Frogbit (Limnobium laevigatum)

PROHIBITED MATTER: If you see this plant report it. Call the NSW DPI Biosecurity Helpline 1800 680 244

Frogbit is a floating aquatic weed. Plants develop very quickly to form mats of runners.

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How does this weed affect you?

Frogbit is a floating freshwater plant from Central and South America. It has been kept and traded for use in fish ponds, aquariums and water features. It can rapidly invade and smother waterways and is a serious biosecurity threat to NSW. 

Plants can form into large mats of runners and adult plants can develop very quickly. Juvenile plants have a great capacity for distribution in that they are small and can be easily and quickly carried along by water currents.

Where is it found?

The first known occurences of frogbit in NSW have been found in a natural waterway in a bushland reserve, and in fish ponds on private property at Green Point, near Forster. It has also been found advertised for sale by online sellers around Sydney. These occurrances are subject to an immediate eradication response. 

How does it spread?

Frogbit spreads when plants move in water, but a common cause of spread is the dumping of illegal aquarium or pond plants in waterways. 

What does it look like?

Plants float on the water surface, and have smooth, rounded, fleshy green leaves up to 4 cm across, with sponge-like sections on their undersides. 

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Control

If found, frogbit must be reported immediately for positive identification and assistance with control and proper disposal of the plant matter. Check for plants in fish ponds, aquariums, fish tanks, water features, dams and waterways.

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

See Using herbicides for more information.


PERMIT 9907 Expires 31/03/2020
Glyphosate 360 g/L (Only products registered for aquatic use)
Rate: One part product to 50 parts water
Comments: Spot spray
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


PERMIT 9907 Expires 31/03/2020
Glyphosate 360 g/L (Only products registered for aquatic use)
Rate: One part product to 9 parts water
Comments: Splatter gun
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


Diquat 200 g/L (Reglone®)
Rate: 5 L of product per megalitre of water
Comments: Apply by injection below the surface or as a surface spray.
Withholding period: 1 day in pasture, 10 days in treated water.
Herbicide group: L, Inhibitors of photosynthesis at photosystem I (PSI inhibitors)
Resistance risk: Moderate


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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 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.
All of NSW Prohibited Matter
A person who deals with prohibited matter or a carrier of prohibited matter is guilty of an offence. A person who becomes aware of or suspects the presence of prohibited matter must immediately notify the Department of Primary Industries
All species of Limnobium are Prohibited Matter

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For technical advice and assistance with identification please contact your local council weeds officer.
For further information call the NSW DPI Biosecurity Helpline on 1800 680 244 or send an email to weeds@dpi.nsw.gov.au

Reviewed 2018