- Pistia aegyptiaca Schleid
- Pistia aethiopica Fenzl ex Klotszch
- Pistia africana C. Presl
- Pistia amazonica C. Presl
- Pistia asiatica Lour.
- Pistia brasiliensis Klotszch
- Pistia commutata Schleid
- Pistia crispate Blume
- Pistia cumingii Klotszch
- Pistia gardneri Klotszch
- Pistia horkeliana Miq.
- Pistia leprieuri Blume
- Pistia linguiformis Blume
- Pistia minor Blume
- Pistia natalensis Klotzsch
- Pistia obcordata Schleid
- Pistia occidentalis Blume
- Pistia schleideniana Klotzsch
- Pistia spathulata Michx.
- Pistia stratiotes var cuneata Engl.
- Pistia stratiotes var obcordata (Schleid.) Engl.
- Pistia stratiotes var spathulata (Michx.) Engl.
- Pistia texensis Klotzsch
- Pistia turpini Blume
- Pistia turpinii K. Koch
- Pistia weigeltiana C. Presl
International Common Names
- English: floating aroid; Nile cabbage; pistia; shell-flower; tropical duckweed; water bonnet; water cabbage; water fern; water lily
- Spanish: flor de tetumo; lamparilla; lechuga de agua; lechuguilla; lechuguilla de vaca; lechuguita de aqua; repollito de sapo; repollo de agua; repollo de sapo; verdolago de agua
- French: laitue d'eau; pistie; salade d’eau
Local Common Names
- Bangladesh: tokapan
- Brazil: alface-d'agua; flor-d’agua; repolho-d’agua
- Cambodia: chak thom; chal thom
- Cuba: lechuga cimarrona
- Czech Republic: babelka ezanovitá
- Dominican Republic: patico
- El Salvador: verdolaga de agua
- Germany: Wassersalat
- Hungary: kagylótutaj
- India: akasathamarai; antharathamra; boranjhanji; jalakumbi; kumbi
- Indonesia: apon-apon; apu-apu; kiapu
- Italy: pistia
- Lesser Antilles: chance; godapail
- Malaysia: kiambang
- Netherlands: slakroos
- Portugal/Azores: alface-de-água
- South Africa: waterslaai
- Thailand: chok; jawg
- Venezuela: lechuga de río; repollo de agua
- Vietnam: beo cai
EPPO code
- PIIST (Pistia stratiotes)
Summary of Invasiveness
Top of pageP. stratiotes is a perennial monocotyledonous aquatic plant present, either naturally or through human introduction, in nearly all tropical and subtropical fresh waterways. It floats on the water surface, with roots hanging below floating leaves. Its growth habit can make it a weed in waterways, where it can kill native submerged plants and reduce biodiversity. It is a common aquatic weed in the USA, and may clog waterways in warmer states such as Florida. It is listed as a noxious weed or invasive aquatic plant in some states of the USA (USDA-NRCS, 2012).
Taxonomic Tree
Top of page- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Monocotyledonae
- Order: Arales
- Family: Araceae
- Genus: Pistia
- Species: Pistia stratiotes
Notes on Taxonomy and Nomenclature
Top of pagePistia stratiotes L. is a monocotyledon, belonging to the family Araceae. The genus Pistia is monospecific with its only species P. stratiotes, described by Linnaeus in 1753.
Description
Top of pageP. stratiotes is a free-floating, stoloniferous plant with sessile leaves in rosettes. Leaves pale-green, up to 20 cm long and 10 cm wide, mostly spathulate to broadly obovate with a rounded to truncate apex, with 7-15 prominent veins radiating fanwise from the base; both surfaces , in particular the lower surface, covered by a dense mat of white woolly hairs (Cook et al., 1974; Aston, 1977; Holm et al., 1977; Sainty and Jacobs, 1981). Inflorescence axillary, solitary, ascending; spathe 1.3-1.5 cm long, convolute and adnate to the spadix below, spreading above, whitish; spadix with a single pistillate flower at base, and with 2-8 staminate flowers above, shorter than the spathe. Flowers unisexual, the perianth wanting; stamens 2; ovary 1-locular, with numerous ovules, the style slender, the stigma penicillate. Fruit thin-walled, many-seeded. Seeds cylindrical, rugulose. (Acevedo-Rodríguez and Nicolson, 2005)
The morphology of Pistia varies largely owing to the influence of environmental factors. In a survey of two populations in ponds of distinct hydrochemical characteristics, two biotypes were identified that propagate true. The biotypes were distinct regarding biomass, productivity allocation, pH of the cell saps, chlorophyll, nucleic acids, total free amino acid content of the leaves and total nitrogen, crude protein and phosphorus in whole plants (Rao and Reddy, 1984). The leaves rise into the air, but under conditions less favourable for optimal growth they may lie flat on the water.
Distribution
Top of pageAccording to Holm et al. (1977), Pistia is one of the most widely distributed hydrophytes. It has a cosmopolitan distribution throughout tropical and sub-tropical regions. In South and Central America, Africa and South-East Asia it is considered an endogenous species. While Blake (1954) and others indicate that it was introduced into Australia some 50 years ago (it was first observed during a survey in 1946/47), Gillet et al. (1988) present evidence for it being indigenous in the Northern Territory. Parsons and Cuthbertson (2001) reference a record in the Northern Territory from 1887, where a complement of organisms naturally regulates its population. Since P. stratiotes has not been recorded at nuisance levels in this area, it is highly possible that northern Australia is part of the plant’s native range.
