Finding Emerald Ash Borer In The Winter Time

The Emerald Ash Borer (EAB) has become the scourge of Ash trees in Southeast Wisconsin.  There has been a large public awareness campaign by the DNR and companies like our ours to educate property owners on the signs and symptoms of an EAB infestation.  As a result many clients already know that crown die-back and excessive low sprouting can be signs of trouble.  However, ash trees are susceptible to other issues as well and these signs don’t always mean EAB.

The devastating Emerald Ash Borer (EAB) continues to be on the march in south east WI.  This winter offers an excellent time to examine your trees for the signs of Emerald Ash borer as many of the indicator signs are on the main trunks and stems and can be easily seen without being obscured by leaves.

In the winter time one of the clearest signs to look for is flecking bark.  This is when bark starts to peel off the main limbs of the Flecking barktree (often higher up in the canopy) You will notice a distinct tannish color where the bark has peeled off. When ash trees get to this point, it is common to see and hear woodpeckers tapping away at the trees, looking for EAB larvae and leaving large holes in their wake.

Vertical bark splits are another symptom.  The female beetles lay eggs in their galleries beneath the bark of an Ash Tree. The vertical bark splits are a result of the tree responding to the infestation. S-shaped larval galleries are sometimes visible beneath the cracks. It is these galleries that create the tree’s response. The exit-holes that the beetle creates to escape the dying tree will also be more visible in the dormant season. The holes are D-shaped and about ⅛ of an inch in diameter.

Live budsDead branches in an ash tree may be caused by EAB or could be from numerous other afflictions that can damage ash trees. The key to spotting deadwood in the winter time is to look for vibrant leaf buds at the tips of the branches. Healthy leaf buds are plump and already formed by the time the leaves fall off in the fall.  If the buds are not formed then the tips have died back and will not recover.  

What should you do if you think you have an infestation of the EAB in your landscape?  Call Hoppe Tree Service (414-247-2111) or visit our website ( to set up an appointment with a Certified Arborist.Flecking bark

Our Arborists will be able to help you decide on a course of action that is appropriate for your trees. We can take a preventive approach in trees that show no signs and exhibit no symptoms, or we can take a curative approach. The preventive approach is recommended for anyone with an Ash Tree in the landscape that is looking good and making positive contributions. The curative approach is taken when the tree is infested but still provides an important contribution to the landscape. The curative approach involves treating the tree for EAB and then monitoring the results. The results of the injection treatment have proven effective in both approaches.

If you have Ash trees, winter can be a great time to assess their health.  If you notice any of the signs or symptoms of EAB, call Hoppe Tree Service 414-257-2111 to set up a free appointment with a Certified Arborist to help you determine a proper course of action!

By: Will Martens

Certified Arborist WI-0646A

Hoppe Tree Service



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