Oak Tree Fungus or? - Ask Extension
We have an Oak in our yard, it's about twenty years old. This summer the leaves have begun to turn brown, it doesn't appear to be a mite or insect. C...
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Oak Tree Fungus or? #766218
Asked August 07, 2021, 1:18 PM EDT
We have an Oak in our yard, it's about twenty years old. This summer the leaves have begun to turn brown, it doesn't appear to be a mite or insect. Could this be a fungus and should we consider trying to treat the tree in some way to address the issue?
Pictures included.
Thank you.
Larimer County Colorado
Expert Response
Hi Catherine,
This looks like oak leaf blister, which is a fungus and is caused by cool, wet springs. At this point, there isn't anything you can do. It really doesn't affect the overall health of the tree or its growth--it's more aesthetic than anything else.
It doesn't usually warrant treatment, but fungicides can be applied at budbreak if a wet spring is predicted (anyone's guess!). Here is more information: https://extension.usu.edu/pests/ipm/notes_orn/list-treeshrubs/oak-leaf-blister