The widespread distribution in most countries with a tropical climate may be the result of its ancient use as medicine for humans, as well as its use as fodder for cattle and pigs (Sculthorpe, 1971). The growth area of Pistia seems to be limited by low temperatures (see Small, 1933; Muenscher, 1967; Wiggins, 1980). However, scattered ephemeral populations have been reported in cold climates in the Netherlands, the Erie Canal in upstate New York and in Lake Erie in northern Ohio (Dray and Center, 2002). In these colder areas, the plant can act like an annual, re-infesting from seed each spring. Other ephemeral populations may rely on actual re-introductions. P. stratiotes is a popular aquarium plant that is often discarded in waterbodies during the summer season. In the summer of 1976 there was an excessive growth of Pistia in an area southeast of the Hague, Netherlands (see Pieterse et al., 1981). The plants died during the following winter season. In northern Africa, Pistia occurs in the Nile Delta in Egypt, but in this area, in contrast to many tropical regions, it is not a major aquatic weed (Täckholm, 1974).
Distribution Table
Top of pageThe 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.
Last updated: 12 May 2022Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
---|---|---|---|---|---|---|---|
Africa |
|||||||
Angola | Present, Widespread | ||||||
Benin | Present | Invasive | |||||
Botswana | Present | Introduced | Invasive | ||||
Burkina Faso | Present | ||||||
Burundi | Present | Introduced | Invasive | ||||
Cameroon | Present | Original citation: Hepper, 1968 | |||||
Central African Republic | Present | ||||||
Chad | Present | ||||||
Comoros | Present | ||||||
Congo, Democratic Republic of the | Present | ||||||
Côte d'Ivoire | Present | Invasive | |||||
Egypt | Present | ||||||
Equatorial Guinea | Present | ||||||
Eswatini | Present | ||||||
Ethiopia | Present | Introduced | Invasive | ||||
Gabon | Present | ||||||
Gambia | Present | ||||||
Ghana | Present, Widespread | Introduced | Invasive | Weija Lake, River Volta, Volta Lake, Tano River and Lagoon complex, Kpong Headpond, Barekese Dam, Owabi Dam, Kwanyako Dam, Mankessim Dam, Dawhenya Reservoir; other water bodies countrywide; Original citation: deGraft-Johnson and Akpabey (2015) | |||
Guinea | Present | ||||||
Guinea-Bissau | Present | ||||||
Kenya | Present | Introduced | Invasive | ||||
Lesotho | Present | ||||||
Liberia | Present | Original citation: Hepper, 1968 | |||||
Madagascar | Present, Widespread | ||||||
Malawi | Present | Introduced | Invasive | ||||
Mali | Present | ||||||
Mauritania | Present | ||||||
Mauritius | Present | ||||||
Morocco | Present | ||||||
Mozambique | Present, Widespread | ||||||
Namibia | Present | ||||||
Niger | Present | ||||||
Nigeria | Present, Widespread | ||||||
Réunion | Present | Introduced | Invasive | ||||
Rwanda | Present | ||||||
Senegal | Present, Widespread | ||||||
Seychelles | Present | Introduced | |||||
Sierra Leone | Present | Original citation: Hepper, 1968 | |||||
Somalia | Present | ||||||
South Africa | Present | Introduced | 1894 | ||||
Sudan | Present | ||||||
Tanzania | Present | Introduced | Invasive | ||||
Togo | Present | ||||||
Uganda | Present | Introduced | Invasive | ||||
Zambia | Present | Introduced | Invasive | ||||
Zimbabwe | Present | Introduced | 1948 | Invasive | |||
Asia |
|||||||
Afghanistan | Present | ||||||
Bangladesh | Present, Widespread | ||||||
Brunei | Present | Introduced | Invasive | ||||
Cambodia | Present | Introduced | Invasive | ||||
China | Present | Introduced | Invasive | ||||
-Anhui | Present | Introduced | Invasive | ||||
-Fujian | Present | Introduced | Invasive | ||||
-Guangdong | Present | Introduced | Invasive | ||||
-Guangxi | Present | Introduced | Invasive | ||||
-Hubei | Present | Introduced | Invasive | ||||
-Hunan | Present | Introduced | Invasive | ||||
-Jiangsu | Present | Introduced | Invasive | ||||
-Jiangxi | Present | Introduced | Invasive | ||||
-Shandong | Present | Introduced | Cultivated | ||||
-Sichuan | Present | Introduced | Cultivated | ||||
-Yunnan | Present | Introduced | |||||
Hong Kong | Present | ||||||
India | Present, Widespread | ||||||
-Andhra Pradesh | Present | ||||||
-Kerala | Present | ||||||
-Odisha | Present | ||||||
Indonesia | Present, Widespread | Invasive | |||||
Israel | Present, Few occurrences | ||||||
Japan | Present | ||||||
Kazakhstan | Present | Introduced | |||||
Laos | Present | ||||||
Malaysia | Present | Invasive | |||||
Myanmar | Present | ||||||
Nepal | Present | Introduced | 1952 | ||||
Pakistan | Present | ||||||
Philippines | Present | Invasive | |||||
Singapore | Present | ||||||
Sri Lanka | Present, Widespread | ||||||
Taiwan | Present | Introduced | Invasive | ||||
Thailand | Present, Widespread | Invasive | |||||
Vietnam | Present | ||||||
Europe |
|||||||
Belgium | Present | Introduced | Not established | ||||
Czechia | Present | Introduced | Not established | ||||
France | Present, Few occurrences | ||||||
Hungary | Present | Introduced | 1966 | ||||
Italy | Present | ||||||
-Sardinia | Present | ||||||
Netherlands | Present | Introduced | Not established | ||||
Norway | Present | Introduced | 1989 | ||||
