Emerald ash borer confirmed in Eau Claire County

Wisconsin State Farmer
The emerald ash borer is eating its way across more and more Wisconsin communities.

MADISON – Emerald ash borer has been found on the campus of the University of Wisconsin-Eau Claire, the first time it has been seen in Eau Claire County, and the Wisconsin Department of Agriculture, Trade and Consumer Protection will quarantine the county as a result.

Department of Natural Resources staff collected larvae, or immature insects, on Nov. 27 from a tree on the campus. It had been heavily damaged by woodpeckers feeding on the larvae under the bark. City forestry staff also found several additional infested trees nearby. DATCP submitted samples to the USDA Animal and Plant Health Inspection Service for official confirmation.

For private citizens, the quarantine means that they cannot take firewood from quarantined counties to non-quarantined counties. For businesses handling wood products that could carry EAB, it means that they must work with DATCP to assure that their products are pest-free before shipping.

"Although we have now found EAB in 48 counties, much of the area in those counties remains uninfested. These scattered infestations are caused by human activity, not natural spread of the insect. So, it's still important for people not to move firewood out of infested areas, even within their own quarantined counties," said Brian Kuhn, director of the Plant Industry Bureau within DATCP.

That precaution can delay introduction to new areas of quarantined counties and give communities and property owners more time to prepare. It can also prevent moving other pests that might be hiding on or in firewood, such as gypsy moths or even pests that no one is yet aware of.

Larval tunnels of the emerald ash borer disrupts the flow of water and nutrients, and ultimately kills the tree.

Kuhn recommends that property owners in quarantined counties:

  • Watch ash trees for signs of possible EAB infestation: Thinning in the canopy, D-shaped holes in the bark, new branches sprouting low on the trunk, cracked bark, and woodpeckers pulling at the bark to get to insect larvae beneath it. 
  • Consider preventive treatments if their property is within 15 miles of a known infestation. Whether to treat depends on several factors: the age of the trees, the size of the trees, and the number of trees. Treatment costs vary depending on size of the tree and whether you do the treatments yourself or hire a professional.
  • Consider planting different species of trees that are not susceptible to EAB.
  • Contact a professional arborist for expert advice, and visit emeraldashborer.wi.gov for detailed information. 

Emerald ash borer is native to China and probably entered the United States on packing material, showing up first in Michigan in 2002.

It was found in Wisconsin in 2008 in Washington County. Eau Claire County joins 47 other Wisconsin counties where EAB has been found: Adams, Brown, Buffalo, Calumet, Chippewa, Columbia, Crawford, Dane, Dodge, Door, Douglas, Fond du Lac, Grant, Green, Green Lake, Iowa, Jackson, Jefferson, Juneau, Kenosha, La Crosse, Lafayette, Manitowoc, Marathon, Marinette, Marquette, Milwaukee, Monroe, Oneida, Outagamie, Ozaukee, Portage, Racine, Richland, Rock, Sauk, Sawyer, Sheboygan, Trempealeau, Vernon, Walworth, Washington, Waukesha, Waupaca, Waushara, Winnebago and Wood.

Kewaunee County is also under quarantine because of the proximity of infestations in neighboring counties.