Purple Loosestrife (PL) is a non-native plant that has become a serous ecological concern. It displaces other native wetland plants and can become the dominant plant, reducing species diversity and in turn changing the ecosystem of a wetland. In Wisconsin alone, an estimated 40,000 acres are plagued by this unwelcome guest. A single PL plant can produce 1-2 million seeds and will also invade drier, non-wetland sites.

An erect, perennial herb in the Loosestrife family, purple Loosestrife (Lythrum salicaria) was introduced to the United States and Canada from Europe in the early 1800s in ship ballast and as a medicinal herb and ornamental plant.

Loosestrife plants grow from four to ten feet high, depending upon conditions, and produce a showy display of magenta-colored flower spikes throughout much of the summer. The PL flowering season, generally from June to September, allows it to produce vast quantities of seed. Flowers have five to seven petals that are arranged in long racemes, and mature plants can have from 30 to 50 woody stems arising from a single rootstock.

Several sites in Vernon County are already infested with this plant. Large numbers of this plant are located in the Bad Axe Watershed near Chaseburg and north of  Hillsboro. Methods to control the spread of this perennial include digging and hand pulling, cutting chemical control and biological control. Biologic control, which is using a living organism to control a pest, has become a popular method for controlling PL, particularly in areas of severe infestation where manual and chemical control efforts are ineffective and may in fact contribute to the problem. A leaf-eating beetle, Gallerucella spp., has been found to be a most effective biological method for combating PL. 

The Vernon County Land and Water Conservation Department has received several grants from the U.S. Fish and Wildlife Service for materials to develop artificial rearing sites to raise beetles. Working with High School and Junior High Students the beetles are raised on purple Loosestrife plants in plastic swimming pools. One beetle is capable of hatching over one hundred new beetles. Each artificial rearing pond has 100 beetles so potential over 10,000 new beetles could be raised to be released in wetlands with Purple Loosestrife is present.

The hope is that the beetles will develop their own population in the wild and will continue to feed on the purple Loosestrife plants until they are reduced in numbers that native plants will come back. So far the project has been very successful on a couple of wetlands in the Bad Axe watershed and at the entrance to Hillsboro Lake.