Oak: Leaf galls

Biology

Leaf galls are caused by the feeding of several species of oak gall wasp larvae. Typical galls are enlarged or swollen plant tissues. These may assume several forms, depending on the species of wasp. Galls may be round, smooth, woolly, spiny, thorn-like, or dish-shaped. Colors vary from white to bright red to greenish, depending on wasp species and age of the gall. Many galls are formed on the leaves, but some may be found on twigs. Leaf deformities and twig dieback can result from infestations.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Pick out and destroy galls when noticed (when practical). Many galls mature in the fall, so gall removal and destruction prior to this may help reduce numbers of wasps in the spring.
• Prune out unsightly galls to improve tree’s appearance, when practical.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• Non recommended