Duckweed (Lemna disperma)
Duckweed is a small floating aquatic plant. It is a native plant that can form dense mats and block pumps.
This is a native plant. Check native vegetation requirements before undertaking control
This plant is a water weed
Profile
How does this weed affect you?
Duckweed can form a dense green mat on the surface of a slow-moving or stationary water body in nurtrient rich conditions. They are an important food source for birds and aquatic animals.
What does it look like?
Duckweeds are tiny, free-floating plants that are native to Australia. They include the smallest flowering plants on Earth. Duckweeds have tiny, white, barely visible flowers, and spread mainly by fragments.
More information
Control
Herbicide options
WARNING - ALWAYS READ THE LABEL
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au
See Using herbicides for more information.
Diquat 200 g/L
(Reglone®)
Rate: 5.0–10.0 L/ha
Comments: Spray to thoroughly wet all the foliage. Use the higher rate for heavy infestations or for deep dirty water. Do not treat more than 1/4 of the area at once to avoid deoxygenation of water.
Withholding period: Do not use treated water for human consumption, livestock watering or irrigation purposes for 10 days after application. Do not graze or cut sprayed vegetation for stock food for 1 day after application. See label for harvest withholding periods.
Herbicide group: 22 (previously group L), Inhibition of photosynthesis at photosystem I via electron diversion (PSI electron diversion)
Resistance risk: Moderate
Diquat 200 g/L
(Reglone®)
Rate: 400 mL/ha plus 150 mL AGRAL®(wetting agent) per 100 L water
Comments: Small areas: Spray to wet weeds thoroughly. About 1 mL of product should be sufficient to treat about 1 m2.
Withholding period: Do not use treated water for human consumption, livestock watering or irrigation purposes for 10 days after application. Do not graze or cut sprayed vegetation for stock food for 1 day after application. See label for harvest withholding periods.
Herbicide group: 22 (previously group L), Inhibition of photosynthesis at photosystem I via electron diversion (PSI electron diversion)
Resistance risk: Moderate
Orange oil 55.2 g/kg
(Water Clear®)
Rate: 1 .0 L per 100 L of water
Comments: Spray on to free-floating plants.
Withholding period: Nil.
Herbicide group: n/a
Resistance risk: n/a
Biosecurity duty
The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.
| Area | Duty |
|---|---|
| All of NSW | General Biosecurity Duty All pest plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable. |
For technical advice and assistance with identification please contact your local council weeds officer.
Reviewed 2024
