How can I treat a pin oak tree that is heavily infested with those ugly, hard twig galls?
These ugly growths, gouty oak gall and/or horned oak gall, may cause severe injury and may even, in extreme cases, lead to the death of the tree. They are initiated by small, female wasps which deposit their eggs in small pockets which they cut in oak twigs from May to July. The galls develop over two or three years to protect the maturing larvae which then emerge as adult wasps to begin the process over again. Control of these offending wasps is nearly impossible, and no successful techniques appear in the offing. Since a severely infested tree poses a continuing threat to its pin oak neighbors, removal may be your best course of action.
