Oak Leaf Blister – Identification

Q: There is something weird on my oak leaves. A lot of lower leaves have the brown spots. Will it spread and kill the tree?

A: This is a fine example of oak leaf blister. The disease is favored by cool, moist conditions during budbreak and in the early stages of leaf development. It is common when we have cool, wet springs. Diseased areas grow slowly but the symptoms are very visible in midsummer.

It doesn’t seem to damage trees permanently. Given a dry spring next year, you may not see it at all. It will not harm trees as long as they don’t suffer from drought at the time the disease attacks them.

Be sure to rake and remove leaves in fall.

See Oak Leaf Blister

oak leaf blister


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