MN Impact: Hybrid Watermilfoil is a New Threat to MN Lakes

September 18, 2017

Issue

Invasive aquatic plants are difficult to control and restoring native habitats after controlling an invasive pest is even more difficult. More information is needed to develop effective control and, ultimately, restoration efforts.

What has been done

Researchers at the University's Aquatic Invasive Species Research Center setout to discover the status of hybrid watermilfoil--a cross between the invasive Eurasian watermilfoil and Minnesota's native northern watermilfoil--in Lake Minnetonka and how it is or is not affected by herbicide applications being used to control Eurasian watermilfoil.

Results

Using cutting edge genetic screening techniques, researchers discovered that hydrid watermilfoil is actually denser in areas treated with herbicides. This finding highlights the need to customize management techniques for invasive species to the plants' specific genetic makeup. And in the case of watermilfoil, the study also revealed the species is more genetically diverse than previously thought. This pilot study has already led to plans for a larger study and will inform Extension outreach regarding management techniques for controlling watermilfoil in Minnesota's waters.