Eurasian watermilfoil has been around North America since the 1940s and since then, this invasive species has infiltrated over 300 lakes in Minnesota.
“Recreational users, boaters, it’s really hard to paddle through, swim through, boat through,” said Dr. Ray Newman. “It washes up on shore and causes all sorts of problems. Ecological problems, it comes up and forms a canopy so you’ll see those mats with little flower spikes sticking out, and it shades out the native plants and the native plants have a hard time getting established.”
New research at the University of Minnesota is testing a native milfoil weevil -- basically a very small beetle -- to see how it eats the milfoil. Their current study involves these enclosures on Cedar Lake.
“We put them around milfoil beds, and we’re going to stock sunfish into several of those enclosures to try to see what the effect of sunfish are on herbivores who would feed on the milfoil,” explained Dr. Newman.
For the sunfish, the weevil can be a reliable food source. Using these three enclosures, they’re going to see if having more sunfish means fewer weevils and more milfoil. Their tests will continue throughout the summer.