Jumping Oak Galls – Identification
Q: We live on a fairly large heavily wooded lot with mostly oak trees. The problem we’re having is with the white oak trees only. A couple of weeks ago we noticed little brown pinhead-size, seed-like things dropping from them. Each leaf on each tree is affected.
A: My guess is that you have a fine infestation of jumping oak galls. Have you seen them jump?
The small galls are formed when a tiny wasp lays her eggs on the leaf. Leaf tissue grows around the egg and a larva develops inside. At some point the larva(ae) start thumping around in their cells and lots of them dislodge from the tree. They keep moving after they hit the ground, jumping up to an inch high. They’re miniature versions of the Mexican jumping beans you played with as a kid!
Sometime there are so many that leaves fall from the tree but they don’t permanently hurt the tree. No control is necessary.
I doubt you’ll have such a problem next year.