Poland | Present | ||||||
Portugal | Present | Introduced | |||||
-Azores | Present | Introduced | 1999 | ||||
Romania | Present | Introduced | First reported: 1970 - 1979 | ||||
Russia | Present | ||||||
Serbia | Present | ||||||
Slovenia | Present | Introduced | 2000 | ||||
Spain | Present, Localized | ||||||
-Canary Islands | Present | Introduced | Invasive | ||||
Sweden | Present | Introduced | First reported: 2000 - 2009 | ||||
Ukraine | Present | Introduced | |||||
United Kingdom | Present | Introduced | 1983 | ||||
North America |
|||||||
Antigua and Barbuda | Present | ||||||
Belize | Present | ||||||
Canada | Present | Present based on regional distribution. | |||||
-Ontario | Present | ||||||
Costa Rica | Present | ||||||
Cuba | Present | Introduced | Invasive | ||||
Dominican Republic | Present | ||||||
El Salvador | Present | ||||||
Guadeloupe | Present | ||||||
Guatemala | Present | ||||||
Haiti | Present | ||||||
Honduras | Present | ||||||
Jamaica | Present | ||||||
Martinique | Present | ||||||
Mexico | Present | ||||||
Montserrat | Present | ||||||
Nicaragua | Present | ||||||
Panama | Present | Original citation: Fernández et al., 1993 | |||||
Puerto Rico | Present, Widespread | Invasive | Considered a weed | ||||
Saint Lucia | Present, Localized | Introduced | Ornamental in ponds, e.g. Dame Pearlette Louisy Primary School, in flood-prone Union valley | ||||
Saint Vincent and the Grenadines | Present | ||||||
Trinidad and Tobago | Present | ||||||
U.S. Virgin Islands | Present | ||||||
United States | Present | ||||||
-Alabama | Present | Introduced | Invasive | Noxious weed | |||
-Arizona | Present | ||||||
-California | Present | ||||||
-Colorado | Present | ||||||
-Delaware | Present | ||||||
-Florida | Present | Invasive | |||||
-Georgia | Present | ||||||
-Hawaii | Present, Widespread | Introduced | Invasive | Hawai’I, Kaua’I, Maui O’ahu | |||
-Kansas | Present | ||||||
-Louisiana | Present | ||||||
-Maryland | Present | ||||||
-Mississippi | Present | ||||||
-Missouri | Present | ||||||
-New Jersey | Present | ||||||
-New York | Present | ||||||
-North Carolina | Present | ||||||
-Ohio | Present | ||||||
-South Carolina | Present | ||||||
-Texas | Present | ||||||
Oceania |
|||||||
Australia | Present | Evidence exists that could be native to Northern Territory | |||||
-New South Wales | Present | ||||||
-Northern Territory | Present | ||||||
-Queensland | Present | ||||||
-Western Australia | Present | ||||||
Cook Islands | Present | Introduced | Invasive | Rarotonga Island | |||
French Polynesia | Present | Introduced | Invasive | Tahiti Island | |||
Guam | Present | Introduced | Invasive | ||||
New Caledonia | Present | Introduced | Invasive | Ile Grand Terre | |||
New Zealand | Absent, Eradicated | ||||||
Northern Mariana Islands | Present | Introduced | Rota Island | ||||
Palau | Present | Introduced | Invasive | Babledaob | |||
Papua New Guinea | Present | Eastern New Guinea Island | |||||
Solomon Islands | Present | Native | |||||
Vanuatu | Present | Invasive | |||||
South America |
|||||||
Argentina | Present | ||||||
Bolivia | Present | Original citation: Fernández et al., 1993 | |||||
Brazil | Present | ||||||
-Acre | Present | Native | |||||
-Alagoas | Present | Native | |||||
-Amapa | Present | Native | |||||
-Amazonas | Present | Native | |||||
-Bahia | Present | Native | |||||
-Ceara | Present | Native | |||||
-Espirito Santo | Present | Native | |||||
-Goias | Present | Native | |||||
-Mato Grosso | Present | Native | |||||
-Mato Grosso do Sul | Present | Native | |||||
-Minas Gerais | Present | Native | |||||
-Para | Present | Native | |||||
-Paraiba | Present | Native | |||||
-Parana | Present | Native | |||||
-Pernambuco | Present | Native | |||||
-Piaui | Present | Native | |||||
-Rio de Janeiro | Present | Native | |||||
-Rio Grande do Norte | Present | Native | |||||
-Rio Grande do Sul | Present | Native | |||||
-Santa Catarina | Present | Native | |||||
-Sao Paulo | Present | Native | |||||
-Sergipe | Present | Native | |||||
Chile | Present | Native | |||||
Colombia | Present | ||||||
Ecuador | Present | Original citation: Fernández et al., 1993 | |||||
French Guiana | Present | ||||||
Guyana | Present | Original citation: Fernández et al., 1993 | |||||
Paraguay | Present | ||||||
Peru | Present | Original citation: Fernández et al., 1993 | |||||
Suriname | Present | ||||||
Uruguay | Present | ||||||
Venezuela | Present |
Introductions
Top of pageIntroduced to | Introduced from | Year | Reason | Introduced by | Established in wild through | References | Notes | |
---|---|---|---|---|---|---|---|---|
Natural reproduction | Continuous restocking | |||||||
Florida | South America | Yes | No | Dray and Center (2002) | Experts disagree on origin and nativity |
Risk of Introduction
Top of pagePistia occurs in most tropical and sub-tropical regions. Therefore emphasis should be placed on preventing the development of dense vegetation. However, public awareness campaigns could play a role in preventing dispersion by man, for example via market gardens or the aquarium trade. It is conceivable that in certain regions this could prevent Pistia spreading from infested waterbodies to Pistia-free areas.
