The P&PDL received this white oak sample. The galls look like clusters of tiny acorns on a branch and were caused by a cynipid gall wasp. These tiny insects cause a gall to form around them as they develop. Because the growth is actually plant tissue, it does little damage to the tree. No chemical controls are recommended. Pruning out and destroying galls will aid in reducing the population next year.
![]() |
![]() |
![]() |
| Cynipid Gall Wasp on White Oak | Cynipid Galls | Close-up of Wasp Larva in Gall |
|---|
|Top |
Plant and Pest Digital Library Project, Purdue University, West Lafayette, Indiana.