Emerald ash borer confirmed in Green County

An invasive species that’s destructive to ash trees was found for the first time in Green County, a government agency confirmed Monday. 

The Wisconsin Department of Agriculture, Trade and Consumer Protection said in a news release Monday that emerald ash borer beetles were found in a tree in a private yard in Decatur.

Brian Kuhn, director of DATCP’s Bureau of Plant Industry, said Green County has been under quarantine for EAB for nine months due to the beetle’s presence in neighboring counties.

“We quarantined Green County last July, along with Richland, Iowa and Lafayette counties, even though we had no confirmed findings of EAB there,” Kuhn said in the release. “This block of counties was surrounded at that point by quarantined counties, which leads us to suspect that EAB is present in low numbers that are difficult to detect. The Green County find confirms this.”

A private homeowner in the town of Decatur notified the Wisconsin Department of Natural Resources after seeing woodpecker damage and serpentine tunneling made by EAB larvae under the tree bark. Woodpeckers tear bark from infected trees as they feed on the larvae. DATCP said samples of EAB larvae were collected last Wednesday, and the U.S. Department of Agriculture confirmed Friday that they were EAB.

Quarantines prohibit ash wood products and hardwood firewood from being moved to areas that are not quarantined, DATCP said.

Businesses handling wood products that could carry EAB must work with DATCP to ensure that the products are pest-free before shipping them to non-quarantine counties.

For private citizens, a quarantine means that residents may not take firewood from the affected counties to non-quarantine counties. Kuhn said moving firewood within quarantined counties is legal but “strongly” discouraged, as that has been the cause of the “vast majority of EAB infestations.”

DATCP recommended that property owners who have ash trees in quarantine counties:

Keep a close watch for possible signs of EAB infestation: Thinning canopy, D-shaped holes in the bark, cracked bark, branches sprouting low on the trunk, and woodpeckers pulling at bark
Consider preventive treatments if your property is within 15 miles of a known infestation
Consider planting different species of trees that are not susceptible to EAB
Visit emeraldashborer.wi.gov for information

Emerald ash borer is native to China and probably entered the United States on packing material, showing up first in Michigan in 2002, according to the release. EAB was first found in Wisconsin in 2008 in Ozaukee County.

Wisconsin’s quarantined counties include Adams, Brown, Buffalo, Calumet, Columbia, Crawford, Dane, Dodge, Door, Douglas, Fond du Lac, Grant, Iowa, Jefferson, Juneau, Kenosha, Kewaunee, La Crosse, Lafayette, Manitowoc, Milwaukee, Monroe, Oneida, Outagamie, Ozaukee, Racine, Richland, Rock, Sauk, Sheboygan, Trempealeau, Vernon, Walworth, Washington, Waukesha and Winnebago.

EAB adults lay eggs on the bark of ash trees in mid- to late summer. When the eggs hatch a week or two later, the larvae burrow under the bark for the winter and feed, forming the characteristic S-shaped tunnels and destroying the tree’s ability to take up nutrients and water. In summer, the adults emerge through D-shaped holes in the bark.