Habitat
Top of page
Habitat List
Top of pageCategory | Sub-Category | Habitat | Presence | Status |
---|---|---|---|---|
Freshwater | Irrigation channels | Principal habitat | Harmful (pest or invasive) | |
Freshwater | Lakes | Principal habitat | Harmful (pest or invasive) | |
Freshwater | Reservoirs | Principal habitat | Harmful (pest or invasive) | |
Freshwater | Rivers / streams | Secondary/tolerated habitat | Harmful (pest or invasive) | |
Freshwater | Ponds | Principal habitat | Harmful (pest or invasive) | |
Brackish | Estuaries | Present, no further details | Harmful (pest or invasive) | |
Brackish | Lagoons | Principal habitat | Harmful (pest or invasive) |
Host Plants and Other Plants Affected
Top of pagePlant name | Family | Context | References |
---|---|---|---|
Oryza sativa (rice) | Poaceae | Main |
Biology and Ecology
Top of pageP. stratiotes is a monoecious perennial which reproduces by means of vegetative offshoots that are connected to the mother plant by stolons, which may be 60 cm in length, as well as by the production of seeds. Holm et al. (1977) stated that flowering and fruiting vary by regions and that in most areas, with the exception of Africa, vegetative reproduction is the most important. On the other hand, Dray and Center (1989) concluded that seed germination is an important factor in the dynamics of Pistia populations in the USA. Flowering of Pistia has been induced in vitro under short days, as well as under conditions of continuous light, when the plants were cultured on nutrient media (Pieterse, 1978). Also when plants were grown in a greenhouse they flowered under both long- and short-day conditions and as a consequence it has been concluded that Pistia is a day-neutral plant (Pieterse, 1985). Seed germination was described by Datta and Biswas (1970), Pieterse et al. (1981) and Harley (1990). Datta and Biswas (1970) did not observe germination of seeds when placed on or in mud at the bottom of a beaker of water. These authors ascribed this to a low oxygen or high carbon dioxide concentration, or both, in the water. On the other hand, Pieterse et al. (1981) and Harley (1990) reported germination of Pistia seed when submerged. Holm et al. (1977) describe how seeds germinate on the surface of bottom mud and float to the surface within 5 days. Germination also occurred in the dark but period for germination was longer than under light, and the percent seed germination was lower in the dark than under constant or intermittent light. As a tropical plant Pistia does not survive freezing conditions. Though the seeds are able to survive in ice at -5°C for a few weeks, germination does not occur below 20°C. Seed dispersal has not been studied in detail. However, after shedding the seeds float for 1-2 days and are presumably transported by currents and water fowl, before they sink to the bottom of a waterbody.
Very few detailed studies have been conducted on the autecology of Pistia. Chadwick and Obeid (1966) reported that optimal growth of Pistia was obtained in water cultures at a pH of approximately 4. Such a high acidity, however, was never found in heavily infested waterbodies. It was shown by Pieterse et al. (1981) that the plant performs best in water with a pH of 7. Pistia showed particularly vigorous growth, although with a relatively small root system, in polluted water in Nigeria (Sharma, 1984).
In Lake Volta in Ghana it was observed that Pistia biomass varies in the course of the year which could be related to nutrient availability (Hall and Okali, 1974). In Florida there is a marked decline in biomass during the cold season (Dewald and Lounibos, 1990).
