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Salvinia
- Salvinia roots
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- Salvinia infestation
General information
Of the several species of salvinia that occur naturally in America, Europe and Asia, only one - Salvinia molesta, a native of Brazil - has become established in Queensland.
Salvinia is mainly spread by people who empty aquariums and ponds into waterways.
Salvinia molesta is a Class 2 declared pest plant under Queensland legislation and a Weed of National Significance (WONS). All other species of Salvinia not yet found in Queensland are declared Class 1 pest plants.
| Scientific name |
Salvinia spp. |
| Impacts |
- forms thick mats that can completely cover water storage areas in a short time
- endangers children and livestock who can become entangled in heavy infestations
- creates a haven for mosquitoes
- prevents access by stock to drinking water
- reduces water flow to irrigation equipment, increasing pumping times and costs
- builds up and collects debris during flooding, causing bridges and fences to collapse
- causes a fourfold increase in water loss through evaporation
- degrades water quality
- destroys wildlife habitats
- interferes with recreational activities such as boating, fishing and swimming
- spoils the natural beauty of open water, such as dams and lakes
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| Description |
- a free-floating aquatic fern
- small spongy green leaves are positioned in pairs along a common stem
- leaf surfaces are covered with long, stiff, water-repellent hairs
- as the plant matures, leaves become thick and fold at the mid-rib
- young leaves are oval, about 12 mm across and lie flat on the water, often resembling duckweed
- roots trail from each pair of young leaves
- as the plant matures, the long roots resemble wet hair
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| Habitat/Distribution/Life cycle |
- found in isolated water bodies from North Queensland to the New South Wales border, and west to Mt Isa
- prefers slowly-moving streams or still water ponds with high nutrient levels and water temperatures of 20oC to 30oC
- believed to be a sterile hybrid
- does not produce flowers, reproducing by vegetative means
- produces little growth in winter
- under optimal conditions can double in volume every 2-3 days
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| Control |
- treat infestations when small
- remove small areas by hand or machine
- release biological control agent, Salvinia weevil
- apply herbicides strictly in accordance with label directions
- see the salvinia fact sheet for further information, including registered herbicides and application rates
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| Declaration details |
- Salvinia molesta is a declared Class 2 species under the Land Protection (Pest and Stock Route Management) Act 2002
- all other Salvinia spp. not yet found in Queensland are Class 1
- control of declared pests is required by landholders
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| Further information |
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Page maintained by Sonia Jordan
Last reviewed 14 September 2011
