Invasive Eurasian water milfoil is flourishing in Wisconsin’s lakes, sometimes outcompeting native plants and creating floating mats that cause problems for people, boats and property values. But new research shows that the benefits of using one type of historical lake-wide herbicide treatment may be outweighed by the costs to native aquatic plants.
Lake management teams often try to tackle their milfoil problems with chemicals, which reduce the size of the milfoil population but can have off-target effects. In most lakes, lake-wide herbicide treatments are associated with more native plant declines than the milfoil, according to the study, published recently in the journal Facets.
For many lakes, it’s likely they may not have to use a lake-wide herbicide treatment on milfoil until native plant species are clearly suffering. For other lakes, a control regime not involving herbicides may work instead.