Purple Loosestrife

Purple Loosestrife Biological Control for Hog Island, Superior Bay, Superior, Wisconsin.

The UWS- Lake Superior Research Institute, in collaboration with Douglas County, is launching a habitat restoration project on Hog Island and Allouez Bay near Superior. A key phase of our project is to control invasive plant species, including purple loosestrife. Purple loosestrife is an aggressive perennial plant of European origin found throughout Canada and the United States. Purple loosestrife is a serious concern because it displaces native wetland plants and can become the dominant plant, thereby reducing species diversity and changing the ecosystem of a wetland.

Two species of beetles in the genus Galerucella are used for bio-control of the exotic wetland weed purple loosestrife (Lythrum salicaria). The beetles and plants were reared in early April at the greenhouse in McCaskill Hall on the UWS campus. Ten adult beetles were placed on 50 plants. The beetles soon layed their eggs and upon release in early-mid July more than 2000 beetles were present on each plant. An on-going monitoring project began during the fall of 2010. It typically takes from 1-3 years for noticeable effects to take place.