EDITORS: Photos are available on request.

ANN ARBOR—Many Michigan roadside ditches and wetlands have become especially colorful during the past few weeks because the invasive plant purple loosestrife is blooming.

Purple loosestrife (Lythrum salicaria) is problematic because it displaces native wetland plants and degrades wetland habitat for fish and wildlife. The colorful plant has become so prevalent because it has encountered few predators in most places and each plant can produce more than 2 million seeds per year.

The aggressive growth of purple loosestrife in wetland ecosystems (bogs, swamps, riverways, and ditches) has captured the concern of state and federal agencies, scientists, environmentalists, hunters and anglers across the United States. Control of purple loosestrife has included hand pulling, burning, chemical applications and, most recently, using natural enemies in a biological assault.

However, this year the pesky plant is not so prevalent in some places as it has been, according to Michigan Sea Grant researchers. After introducing leaf-feeding beetles Galerucella pusilla and G. calmariensis, resource managers and volunteers, including students and their teachers, have seen dramatic results in many infested wetlands.

The Michigan Department of Natural Resources first released the U.S. government approved beetles in the Saginaw Bay watershed in 1994. By 2000, the stands of purple loosestrife there had dwindled to a fraction of the peak infestation. Monitoring of a beetle-treated wetland at Pointe Mouillee in 2000 showed that purple loosestrife was completely absent from seven of the nine areas where it had occurred in 1997. Approximately 200 sites statewide have been inoculated with the beetles.

The Purple Loosestrife Project, coordinated by Michigan Sea Grant Extension Associate Mike Klepinger and Michigan State University Extension entomologist Doug Landis, has trained 150 teacher volunteers to use the beetles. Klepinger and Landis have established a network of 24 Cooperative Biological Control centers, produced instructional and educational materials and maintain a Web site.

Project leaders and participants are very optimistic about the long-term prospects for success with this approach. “Biological control of invasive weeds carries some risk, just as the other control methods,” Klepinger says. “However, we’ve learned that there is no risk-free way to manage loosestrife. If we do nothing, we risk continued degradation of our wetlands. This approach is self-sustaining and is beginning to show real results.” To become involved in the Purple Loosestrife Project, contact Klepinger at (517) 353-5508 or klep@msu.edu

Read more about the Purple Loosestrife Project online—http://www.miseagrant.org/exotic.html  The Web site also features an online bookstore with information about posters, field guides, ID cards, classroom materials and suggested activities to learn more about purple loosestrife. To order publications, send an e-mail message to: msgpubs@umich.edu, send U.S. mail to: Michigan Sea Grant, University of Michigan, 2200 Bonisteel Blvd., Ann Arbor, MI 48109-2099; call (734) 764-1118, or visit the Web site http://www.miseagrant.org

Michigan Sea Grant is a cooperative program of the U-M and Michigan State University in Great Lakes and marine research, education and outreach. Michigan Sea Grant is funded by the National Sea Grant College Program at the National Oceanic and Atmospheric Administration, a division of the U.S. Department of Commerce.

http://www.msue.msu.edu/seagrant/pp/

purple loosestrifeMichigan Sea GrantDepartment of Natural ResourcesPurple Loosestrife Projectklep@msu.eduhttp://www.miseagrant.org/exotic.htmlNational Sea Grant College Program