Live Oak "Bulbs" with Holes: Insect Galls, Not Fatal

Woody Galls on Live Oak: Wasps, Not Killers

The “bulbs” with pin-sized holes on your live oaks are insect galls (likely gouty or horned oak gall wasps). Galls form when wasps lay eggs and secrete chemicals that force woody tissue growth. They take 2+ years to develop. Adults emerge in spring.

Management Reality

• Insecticides don’t reach larvae inside woody galls.
• Pruning infested twigs helps only on lightly infested small trees.
• Galls rarely kill the tree—they may cause some branch dieback.
• If the tree is dying, something else is the cause.

See PSU fact sheet.