Question
Many of the leaves on our white oak tree have yellow, yellow/pink fuzzy round balls on them. Are these balls an insect? Many of the leaves also have holes in them. Are the fuzzy balls eating the leaves? The tree has some disease, but I cannot identify it.

Answer
Debbie:
These fuzzy balls are probably some type of a gall insect.  Google "oak galls" and take a peek at the images of the various types.  No feasible trt recommended. If it is what I am thinking of these critters won't have an adverse impact on the health of the tree- Just rake up these leaves and discard- particul;ary during the winter since these things can overwinter in the Galls.

Be sure to water your trees well, and keep stringtrimmers and lawnmowers away from them.

Steve