Orange galls, fuzzy galls or fuzzy orange galls, no matter what you call them if you have an oak tree in your yard or on your property you likely have them. The culprit is the Cynipid wasp, a tiny member of the Vespidae family that lays its eggs on oak tree leaves.
“The gall is the plant or tree’s reaction to the insect’s egg,” said Jim Dill, pest management specialist with the University of Maine Cooperative Extension. “The leaf tissue grows around the wasp egg.”
The gall then serves as a protective shell in which the wasp larvae can grow and feed, Dill said.
In the case of the fuzzy orange galls, these growths look like tiny balls of fluff. Early in the summer, they are a light tan. As the season goes on they start to darken until in late August and September they are deep orange and brown.