The beetle battle against purple loosetrife

Bob Stegmier shows how easy it is to fight a harmful invasive plant by transplanting beetles.

Bob Stegmier shows how easy it is to fight a harmful invasive plant by transplanting beetles.

An imported beetle that eats an invasive plant is being used to restore native wetland species such as cattails. Jim Biener and Bob Stegmier of the Dwight Lydell Chapter of the Izaak Walton League of America are looking for some friends with good eyesight and steady hands to again collect these beetles and spread them into loosestrife infested wetlands. Jim, 361-1353, coordinates the efforts in the townships of Cannon and Grattan. Bob Stegmier, 866-4769, coordinates the efforts for the Ike’s and the Rouge River Watershed Council in the Rogue River watershed.


Beetles feed on Purple Loosestrife.
Beetles feed on Purple Loosestrife.

Purple Loosestrife is an unwanted “beauty” in our midst. This statement so definitely describes the non-native Purple Loosestrife wetland plant in North America. From a good beginning in 2007 volunteers will again be in the wetlands colonized with the Gallerucella calmariensis beetle collecting the beetle as they emerge from the soil and beginning their spring eating and mating process. The aim of these volunteers is to collect beetles before they lay their eggs and transplant them into areas with P.L. so the eggs will be hatched in the new area. That way two beetles transplanted produces 500 new larva to eat loosestrife blossoms and seeds making our effort very effective.


The Rogue River Watershed Council (RRWC) with the guidance of Dwight Lydell Chapter of the Izaak Walton League will continue to collect and spread the Purple Loosestrife eating Gallerucella calmariensis beetle in the Rogue River watershed. This is a volunteer effort to control the spread of the non-native Purple Loosestrife wetland plant. Good progress is being steadily made from the south of the watershed northward. While this plant is pretty with its tall slender purple spikes it is still very much a plant that if left uncontrolled would significantly alter the native plant structure of our wetlands. Native Michigan wetland species find very little value in the plant. The beauty is short lived lasting only a few weeks in July before the blossom and stalk structure dies and turns brown. The damage continues all growing season long as the plant crowds out native plants. The result is that Michigan native wetlands species loose their “preferred” living habitat. 

Volunteers are needed and folks throughout the watershed are invited to volunteer to help in this important environmental control effort. Every year from year to year we are making good progress in controlling the affects of Purple Loosestrife.
Led by Jim Biener and Bob Stegmier of the Izaak Walton League of America, these volunteer groups will be collecting Gallerucella calmariensis beetles in areas where the beetles have known healthy populations. The emergence of the beetles is very sensitive to weather conditions so we need to be flexible. Collect the beetles and deliver them to pre-identified areas that currently do not have the beneficial bugs.

The Gallerucella calmariensis has been shown as an effective method for lowering Purple Loosestrife populations. The beetles feed exclusively on Purple Loosestrife leaves and growing tips, stunting the plants and reducing seeds without doing any damage to any other plant. Every year there are folks that express concern that the beetles will take their eating efforts to other plants. This is not a concern because before the first beetles were released this was completely studied to total satisfaction by Michigan State University. Over time the Purple Loosestrife is brought under control and the native species return.

The beetles will be collected where they are known to have healthy populations.

Purple Loosestrife (Lythrum salicaria) is a beautiful, extremely hardy but aggressive perennial wetland invader which can quickly take over a wetland area by choking out native species of plants and wildlife and effectively destroying the native wetland habitat.
In Michigan, hundreds of species of plants, birds, mammals, reptiles, insects, fish and amphibians rely on healthy, native wetland habitat for their survival. We are currently losing wetland habitats at an alarming rate due to the spread of this invasive species.
Purple Loosestrife is a tall (five to seven feet), broad, dark green clump of stems with very showy reddish-purple flowers from July through August. It grows along rivers, lakes, streams, in wetlands and drainage ditches and along roadsides.
It is estimated that just one mature plant can produce in excess of 2.7 million seeds in one season. The seeds are very tiny and are spread by wind, water, the fur and feathers of animals, or in mud attached to animals or humans and carried from place to place.
In 1995, Michigan passed an amendment to Act 189 of the Public Acts of 1931, which forbids the sale and distribution of Purple Loosestrife. It is now against the law to sell, distribute or propagate this plant in the state.
Purple Loosestrife should never be cut and used in a flower arrangement or transplanted to a garden, roadside or landscape area. It will quickly overtake a garden and become a nuisance for the gardener and will soon disperse and spread to other areas and overtake and kill out the native species.
Where Purple Loosestrife is established, the best method for control is to cut the flower heads while the bloom is new and the flower petals have not yet begun to fall. The plants should be watched closely for several months and any new flower spikes removed.
This method of control has successfully re-established several wetland areas in the Rockford area. If there is a new, young patch of growth, pulling the whole plant, roots and all, again prior to seeding, is a very good method of control. Cuttings and plants should be disposed of in such a way that new plants cannot sprout from the cuttings and seeds cannot be dispersed. Composting is not recommended as the seeds may remain viable even after composting.
Michigan State University and Michigan Sea Grant created the Purple Loosestrife Project in 1996 which uses Gallerucella calmariensis as a biological control agent for Purple Loosestrife. The method has been successfully introduced into hundreds of infested sites with excellent success. The beetles feed exclusively on Purple Loosestrife leaves and growing tips, stunting the plants and reducing seed production. Over time the Purple Loosestrife is brought under control and the native species return. This method also has been used in the City of Rockford along the Rogue River and appears to be succeeding.

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