04-14-2008
Sticky, Purple Traps for EAB Survey

The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) will continue looking for signs of the emerald ash borer this spring and summer by deploying approximately 3,600 purple, sticky traps in ash trees across the state. This "purple trap survey" for emerald ash borer (EAB) is part of a nationwide effort paid for by the US Department of Agriculture. Portions of 46 states will be included in the survey, using approximately 60,000 traps.

State researchers have relied on girdled and felled trees - stripped of bark - in numerous locations throughout the state to help track down the tiny beetle. While trap trees are still considered an effective method to detect EAB, the purple traps offer a less destructive and lower cost option.

"Scientists have been working to develop survey tools to help search for emerald ash borer since the beetle was first identified in Michigan in 2002," said Melody Walker, DATCP's Pest Survey and Control Section Chief. "This survey device represents the very latest tool that we have available in the battle against EAB."

The purple traps will be hung from ash trees by hooks, out of the reach of pedestrians or passers-by. The three-sided trap is about two feet tall and little more than a foot wide on each side. Each one is coated with a sticky substance that will ensnare the adult beetle. A Manuka oil lure will also be hung within each trap, to help draw nearby beetles to the tree.

In scientific studies, beetles were attracted to the color purple. The lure, derived from New Zealand's Manuka tree, is similar to the chemical compounds that ash trees release when they are stressed. The combination appears to be appealing to the emerald ash borer.

Traps will be inspected after several weeks, with workers looking for adult emerald ash borer beetles and refreshing the lure. In the fall, when the beetles are no longer flying, the traps will be collected and reinspected for beetles.

Approximately three-fourths of the traps in Wisconsin will be placed in a grid pattern in 19 southern and southeastern counties, including all or parts of Kenosha, Racine, Walworth, Rock, Green, Lafayette, Grant, Iowa, Dane, Jefferson, Waukesha, Milwaukee, Ozaukee, Washington, Dodge, Columbia, Sauk, Fond du Lac, and Sheboygan.

"These locations fall within 100 miles of the infestations in northern Illinois," Walker said. "Other locations in the state that are further away, but still have some risk for EAB introduction, will also be surveyed."

Seventeen seasonal employees will begin setting out the traps for DATCP beginning the week of April 28.

EAB has already killed nearly 25 million ash trees in several states and Canada. It has been spread widely due to the movement of firewood. To date, emerald ash borer has not been detected in Wisconsin.

Wisconsin is home to more than 725 million ash trees in forest settings and more than five million in cities and villages.

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