Q: These leaves fell from a large oak tree this week. A couple of weeks ago my patio was covered with the small rust/orange colored dots which appear on the leaves. Today I finally looked up to see the tree being defoliated before my eyes. What is it?
A: It’s jumping oak gall infesting your tree. 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 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.