Look for Signs of Emerald Ash Borer in Local Ash Trees

Friday, February 6th, 2026 -- 10:00 AM

Are you noticing trees in your community that resemble those shown in the photos?

These may be ash trees affected by Emerald Ash Borer (EAB), an invasive insect that poses a serious threat to ash tree populations. Winter is an ideal time to identify ash trees infected with EAB.

Common signs include bark discoloration, with bark changing from its normal gray or brown color to a lighter, whitish appearance. Bark may also begin to fall off as woodpeckers search for EAB larvae within the trunk and branches.

Another indicator is the presence of small, “D”-shaped exit holes in the bark, created as adult beetles emerge from the tree. Beneath the bark, serpentine tunnels, known as galleries, may be visible where the insects have been feeding.

Attached are two informational fact sheets that provide additional details about Emerald Ash Borer, its impacts, and available management options. Residents are encouraged to educate themselves about EAB to protect their ash trees or make informed decisions about treatment or removal.

If you are unsure whether you have an ash tree or suspect it may be infected, please contact a certified arborist for professional assistance. Additional resources and information about Emerald Ash Borer are also available on our Forestry Division webpage.

• WI DNR EAB Fact Sheet - Read or download the fact sheet
• EAB Dangers and Costs - Read about the EAB dangers and costs

(Image couresty of the City of Marshfield via press release)

Feel free to contact us with questions and/or comments.