Emerald Ash Borer Detected In Rusk County

By Paul Cigan, DNR Forest Health Specialist, Hayward
Paul.Cigan@wisconsin.gov or 715-634-9232

Photo of an emerald ash borer on a tree

Emerald ash borer was detected in Rusk County in northwest Wisconsin in late July, making it the 69th of Wisconsin’s 72 counties that have confirmed presence of the invasive insect. / Photo Credit: Paul Cigan, Wisconsin DNR

The emerald ash borer (EAB) has been detected for the first time in Rusk County, making it the 69th of Wisconsin’s 72 counties to determine the presence of the invasive insect.

On July 25, Wisconsin Department of Natural Resources Forest Health staff investigated a report of several ash trees with woodpecker flecking and branch dieback in a village park along Railroad Avenue in the Village of Sheldon.

Upon further inspection, almost a dozen ash trees growing in adjacent residential lots displayed woodpecker flecking. One adult EAB beetle was collected from an infested tree and officially confirmed as EAB by a USDA-APHIS identifier on Aug. 7.

There are no regulatory changes as a result of this detection because EAB was federally deregulated on Jan. 14, 2021, and Wisconsin instituted a statewide quarantine in 2018.

EAB was first found in the state in 2008.

EAB will continue to spread in northern Wisconsin, bringing a significant impact on the ash resource. This is a good time to review the updated Wisconsin DNR emerald ash borer webpage for information and resource links on EAB, and the Wisconsin DNR Emerald Ash Borer Silviculture Guidelines to become familiar with or to refresh on ash stand management options.

For information on insecticide treatment options for ash shade trees, please visit the University of Wisconsin-Madison’s EAB webpage.

The DNR, DATCP, UW-Extension and tribal partners continue to track EAB’s spread, sharing detection information through online maps available to Wisconsin’s citizens, private businesses and governmental entities. The effort is meant to aid in EAB readiness planning, pest management and biological control activities.

With 47 new city/town/village detections already reported statewide in 2023, map updates continue to occur on a biweekly basis. To see where EAB has been found in Wisconsin or to report new municipal detections, please visit the Wisconsin EAB online detections map or PDF map.

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