sealPurdue News

March 10, 2000

4-H'ers fight plant invader, learn about exotic species

WEST LAFAYETTE, Ind. – Purdue University specialists have teamed up with 4-H'ers across Indiana to fight purple loosestrife, a European plant invader that plagues Midwestern marshes and lowlands.

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"When purple loosestrife comes in, it takes over," said Pat Charlebois of Illinois-Indiana Sea Grant. "It pushes everything else out. And animals don't use it." The plant's seeds are even too small for birds to eat.

How did this exotic plant get here?

Back in the 1800s, immigrants coming to New England so admired loosestrife's flowers that they brought it with them and planted it in gardens. From their flowerbeds, purple loosestrife spread through most of the United States. It made itself so at home in the Midwest and Northeast that some people there call it the "purple plague." The insects that control it in Europe don't exist in the United States.

To help bring the invader under control, Charlebois and Natalie Carroll, the state environmental 4-H specialist, are teaching volunteer 4-H leaders to raise loosestrife-eating Galerucella beetles this spring. The beetle's entire life cycle depends on purple loosestrife, and the beetles don't harm any other plants or wildlife, according to staff at the Indiana Department of Natural Resources. After adult beetles lay eggs on the plant, larvae hatch out and start feeding on loosestrifes' growing tips. As they eat and grow, larvae reduce the leaves to skeletons. Even after they pupate and emerge as adults, the beetles keep eating loosestrife leaves.

A few years ago, staff from Indiana's DNR released beetles in lowlands in the northern part of the state. Carroll's efforts with 4-H leaders and students will extend DNR's program.

"They are building on the DNR project, which is a very good thing," said Bob Waltz, director of DNR's Division of Entomology and Plant Pathology. "We will get effective control earlier in the areas where they release beetles."

This year, Carroll and Charlebois are targeting 4-H leaders in northern Indiana. The leaders, in turn, will teach 4-H members about the purple loosestrife problem. Then they'll show 4-H'ers how to release beetles in local wetlands and lowlands infested with the plant. After they let the beetles go, the 4-H'ers will track the impact that beetles have on loosestrife. They'll estimate the amount of insect damage, count beetles, keep the data in notebooks, and graph the results. In essence, they'll be doing scientific research.

"This new program brings together adults and youths to help solve a local environmental problem," Carroll said. "It also will help 4-H'ers learn more about the impact of exotic species."

Learning about this plant invader will help people understand other exotic species problems we face, Carroll said. Purple loosestrife is just one of many exotic invaders that environmental groups, industries and farmers fight.

"In the Great Lakes alone we have more than 140 exotic species," said Charlebois, who monitors the spread of non-native species in Midwestern lakes and streams. "Most of them don't cause much harm, but just one exotic can have a whole suite of impacts on native species."

Approximately one out of seven exotics causes trouble by eating, crowding out or sickening native plants and animals. Exotics have even wiped out some native species. Plants like purple loosestrife are some of the worst invaders along the Great Lakes, Charlebois said.

To protect native wildlife that's left, we need to control already established invaders and keep out new ones, Charlebois said. An endangered songbird, flower, clam or toad may contain the key to curing a disease. Or it may be the anchoring thread in an ecological web that keeps the air or water clean.

Exotics also cost us money. A 1993 report from the Congressional Office of Technology Assessment said that introduced species in the United States cost taxpayers from hundreds of millions to billions of dollars annually.

4-H leaders who want to be part of the purple loosestrife control project can contact Carroll at (765) 494-8433;

Sources: Natalie Carroll, (765) 494-8433;

Pat Charlebois, (847) 872-0140;

Writer: Rebecca J. Goetz, (765) 494-0461,

Purdue News Service: (765) 494-2096;

Related Web sites:
Indiana DNR Purple Loosestrife
Cooperative Agriculture Pest Survey & NAPIS' page on purple loosestrife
U.S. Global Change Information Office: Impacts of Introduced Species in the United States
The Nature Conservancy: Wildland Invasive Species Program

Early settlers in the United States planted purple loosestrife for its flowers, but the plant spread to become a "purple plague" in some lowlands, such as this one near Lohansport, Ind. The exotic plant, which makes poor wildlife habitat, pushes out native vegetation. (Purdue Agricultural Communication Service photo by Carole Lembi)
A publication-quality photograph is available at the News Service Web site and at the ftp site. Photo ID: carroll.loosestrife

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