Hymenoptera: Cynipidae

Identification
• Both galls occur as brown woody masses up to 2" in diameter around twigs and branches.
• Horned oak galls have ¹/₈" horns protruding on all sides through which the tiny adult wasps emerge. (a)
• Gouty oak galls have no horns. (b)

Damage
• Branches sometimes die back due to the girdling galls.
• Horned oak gall attacks pin, scrub, black, blackjack,  and water oaks.
• Gouty oak gall attacks scarlet, red, pin, and black oaks.

Management
• Prune off and destroy twig galls on young trees where dieback could cause tree deformation.
• Systemic insecticide applied in the spring may be effective—particularly on horned oak gall.
• Tolerate the galls on larger trees.

Other Information
• Horned oak gall occurs in the spring as a blister gall along a vein. Adult tiny wasps emerge from the gall in mid-summer and attack the branches. Branch galls appear the following spring and take 2 years to mature.