About Eurasian Watermilfoil
To prevent this unwanted invader from spreading in the province, Ontario has regulated Eurasian water-milfoil as restricted under the Invasive Species Act, 2015.
Background
Eurasian water-milfoil is an invasive aquatic plant native to Europe, Asia, and northern Africa. Introduced to North America in the 19th century, it is now one of the most widely distributed invasive aquatic plants on the continent. It is suspected to have been introduced via ballast water, but was then moved around within the province through recreational watercrafts and natural expansion.
Eurasian water-milfoil prefers shallow water 1-3 m (3.3 – 9.8 ft) deep, but can root in up to 10 m (32.8 ft) of water. Being a fast-growing perennial, it forms dense underwater mats that shade out other aquatic plants. When large stands begin to die off in the fall, the decaying plants can reduce oxygen levels in the water, potentially affecting the fish communities.
The plant can hybridize with Ontario's native milfoil, northern water milfoil (Myriophyllum sibericum), creating a more aggressive form of the invasive species. Because tiny plant pieces can develop into new plants, Eurasian water-milfoil is easily spread when water currents, boat propellers, trailers, or fishing gear carry plant fragments to new areas.
Best Management Practices for Managing EWM
These Best Management Practices (BMPs) provide guidance for managing invasive Eurasian water-milfoil (Myriophyllum spicatum) in Ontario. Funding and leadership for the production of this document was provided by Environment and Climate Change Canada, Canadian Wildlife Service – Ontario (CWS-ON). These BMPs were developed by the Ontario Invasive Plant Council (OIPC) and its partners to facilitate invasive plant control initiatives by individuals and organizations concerned with the protection of biodiversity, agricultural lands, infrastructure, crops and species at risk in Ontario.
The intent of this document is to relay specific information relating to aquatic invasive plant control practices that have been recommended by leading professionals across Ontario. This document contains the most up-to-date, effective, and environmentally safe control practices known from research and experience. It complies with current provincial and federal legislation regarding pesticide usage, habitat disturbance and species at risk protection. It is subject to change as legislation is updated or new research findings emerge. The information provided in this BMP is not to be considered legal advice. The timing windows suggested will differ throughout Ontario and by management activity and should be tailored to your region. Interested parties are advised to refer to the applicable legislation to address specific circumstances. Check the website of the OIPC for updates.
