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May 10, 2011

Report sightings of invaders, grow special beetles

MADISON - Purple loosestrife and other invasive plants grew like gangbusters during last year's warm, wet summer, making citizen help in combating these invaders even more important this year, state officials say.

State invasive species control specialists are seeking groups to help raise special purple loosestrife eating beetles and to help report infestations of that and other invasive plants.

"The early wet, warm weather accelerated the germination, growth, flowering and spread of purple loosestrife, and other invasive plants last summer," says Brock Woods, the state's purple loosestrife biocontrol and wetland invasive plant coordinator. "We need citizens to help us roll back the gains invaders made last summer."

Purple loosestrife has been a serious exotic invader of Wisconsin wetlands for decades while nonnative Phragmites (giant reed grass) and Japanese knotweed are newer species of concern. All three grow taller than almost all other herbaceous plants, spread prolifically, and can quickly dominate large areas. They displace native wetland plants, degrade wildlife habitat, displace rare plants and animals and choke waterways.

An information sheet with photos of these and many other invasive wetland plants (pdf)] is available online, as is more detailed information about many invasive plant species.

Raising biocontrol beetles

Free equipment and starter beetles are available to anyone interested in helping raise special beetles that target only purple loosestrife.

"Raising and releasing these safe and effective beetles is a fascinating and easy project, but projects must start as early in spring as possible to be effective," Woods says. "We need some citizen cooperators who have released beetles in the past to put more of them out on old release sites, and new cooperators to help release them into new loosestrife patches."

People interested in raising the beetles can learn more about the project on the purple loosestrife biocontrol page of the DNR website, and can contact Woods at (608) 221-6349 or for details.

Careful research over two decades has shown that these insects feed on purple loosestrife and are not a threat to other plants, Woods says. Insect releases monitored in Wisconsin and elsewhere have also shown that these beetles can effectively decrease purple loosestrife's size and seed output, thus letting native plants reduce its numbers naturally through increased competition.

DNR and UWEX, along with hundreds of citizen cooperators, have been introducing natural insect enemies of purple loosestrife, from its home in Europe, to infested wetlands in the state since 1994.

Report sightings of invasive plants

Now is a good time to report patches of Japanese knotweed [/invasives/publications/pdfs/japanese_knotweed_brochure.pdf] and nonnative Phragmites and other plants that appear to be invasive and are just moving into an area.

Japanese knotweed is an upright, semi-woody herb with stems that resemble bamboo. Phragmites is spreading in wetlands near the Great Lakes and is moving inland along highway ditches. It has large, dark, fluffy flower tops and should be distinguished from the native strain by using information at [] (exit DNR).

Report populations of these invasive species by emailing exact location, land ownership if known, population size, your contact information, and a photo or voucher specimen to, or by calling by 608-266-6437. Details on reporting can be found on the DNR website.

FOR MORE INFORMATION CONTACT: Brock Woods (608) 221-6349; Kelly Kearns (608) 267-5066

Last Revised: Tuesday, May 10, 2011

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