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Apple tree leaf spots #868330

Asked May 14, 2024, 6:12 AM EDT

I recently purchased an apple tree from Costco and planted it a month ago. It gets full sun. Many of the leaves have spots as shown in the picture. Please advise on the issue. Also, when should apple trees and other fruit trees be pruned? Thanks!

Washtenaw County Michigan

Expert Response

Hi Jenny,

The brown and black colored spots on the leaves are caused by a disease called apple scab.  This is a disease caused by a fungus.  I don't know if you are able to purchase a fungicide from a home and garden store to try to manage this disease.

Here are some links to MSU Extension articles about apple scab:

https://www.canr.msu.edu/ipm/diseases/apple_scab

https://www.canr.msu.edu/resources/apple_scab

Unfortunately, this disease is very difficult to manage.  One thing you can do in the fall, is rake up all of the leaves from under the tree and burn or compost them.  The fungus overwinters in the leaves and will infect your tree next year if those are not removed.

The raised orange-colored lesions on the leaves are caused by an insect.  These will not cause any major problems.

Pruning is best done after leaves drop in the late fall or in the spring before the tree leafs out.

Best regards,


George Sundin

An Ask Extension Expert Replied May 15, 2024, 1:48 PM EDT

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