07-03-2007
State Researchers Testing 'Purple Traps' For Emerald Ash Borer Detection

Jane Cummings-Carlson (DNR)
(608) 275-3273

MADISON - If you happen to see a small, purple contraption hanging in a tree in one of 11 state parks or near any of a handful or so of rest stops, county parks, or communities in southern Wisconsin this summer, don't worry that some heartbroken child is missing a kite. The purple, triangular objects hanging in those trees are the latest tools to help researchers determine if the emerald ash borer has shown up in the state.

The purple objects are actually emerald ash borer traps. They are roughly two feet long, made from corrugated plastic, and coated with an adhesive that will capture the emerald ash borer (EAB) beetles if they land on it. Researchers will visit them every other week through the end of August to see if any beetles have been caught. Approximately 130 traps will be deployed this summer in Wisconsin.

"We're very excited about using this new tool to increase our chances of finding the emerald ash borer," said Jane Cummings Carlson, forest health coordinator for the Wisconsin Department of Natural Resources. "Detecting an infestation before it reaches a high population level can give us more options for management."

Research will continue to compare the effectiveness of the purple traps to the girdled detection trees that have been used in Wisconsin since 2004. Girdled trees are an effective way to locate infestations, but at the expense of the tree. If these traps eventually prove to be effective, girdled trees may become a smaller component of an early detection program.

"Girdled trees still offer the most reliable way to search for EAB in an area where there has yet to appear any physical signs of the insect," said Adrian Barta, EAB program coordinator with the Department of Agriculture, Trade and Consumer Protection. "But these traps do offer us a chance to do some survey work in areas where it hasn't been practical to girdle a tree."

DNR traps have been set up at 11 state parks. They are: Interstate, Peninsula, Thompson, High Cliff, North and South Units of the Kettle Moraine, Governor Dodge, Devils Lake, Mirror Lake, Rocky Arbor, and Richard Bong Recreation Area. DATCP has set up traps at five Dane County parks with campgrounds, the Pleasant Prairie landfill in Kenosha County, the woods at the state agriculture department building in Madison, and at eight rest areas on state highways near Dubuque, Beloit, Genoa City, Kenosha, Lake Mills, Johnson Creek, Portage, and Elkhorn.

"For some reason, EAB adults are attracted to the color purple," said Cummings-Carlson. "Federal researchers learned this while looking for new ways to survey for beetles."

Emerald ash borer is a small, green beetle that was first identified in 2002 near Detroit, Mich. Scientists believe it actually arrived in the United States in the early 1990s. Since then, it's responsible for the demise of nearly 25 million ash trees in the US and Canada. The EAB larvae feed just under the bark of ash trees, preventing the flow of water and nutrients in the tree. Unlike other native wood boring beetles, EAB attacks perfectly healthy ash trees, not just stressed trees.

A federal quarantine on hardwood firewood and a variety of ash products has been in place in Illinois, Ohio, Indiana and Lower Michigan since last December.

Wisconsin has approximately 725 million ash trees in forest settings. It's also estimated that ash species comprise about 20 percent of all street trees in the state.

Information about emerald ash borer and the problems associated with transporting pests and diseases in firewood can be found at the Wisconsin Emerald Ash Borer Resource here.

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