Oak Apple Galls on Post Oak

Kalina Post Oak Leaf 3

Mature post oak (construction damage recovered). Hard freeze at bloom, then hail storm. Now yellow hollow balls on leaves—spider eggs?

Diagnosis: Oak Apple Gall

• Cynipid wasp galls on leaf midribs/stems.
• 0.5-2" diameter, fibrous interior, single larva in hard capsule.
• Green in spring → light brown papery shell.
• Primarily on red, black, scarlet oaks.

Impact

Leaf galls cause minimal harm vs. twig galls. Heavy infestation → premature leaf drop, unsightly. Natural enemies control wasps. Pick/prune off small trees.

No treatment needed—cosmetic only. Tree health unaffected.

Wikipedia: Oak apple.