Maple tree problem

Asked May 20, 2014, 6:39 PM EDT

I have two Maple trees, about 7 years old. A large percentage of the leaves on both trees have some type of infection that is causing black spots as shown in the attached photo. Other trees in my yard (different variety) don't seem to be affected. Does anyone recognize what this is and could give me advice on what to do about it? Thank you in advance.

Washington County Oregon

1 Response

Hello and thanks for submitting your photo. We could be mistaken, but we think this looks like anthracnose, a class of fungal diseases that affect many types of plants including maples. The following information is paraphrased from the Pacific Northwest Disease Management Handbook: Anthracnose is typically a cosmetic problem and does not kill the tree. Warm, wet conditions exacerbate the disease. When the leaves drop in fall, rake them up and destroy them to prevent reinfection. You may also see twig cankers which are small, discolored or sunken areas on the twigs. If you see them, you can prune off and remove the affected twigs in the dormant season.
Hope this helps.