Climate
Top of pageClimate | 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]) | |
Cf - Warm temperate climate, wet all year | Tolerated | Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year | |
Cw - Warm temperate climate with dry winter | Tolerated | Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters) | |
Df - Continental climate, wet all year | Tolerated | Continental climate, wet all year (Warm average temp. > 10°C, coldest month < 0°C, wet all year) | |
Dw - Continental climate with dry winter | Tolerated | Continental climate with dry winter (Warm average temp. > 10°C, coldest month < 0°C, dry winters) |
Water Tolerances
Top of pageParameter | Minimum Value | Maximum Value | Typical Value | Status | Life Stage | Notes |
---|---|---|---|---|---|---|
Hardness (mg/l of Calcium Carbonate) | 5 | 20 | Optimum | Tolerates down to 1 and up to 25 mg/l | ||
Water pH (pH) | 6.5 | Optimum | ||||
Water temperature (ºC temperature) | 22 | 30 | Optimum | Tolerates down to 15 and up to 35 C |
Notes on Natural Enemies
Top of page
The Neotropics support 21 herbivorous species that exploit P. stratiotes; 5 are reported from Africa, 11 occur in Asia, and 9 insects feed on waterlettuce in Florida (Dray and Center, 2002). One of the most well studied enemies is the weevil Neohydronomus affinis. The original habitat of this promising biological control agent is South America. Neohydronomus spp. are specialist feeders on P. stratiotes throughout their natural distribution in Central and South America. Confusion over the identity of the Neohydronomus sp. introduced into Australia for biological control was clarified by O'Brien and Wibmer (1989) who recognised three species. There are a number of other P. stratiotes specialists that hold promise for use as agents of biological control. Larvae of the moth Argyractis drumalis have been found exclusively on P. stratiotes roots. The weevil Argentinorhynchus bruchi has been reported to feed, oviposit and complete larval development only on P. stratiotes. The noctuid moth Spodoptera pectinicornis was tested with 125 different plant species, but was found to complete development only on P. stratiotes and the weevil Bagous pistiae is known exclusively from P. stratiotes (see Dray and Center (2002) for detailed biocontrol information). Several other organisms cause damage to Pistia, but these generally are polyphagous.
A further range of organisms attacking P. stratiotes has been recorded from Northern Territory, Australia. These include Nymphula spp., Hydrozetes tobaicus, Nisia atrovenosa and Cercospora canescens (Gillett et al., 1988). See also Waterhouse (1993) for a listing of natural enemies of P. stratiotes.
Pathway Causes
Top of pageCause | Notes | Long Distance | Local | References |
---|---|---|---|---|
Aquaculture | Yes | Yes | Rivers (2002) | |
Escape from confinement or garden escape | Yes | Gherardi (2007); Rivers (2002) | ||
Hitchhiker | Yes | Yes | Rivers (2002) | |
Intentional release | Yes | Yes | Gherardi (2007) | |
Landscape improvement | Yes | Yes | Gherardi (2007) | |
Nursery trade | Yes | Yes | Gherardi (2007) | |
Ornamental purposes | Yes | Yes | Gherardi (2007) | |
Pet trade | Yes | Yes | Rivers (2002) |
Pathway Vectors
Top of pageVector | Notes | Long Distance | Local | References |
---|---|---|---|---|
Aquaculture stock | Yes | Yes | Gherardi (2007); Parsons and Cuthbertson (2001); Rivers (2002) | |
Floating vegetation and debris | Yes | Parsons and Cuthbertson (2001) | ||
Pets and aquarium species | Yes | Yes | Gherardi (2007) | |
Ship ballast water and sediment | Yes | Yes | Rivers (2002) | |
Water | Yes | Parsons and Cuthbertson (2001) |
Impact Summary
Top of pageCategory | Impact |
---|---|
Economic/livelihood | Positive and negative |
Environment (generally) | Negative |
Human health | Negative |
Economic Impact
Top of pageP. stratiotes can seriously interfere with paddy crops (Holm et al., 1977; Waterhouse, 1993). Although no accurate measurement is available of the loss of water needed for agriculture through transpiration from beds of P. stratiotes, losses are believed to be considerable (Holm et al., 1977).
P. stratiotes is one of the major aquatic weeds in tropical and sub-tropical regions. It rapidly forms dense mats which may completely cover the surface of the water. Consequently, such dense stands of Pistia may have serious negative effects on the multifunctional human use of waterbodies. These harmful effects include impediment of the transport of irrigation and drainage water, interference with hydro-electric schemes from artificial lakes, hindering navigation and fishing and the creation of habitats favourable for the transmittance of water-borne diseases (Mbati and Neuenschwander, 2005). In this context it should be noted that larvae of Mansonia mosquitos may directly obtain oxygen from the roots of Pistia (Gangstad and Cardarelli, 1990).
Environmental Impact
Top of pageP. stratiotes causes changes in both the physiochemical and biological characteristics of waterbodies it inhabits. Cai (2006) reports that growth of P. stratiotes causes increases in transparency, nitrate, ammonium, total nitrogen, total phosphorus and total bacteria, as well as a decrease in pH, DO, permanganate index, total plankton and plankton species diversity. The plant also influenced the size structure of planktonic communities, causing a miniaturization of plankton volume. Dray and Center (2002) review additional ecological impacts of P. stratiotes and note that they include increased rates of siltation, slowing of water velocities, degradation of fish nesting sites, increased nutrient loading, thermal stratification, increase in alkalinity and fish and macroinvertebrate mortality.
Threatened Species
Top of pageThreatened Species | Conservation Status | Where Threatened | Mechanism | References | Notes |
---|---|---|---|---|---|
Rostrhamus sociabilis plumbeus (Everglade snail kite) | USA ESA listing as endangered species | Florida | Ecosystem change / habitat alteration | US Fish and Wildlife Service (2008) |
Risk and Impact Factors
Top of page- Invasive in its native range
- Proved invasive outside its native range
- Has a broad native range
- Abundant in its native range
- Tolerant of shade
- Highly mobile locally
- Benefits from human association (i.e. it is a human commensal)
- Fast growing
- Has high reproductive potential
- Has propagules that can remain viable for more than one year
- Reproduces asexually
- Conflict
- 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 cultural/traditional practices
- Negatively impacts human health
- Negatively impacts livelihoods
- Negatively impacts aquaculture/fisheries
- Negatively impacts tourism
- Reduced amenity values
- Reduced native biodiversity
- Threat to/ loss of endangered species
- Threat to/ loss of native species
- Transportation disruption
- Competition - monopolizing resources
- Competition - shading
- Competition - smothering
- Pest and disease transmission
- Interaction with other invasive species
- Rapid growth
- Highly likely to be transported internationally accidentally
- Highly likely to be transported internationally deliberately
- Highly likely to be transported internationally illegally
- Difficult to identify/detect as a commodity contaminant
- Difficult/costly to control
Uses List
Top of pageAnimal feed, fodder, forage
- Fodder/animal feed
Environmental
- Biological control
- Revegetation
- Wildlife habitat
Fuels
- Biofuels
- Miscellaneous fuels
General
- Botanical garden/zoo
- Ornamental
- Pet/aquarium trade
- Sociocultural value
Prevention and Control
Top of pageDue 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.
