'Bug warfare' to fight purple loosestrife

I first started at the Bemidji (Minn.) Pioneer as an intern in the summer of 1996. That would begin six years as a news reporter, sports reporter and copy editor for a small, six-day-per-week daily newspaper in northern Minnesota. I wrote a large range of stories from multiple beats, to features to sports, my favorite being the coverage of the Red Lake Reservation High School basketball team named the Warriors. Here is a collection of my stories from my time at the Pioneer.

July 16, 1997

By Devlyn Brooks

Staff Writer

In hopes of reducing an exotic plant that has invaded wetlands in Beltrami and other Minnesota counties, Beltrami County and the Department of Natural Resources will begin releasing European leaf-eating beetles sometime in the next week, Beltrami County Agriculture Inspector Lennard Bergstrom announced Tuesday.

Using insects to control pest plants is a process called biocontrol, and Bergstrom said they will be releasing thousands of mature leaf-eating beetles at a spot in Hagali Township, where the exotic plant purple loosestrife has begun to proliferate.

Elsewhere across the state, up to a million leaf-eating beetles soon will be unleased to attack the loosestrife, which is a "deceivingly pretty plant of European origin that muscles its way into marshes and crowds out native vegetation favored by ducks, songbirds, muskrats and other wildlife, according to a news release.

The European perennial has so far infested an estimated 38,000 acres of wetlands and lakeshore in Minnesota, and efforts to slow its spread using chemicals, burning, cutting and hand pulling have largely failed because the plant is extremely prolific and lacks natural predators in North America.

That could soon change because the Department of Natural Resources and the University of Minnesota are helping agricultural inspectors in 29 counties -- besides Beltrami -- and the Minnesota Department of Agriculture field staff raise leaf-eating beetles that prey on purple loosestrife.

Biocontrol is a common practice throughout the U.S., but this is the first time the process has been used on such a large scale for controlling purple loosestrife.

The process has been tried once in Beltrami County near Blackduck, but that was a DNR project, according to Bergstrom. This project in Hagali Township will be the first such initiative involving loosestrife by the county, which has used biocontrol for other pest plants such as leafy spurge and spotted knapweed.

The current project is the largest of about seven loosestrife sites in the county and will be the only one experimented with this year. If the project goes well, the county may expand it to some of the other sites in the future, Bergstrom said.

"Next year we'll start monitoring to see how much the (beetles) reduced the problem," he said. "It appears to have had an impact already (at the Blackduck site)."

The DNR has been studying the use of insects to control the spread of purple loosestrife since 1992, according to the news release, and it takes five to seven years before enough insects exist at a site to significantly reduce the abundance of loosestrife.

According to DNR estimates, it will take more than 20 years before enough insects are released and then reproduce in the wild to take a significant bite out of the state's purple loosestrife population.

The beetles are in no way a threat to people, Bergstrom said, because the insects will not move onto crops or native plants once they finish off their loosestrife course.

"But we'd just as soon nobody tramp around where we've released these insects," he said. "They could knock the plants over."