My oaks has so many knots on the branches. some of the knots has small holes on it? I am worry about the tree so much.
waiting for you advice
Tks & B RDGS
Those are galls from insects. They don't harm the tree much and tend to come and go with different years. It is not practical to try and spray for them. If you keep the tree well watered in the heat of summer and fertilize the lawn beneath the tree, that tree will be plenty vigorous and able to more than overcome the problem caused by the gall forming insects.
Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!