Hi, I have an oak tree that has fuzzy growths on the leaves. They look like...

Asked September 18, 2015, 8:27 PM EDT

Hi, I have an oak tree that has fuzzy growths on the leaves. They look like cotton. I thought they were galls but I just see a little seed like thing inside. What could they be? If they are galls can you give me a little more information such as what insect, how long do the take to mature? Is the gall specific to a tree species or to an insect? Photos attached.

Wright County Minnesota

2 Responses

The growth is the wooly oak gall. They rarely harm the tree and treatment is not recommended.
http://ouroneacrefarm.com/woolly-oak-galls-callirhytis-lanata/

The gall is specific to oak trees and a specific insect lays its eggs on oak. The gall is the oak leaf response to an insect that lays its eggs on oak leaves.