Cason & Associates, LLC

Accredited lake management professionals, providing professional resources for managing, building and restoring lakes, ponds, rivers and wetlands.

Serving Wisconsin, Upper Peninsula of Michigan and Northwestern Illinois.

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Eurasian Watermilfoil Control Programs

lake1What is it?

Eurasian watermilfoil (Myriophyllum spicatum) is an exotic submergent aquatic plant originally from Europe and Asia. It is an aggressive, rapidly growing plant that displaces native plants and clogs waterways. Eurasian watermilfoil poses serious threats to the ecological health and recreational value of lakes. Found in scattered areas throughout the U.S., the plant has recently invaded lakes in Wisconsin.

Threats to recreation:

Eurasian watermilfoil can grow to the surface in waters as deep as 20 feet. When mature, the plant forms a dense surface mat or canopy that may be thick enough for birds to walk on. Boating, swimming and fishing activities are often inhibited by this mass of vegetation.

Threats to lake ecology:

Due to its aggressive early-season growth, Eurasian watermilfoil displaces nearly all native submergent plant species. Studies have shown that this reduced plant diversity results in a reduced diversity of invertebrates and other organisms that fish feed upon.

Threats to fisheries:

The extremely dense plant beds formed by Eurasian watermilfoil provide excellent cover for juvenile panfish – to the point where they are virtually inaccessible to predator fish. This typically results in overabundant, stunted populations of panfish. Correspondingly, growth rates of predator fish such as largemouth bass and northern pike are reduced.

Water quality impacts:

Stagnant, oxygen-depleted conditions are often found in association with dense beds of Eurasian watermilfoil. The sudden nutrient release caused by the late-season die back of massive plant beds may also cause nuisance algae blooms.

Economic impacts:

Millions of dollars are spent annually to control Eurasian watermilfoil. Left unchecked however, the loss of real estate values and the losses to tourism and recreation-based industries would be far greater.


lake2Our Biologists have helped more than 50 lake management organizations throughout Wisconsin and Upper Michigan to implement effective Eurasian watermilfoil management programs. We believe that a successful milfoil management program requires proper planning. Our first step is to collect baseline data on the aquatic plant community. We plot, measure and map milfoil beds using GPS technology. Next, we identify lake-specific concerns and discuss management alternatives with the lake group. Survey data and public input is then incorporated into a long-term management plan.

While many different tools have been employed for controlling Eurasian watermilfoil, the most successful strategy for providing long-term control has proven to be treatment with granular 2,4-D herbicide. 2,4-D treatments are economical, effective and have few negative environmental impacts. In order to be effective in providing long-term control, 2,4-D herbicide must be thoroughly and accurately applied to all Eurasian watermilfoil in the lake. Otherwise untreated milfoil will quickly repopulate the lake. This is why Cason & Associates’ certified and insured herbicide applicators work diligently to ensure that all Eurasian watermilfoil is identified and treated.

While there are no magic solutions to Eurasian watermilfoil problems, long-term success can be achieved once milfoil has been effectively controlled through regular lake monitoring and timely spot treatment of any milfoil regrowth. Give us a call today to discuss a Eurasian watermilfoil monitoring or control program for your lake!