|my oak tree is ~15-20yo. it has brown/blackish spots on ~80% of the leaves. what is the most likely cause? and how can i treat it? thx rich|
That is either a fungal or bacterial leaf spot disease. The tree will be fine with no need for treatment. Besides it is pretty difficult if not impossible to effectively spray a tree unless you have some special equipment. I would just leave it alone and make sure it is well watered during droughts, especially in summer, and fertilized a little in the spring or early summer.
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