Can you suggest what to do with a locust tree with peeling bark?

Asked November 16, 2013, 2:27 PM EST

I am looking for help diagnosing a problem I see on our locust tree. I can't remember if it's a sunburst or honeylocust. The problem, as you can see in the attached photo, is bark peeling off with "sawdust" behind it - possibly from some type of insect, or rotting? This is occurring in an area between 18" to 36" above the base of the tree - all on the north half of the trunk. This is an urban setting. Any direction you can provide would be most appreciated.

Lyon County Minnesota

1 Response

The damage appears to have been done by boring insects, probably a kind of beetle.

According to the U.S. Forest Service, Agrilus difficilis, a flatheaded borer, important west of the Mississippi River, burrows beneath the bark and may eventually girdle the trunk or large limbs. Several other bark and wood borers attack honeylocust, such as the widely distributed Xyleborus saxeseni."

What appear to be D-shaped exit holes on the tree in the photo suggest the presence of Agrilus difficilis (also known as the honeylocust borer).

Go to this website for more information about A. difficillis:

Information at these websites may also interest you:

Insect and Mite Pests of Honeylocust

Ornamental Pests: Borers

The damage shown in the photo appears to be advanced. We advise asking a certified arborist to assess the tree's health and determine whether anything can be done to save it.