Management of Pistia can be carried out by physical, chemical or biological control or by a combination of these methods (integrated control).
Physical/Mechanical Control
Physical removal of the plants can be done manually or by means of machines. Depending on the size and type of the infested waterbody different machines can be used. Weeds may be removed from irrigation and drainage canals using standard equipment such as mowing buckets attached to a tractor or a hydraulic excavator, as well as mowing launches. In general Pistia plants will grow in a mixed vegetation with rooted plants and by using these machines the total aquatic vegetation will be removed (see Wade, 1990). Special floating harvesters, which first collect the material and subsequently dump it on the shore, may be used in lakes and rivers. However, it should be taken into consideration that, in general, re-colonization of Pistia will occur. This implies that control measures should be part of a long-term maintenance programme. Cost effectiveness of the control measures will depend on the losses brought about by Pistia infestation. This will be connected with the economic importance of the waterbody as well as the indirect effect on health of the local population via water-borne diseases.
Biological Control
Neohydronomus spp. are specialist feeders on P. stratiotes throughout its natural distribution in Central and South America. Confusion over the identity of the Neohydronomus sp. introduced into Australia for biological control was clarified by O'Brien and Wibmer (1989) who recognised three species. Very promising results have been obtained with the weevil Neohydronomus affinis (Hustache) which originated in South America. DeLoach et al. (1976) reported its specificity, and in 1982 it was released in Australia and subsequently in Botswana, Zimbabwe, Benin, Senegal, South Africa, Papua New Guinea and USA (see Harley et al., 1990; ECOWAS, 1995). The insect is well established in these countries, producing relatively high levels of control.
Spodoptera pectinicornis is reported to control P. stratiotes in Thailand and has been screened and recommended for introduction into Florida, USA (Habeck and Thompson, 1994). A three-pronged attack using the related weevils Argentinorhynchus bruchi, Argentinorhynchus breyeri and Argentinorhynchus squamosus have been successful in controlling the weed’s spread in lab tests in Argentina (Anonymous, 2001). Several species of fungus have also been evaluated; Ramularia spp. (Fernandes and Barreto, 2005) and Sclerotinia sclerotiorum (Waipara et al., 2006) have shown potential for controlling P. stratiotes populations. See Waterhouse (1994) and Dray and Center (2002) for further information on biocontrol of P. stratiotes.
Chemical Control
Herbicides effective against Pistia include diquat (Thayer and Haller, 1985), a combination of diquat and triclopyr (Langeland and Smith, 1993), glyphosate (Thayer and Haller, 1985; Van et al., 1986), chlorsulfuron (Madin, 1984), terbutryn (Vermeulen et al., 1996), 2,4-D (Langeland and Smith, 1993) and endothall (Rivers, 2002).
The application of herbicides in or near waterbodies may have serious consequences for the environment. It may also endanger the health of local people if the water is used for drinking, bathing, swimming or washing. These possibilities have to be carefully assessed before the use of herbicides on any but a limited experimental basis. A special formulation of diuron known as AF101 has been recommended in Australia, as well as diquat (Parsons and Cuthbertson, 1992).
References
Top of pageAcevedo-Rodríguez P, Nicolson DH, 2005. Araceae. Contributions from the US National Herbarium, 52:44. [Monocots of Puerto Rico and the Virgin Islands.]
Acevedo-Rodríguez P, Strong MT, 2012. Catalogue of the Seed Plants of the West Indies. Smithsonian Contributions to Botany, 98:1192 pp. Washington DC, USA: Smithsonian Institution. http://botany.si.edu/Antilles/WestIndies/catalog.htm
Anonymous, 2001. Weevils wipe out waterlettuce weeds. Florida Grower, 94((10)):46
Aston HI, 1977. Aquatic plants of Australia. Melbourne, Australia: Melbourne University Press
BioNET-EAFRINET (The East African Network for Taxonomy), 2011. Keys and Fact Sheets for Invasive Plants: Pistia stratiotes (Water lettuce). http://keys.lucidcentral.org/keys/v3/eafrinet/weeds/key/weeds/Media/Html/Pistia_stratiotes_%28Water_Lettuce%29.htm
Blake ST, 1954. Botanical contributions of the northern Australian regional survey. II. Studies on miscellaneous northern Australian plants. Australian Journal of Botany, 1:99-140
Broome R, Sabir K, Carrington S, 2007. Plants of the Eastern Caribbean. Online database. Barbados: University of the West Indies. http://ecflora.cavehill.uwi.edu/index.html
Chadwick MJ, Obeid M, 1966. A comparative study of the growth of Eichhornia crassipes Solms. and Pistia stratiotes L. in water-culture. Journal of Ecology, 54:563-575
Cook CDK, Gut BJ, Rix EM, Schneller J, Seitz M, 1974. Water Plants of the World: A Manual for the Identification of the Genera of Freshwater Macrophytes. The Hague, The Netherlands: Dr W Junk
DAISIE, 2013. Delivering Alien Invasive Species Inventories for Europe. DAISIE (online). www.europe-aliens.org
Datta SC, Biswas KK, 1970. Germination pattern and seedling morphology of Pistia stratiotes L. Phyton, 27:157-161
deGraft-Johnson KAA, Akpabey FJ, 2015. Aquatic plant management in Ghana. Accra, Ghana: Council for Scientific and Industrial Research (CSIR) and Water Research Institute.
