Oak Tree Disease

Asked September 1, 2016, 1:44 PM EDT

I have approximately 25 oak trees in my back yard. I have been told that approximately 75% of them are red oak and the remaining 25% are white oak. I also have a very large, old burr oak. Last summer one of the trees died. This summer, another tree died, and the "stem" of a third tree has died. I have had three different arborists come to my home to analyze the trees. Two have told me that I have oak wilt. (One of these arborists took leaf samples from the large burr oak as well as from two other trees to be submitted to the UofM extension service for analysis.) The third arborist has diagnosed the problem as armallaria. The dead trees obviously need to be removed. I'm just not sure who to believe and what the next course of action after tree removal should be. Please help!!

Carver County Minnesota tree health oaks tree diseases

1 Response

Thank you for the question. An accurate diagnosis of the problem(s) is vital to taking the next step. Diagnosing tree problems can be quite difficult and our best advice is to make sure that the arborist you hire is a certified professional. Here is a link with more information: http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/how-to-hire-a-professional-arborist

We assume that the samples submitted by one of the arborists went to the plant disease pathology lab. Have you followed up with the arborist on the results of this testing? Along with the results, you should get advice on how to proceed with treatment or tree removal from the arborist. Submitting samples for accurate diagnosis seems like a wise approach.

Here is good information on oak wilt and armallaria:

We can't tell you what to do but maybe now you can make a more informed decision.

Best of luck and thank you for consulting Extension.