SArestrictedClass 2 declared weed · Multiple regions
WArestrictedControl category C2 · Statewide
NTrestrictedClass B declared weed · Statewide
TASprohibitedDeclared Weed · Statewide
Salvinia molesta
African Payal (Salvinia molesta) is a free-floating aquatic fern that spreads mainly by vegetative fragments and can rapidly form dense mats over still or slow-moving water. These mats can restrict water flow, degrade water quality, reduce oxygen and light, harm aquatic habitats, block access to water for animals and people, and interfere with irrigation and recreation. It is often spread by dumping aquarium or pond contents and by movement on equipment and boats.
Distribution records are indicative. Always confirm current status with your state biosecurity authority.
Found in: still water, slow streams, ponds, dams, lagoons, calm rivers, creeks, nutrient rich water.
Control is often difficult because plants fragment easily and can rapidly re-form mats, and leaf surfaces can limit herbicide uptake. Long-term follow-up is commonly needed after initial control. Preventing spread is critical because fragments can move with water, wind, animals, and contaminated equipment, and reinfestation can occur from sheltered areas.
1
Contain floating plants with booms or nets
Install floating booms or nets to stop plant material spreading and to concentrate it for removal or treatment.
2
Remove small patches completely
Use fine-woven scoops or hand collection in small ponds and aquaria, and collect all fragments to prevent rapid regrowth.
3
Dispose of removed material securely
Seal collected plant material in plastic bags and destroy it by drying the sealed bags in the sun for a few days, or move it well away from the water’s edge to prevent reintroduction.
Registered herbicide options
Metsulfuron-MethylGroup 2 · 600 g/kg
Foliar spot spray in enclosed water bodies during non-frost periods, permit conditions apply and aquatic plants/algae toxicity is noted. Source ↗
GlyphosateGroup 9 · 360 g/L
Hand gun application using only products registered for aquatic use, permit conditions apply. Source ↗
DiquatGroup 22 · 200 g/L
Spray to wet foliage thoroughly, guidance notes not treating more than a quarter of an area at one time due to oxygen depletion risk from decaying weeds. Source ↗
FlumioxazinGroup 14 · 15 g
Applied to enclosed or still water bodies as tablets (thrown in or dissolved and injected) or as a spray solution for low-density plants, label restrictions apply. Source ↗
Orange OilGroup · 55.2 g/kg
Spray lightly on free-floating plants in non-potable, artificial and enclosed water bodies until colour changes. Source ↗
Carfentrazone-EthylGroup 14 ·
Listed as an herbicide option for spraying, results can be variable due to non-wettable upper leaf surfaces. Source ↗
Metsulfuron-MethylGroup 2 · 600 g/kg
Foliar spot spray in enclosed water bodies during non-frost periods, permit conditions apply. Source ↗
DiquatGroup 22 · 200 g/L
Spray to wet all foliage thoroughly, avoid treating more than a quarter of the area at one time due to oxygen depletion risk from decaying weeds. Source ↗
FlumioxazinGroup 14 · 15 g
Applied to enclosed or still water bodies as tablets or as dissolved/injected solution, depending on water depth and volume, label restrictions apply. Source ↗
Orange OilGroup · 55.2 g/kg
Spray lightly on free-floating plants in non-potable artificial and enclosed water bodies, just enough to change colour. Source ↗
Carfentrazone-EthylGroup 14 ·
Listed as a herbicide option for spraying, results can be variable due to non-wettable upper leaf surfaces. Source ↗
Use chemicals to the label. Always read the current APVMA-approved label before application.
Check permit conditions for your state, as some uses are limited to council or government staff.
Aquatic situations require products registered for use in or near water.
Why it matters
Impacts
Waterway blockage and access issues
Dense mats can restrict water flow, block access to water for animals and people, and interfere with irrigation equipment and pumping.
Water quality and habitat degradation
Surface mats can block light and reduce oxygen levels, causing stagnation and pollution and degrading aquatic habitats.
Infrastructure and safety hazards
Infestations can collect debris during flooding and contribute to damage such as bridge and fence collapse, and heavy mats can create entanglement hazards for children and livestock.
Mosquito breeding habitat
Mats can create favourable breeding conditions for mosquitoes.
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