Eurasian water milfoil is an underwater weed with olive-green feathery leaves. It can quickly take over waterways.
Eurasian water milfoil grows quickly and:
Eurasian water milfoil is a perennial aquatic weed that is mostly submerged except when flowering.
Each leaf is divided into 5–25 pairs (usually more than 12) of leaflets.
Male flowers are:
Female flowers:
Eurasian water milfoil does not currently grow in Australia. If introduced, it could become a major weed of dams, lakes and reservoirs.
Eurasian water milfoil is native to Europe, Asia and northern Africa.
It is now naturalised and a major weed of lakes and reservoirs in Canada and the USA.
Eurasian water milfoil:
This weed is mostly spread by plant fragments. During the growing season plants automatically break into fragments, often developing roots before they separate from the parent plant. Water movement and human activities may also cause the plants to break. Fragments are spread over long distances by water currents. They are mainly dispersed between different water bodies by boating and fishing activities.
Eurasian water milfoil may die back to the base during winter and reshoots in spring.
By Seed
Eurasian water milfoil produces up to 112 seeds per stalk and seeds may stay dormant for many years. Seeds usually need at least 15°C for germination. Overseas germination has not been observed often. Seeds are spread by moving water and by water birds.
Aiken S.G., Newroth P.R. and Wile I. (1979) The biology of Canadian weeds, 34. Myriophyllum spicatum L., Canadian Journal of Plant Science, 59: 201–215.
Grace, J. B., & Wetzel, R. G. (1978). The production biology of Eurasian watermilfoil (Myriophyllum spicatum L.): a review. J. Aquat. Plant Manage, 16(1), 1-11.
Hartleb, C. F., Madsen, J. D., & Boylen, C. W. (1993). Environmental factors affecting seed germination in Myriophyllum spicatum L. Aquatic Botany, 45(1), 15-25.
Hosking J.R., Sainty G., Jacobs S., and Dellow J (in prep.), The Australian WEEDbook.
Please do not attempt to treat or dispose of this weed yourself. Report this plant if you see it anywhere in NSW by calling the helpline listed at the top of this page immediately.
NSW DPI will lead an initial response for the treatment and disposal of the plant to stop it from spreading
Control of Eurasian water milfoil is difficult. Mechanical harvesting can lead to rapid reinfestation due to the plant being fragmented.
See Using herbicides for more information.
Dichlobenil 40 g/kg
(Casoron 4G Herbicide)
Rate: 2.9 to 3.9 kg per 10m2
Comments: Exposed soil. DO NOT apply to water which will be used for crop irrigation, for livestock watering, or for human consumption.
Withholding period: Do not graze livestock on treated areas.
Herbicide group: 29 (previously group O), Inhibition of cellulose biosynthesis
Resistance risk: Moderate
Dichlobenil 40 g/kg
(Casoron 4G Herbicide)
Rate: 287 to 388 kg per ha or 2.87 to 3.88 kg per 100m2
Comments: Water less than 1m deep. Apply when weeds are dormant. DO NOT apply to water which will be used for crop irrigation, for livestock watering, or for human consumption.
Withholding period: Do not graze livestock on treated areas.
Herbicide group: 29 (previously group O), Inhibition of cellulose biosynthesis
Resistance risk: Moderate
Dichlobenil 40 g/kg
(Casoron 4G Herbicide)
Rate: 388 to 574 kg per ha or 3.88 to 5.74 kg per 100m2
Comments: Water more than 1 m deep. Apply when weeds are dormant. DO NOT apply to water which will be used for crop irrigation, for livestock watering, or for human consumption.
Withholding period: Do not graze livestock on treated areas.
Herbicide group: 29 (previously group O), Inhibition of cellulose biosynthesis
Resistance risk: Moderate
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. |
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 |
Reviewed 2020