Dewald LB, Lounibos LP, 1990. Seasonal growth of Pistia stratiotes L. in South Florida. Aquatic Botany, 36:263-275
Diop O, 2006. Management of invasive aquatic weeds with emphasis on biological control in Senegal. Grahamstown, South Africa: Rhodes University
Dray FA, Center TD, 1989. Seed production by Pistia stratiotes L. (water lettuce) in the United States. Aquatic Botany, 33:155-160
ECOWAS (Economic Community of West African States), 1995. Control of Floating Weeds in the ECOWAS Member Countries. Main report. Lagos, Nigeria: ECOWAS
EPPO, 2007. EPPO Reporting Service: Inclusion of Pistia stratiotes to the EPPO Alert List. Paris, France: EPPO. http://www.eppo.int/INVASIVE_PLANTS/iap_list/Pistia_stratiotes.htm
EPPO, 2011. EPPO Reporting Service. EPPO Reporting Service. Paris, France: EPPO. http://archives.eppo.org/EPPOReporting/Reporting_Archives.htm
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
Ernest A, 2015. Diversity, distribution and control of aquatic macrophytes of southern Ghana with particular reference to the alien invasives. MPhil Thesis. Legon, Ghana: University of Ghana.
Flora of China Editorial Committee, 2012. Flora of China Web. Flora of China Web. Cambridge, Massachusetts , USA: Harvard University Herbaria. http://flora.huh.harvard.edu/china/
Forzza RC, Leitman PM, Costa AF, Carvalho Jr AA, et al. , 2012. List of species of the Flora of Brazil (Lista de espécies Flora do Brasil). Rio de Janeiro, Brazil: Rio de Janeiro Botanic Garden. http://floradobrasil.jbrj.gov.br/2012/
Gangstad EO, Cardarelli NF, 1990. The relation between aquatic weeds and public health. In: Pieterse AH, Murphy KJ, eds. Aquatic Weeds, the Ecology and Management of Nuisance Aquatic Vegetation. Oxford, UK: Oxford University Press
González-Torres LR, Rankin R, Palmarola A (eds), 2012. Invasive plants in Cuba. (Plantas Invasoras en Cuba.) Bissea: Boletin sobre Conservacion de Plantad del Jardin Botanico Nacional, 6:1-140
Govaerts R, 2013. World Checklist of Araceae. Richmond, UK: Royal Botanic Gardens, Kew. http://apps.kew.org/wcsp/
Graveson R, 2011. Plants of Saint Lucia: A Pictorial Flora of Wild and Cultivated Vascular Plants. http://www.saintlucianplants.com/index.html
Harley KLS, 1990. Production of viable seeds by water lettuce, Pistia stratiotes L., in Australia. Aquatic Botany, 36:277-279
Holm L, Pancho JV, Herberger JP, Plucknett DL, 1979. A Geographical Atlas of World Weeds. Toronto, Canada: John Wiley and Sons Inc
Hyde MA, Wursten BT, Ballings P, 2013. Flora of Zimbabwe: Species information: Pistia stratiotes. http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=112070
Krauss U, 2012. 161 Invasive Alien Species present in Saint Lucia and their current status. Caribbean Alien Invasive Species Network (CIASNET), 12 pp. http://www.ciasnet.org/wp-content/uploads/2010/08/IAS-present-in-SLU-May-2012-revision.pdf
Kurugundla CN, 2013. Two alien invasive aquatic plants of Botswana. Maun, Botswana: Water Quality and Conservation Division, Water Affairs
Mercado-Noriel LR, Mercado BT, 1978. Floral anatomy and seed morphology of water lettuce (Pistia stratiotes). Philippine Agriculturist, 61(7/8):281-290
Muenscher WC, 1967. Aquatic Plants of the United States. Ithaca, USA: Cornell University Press
Oshida T, Yanagawa H, 2002. Ecological Society of Japan. Tokyo, Japan: Chijin Shokan, 67 pp
PIER, 2003. Pistia stratiotes. Pacific Island Ecosystems at Risk
PIER, 2013. Pacific Islands Ecosystems at Risk. Honolulu, Hawaii, USA: HEAR, University of Hawaii. http://www.hear.org/pier/index.html
Pieterse AH, 1985. Pistia stratiotes. In: Halevy, AH, ed. Handbook of Flowering. Vol. IV. Boca Raton, USA: CRC Press, 94-96
Sainty GR, Jacobs SWL, 1981. Water Plants of New South Wales. Sydney, Australia: Water Resources Commission for New South Wales
Sculthorpe CD, 1971. The Biology of Aquatic Vascular Plants. London, UK: Edward Arnold Publishers
Small JK, 1933. Florida to Texas Coastal Plain. Manual of the Southeastern Flora. Lancaster, USA: The Science Press Printing Company
TSckholm V, 1974. Students' Flora of Egypt. 2nd edn. Cairo, Egypt: Cairo University
USDA-NRCS, 2012. The PLANTS Database. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov/
USDA-NRCS, 2013. The PLANTS Database. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov/
Vermeulen JB, Dreyer M, Grobler H, van Zyl K, 1996. A guide to the use of herbicides. 15th edition. National Development of Agriculture. South Africa
Wade PM, 1990. Physical control of aquatic weeds. In: Pieterse AH, Murphy KJ, eds. Aquatic Weeds. Oxford, UK: Oxford University Press, 93-135
Wiggins IL, 1980. Flora of Baja California. Stanford, USA: Stanford University Press
Distribution References
Anon, 2012. Invasive plants in Cuba. (Plantas Invasoras en Cuba). In: Bissea: Boletin sobre Conservacion de Plantad del Jardin Botanico Nacional, 6 [ed. by González-Torres LR, Rankin R, Palmarola A]. 1-140.
BioNET-EAFRINET, 2011. Invasive plants key and fact sheets., http://keys.lucidcentral.org/keys/v3/eafrinet/index.htm
CABI, Undated. Compendium record. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI
CABI, Undated b. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
DAISIE, 2013. Delivering Alien Invasive Species Inventories for Europe. http://www.europe-aliens.org/
Diop O, 2006. Management of invasive aquatic weeds with emphasis on biological control in Senegal., Grahamstown, South Africa: Rhodes University.
Ernest A, 2015. Diversity, distribution and control of aquatic macrophytes of southern Ghana with particular reference to the alien invasives. MPhil Thesis., Legon, Ghana: University of Ghana.
Flora of China Editorial Committee, 2012. Flora of China Web., Cambridge, Massachusetts, USA: Harvard University Herbaria. http://flora.huh.harvard.edu/china/
Forzza RC, Leitman PM, Costa AF, Carvalho Jr AA et al, 2012. List of species of the Flora of Brazil. (Lista de espécies Flora do Brasil)., Rio de Janeiro, Brazil: Rio de Janeiro Botanic Garden. http://floradobrasil.jbrj.gov.br/2012/
Govaerts R, 2013. World Checklist of Araceae., Richmond, UK: Royal Botanic Gardens, Kew. http://apps.kew.org/wcsp/
Holm L, Pancho JV, Herberger JP, Plucknett DL, 1979. A Geographical Atlas of World Weeds., Toronto, Canada: John Wiley and Sons Inc.
Hyde MA, Wursten BT, Ballings P, 2013. Flora of Zimbabwe: Species information: Pistia stratiotes., http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=112070
Krauss U, 2012. 161 Invasive Alien Species present in Saint Lucia and their current status. In: Caribbean Alien Invasive Species Network (CIASNET), 12 pp. http://www.ciasnet.org/wp-content/uploads/2010/08/IAS-present-in-SLU-May-2012-revision.pdf
Kurugundla CN, 2013. Two alien invasive aquatic plants of Botswana., Maun, Botswana: Water Quality and Conservation Division, Water Affairs.
Oshida T, Yanagawa H, 2002. Handbook of alien species in Japan. Tokyo, Japan: Chijin Shokan. 67 pp.
PIER, 2003. Pistia stratiotes. In: Pacific Island Ecosystems at Risk,
PIER, 2013. Pacific Islands Ecosystems at Risk., Honolulu, Hawaii, USA: HEAR, University of Hawaii. http://www.hear.org/pier/index.html
USDA-NRCS, 2012. The PLANTS Database. Greensboro, North Carolina, USA: National Plant Data Team. https://plants.sc.egov.usda.gov
USDA-NRCS, 2013. The PLANTS Database. Greensboro, North Carolina, USA: National Plant Data Team. https://plants.sc.egov.usda.gov
Links to Websites
Top of pageWebsite | URL | Comment |
---|---|---|
GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gateway | https://doi.org/10.5061/dryad.m93f6 | Data source for updated system data added to species habitat list. |
Global Invasive Species Database | http://www.issg.org/database | The GISD aims to increase awareness about invasive alien species and to facilitate effective prevention and management. It is managed by the Invasive Species Specialist Group (ISSG) of the Species Survival Commission. |
Global register of Introduced and Invasive species (GRIIS) | http://griis.org/ | Data source for updated system data added to species habitat list. |
Pacific Island Ecosystems at Risk (PIER) | http://www.hear.org/Pier/index.html | |
University of Florida and Sea Grant | http://aquat1.ifas.ufl.edu/node/634 |
Contributors
Top of page30/08/13 Updated by:
Julissa Rojas-Sandoval, Department of Botany-Smithsonian NMNH, Washington DC, USA
Pedro Acevedo-Rodríguez, Department of Botany-Smithsonian NMNH, Washington DC, USA
06/05/2009 Updated by:
Alison Mikulyuk, Wisconsin Dept of Natural Resources, Science Operations Center, 2801 Progress Rd, Madison, WI 53716, USA
Distribution Maps
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