Common Insects and Mites: California gallfly

Biology

The gall of this cynipid wasp larva is the largest and most conspicuous of the galls on oak. It is a twig gall that is often called ‘oak apple’. It starts out green and gradually becomes red on the sunny side. Later in the season, the gall turns brown or grayish just before the adult wasps chew their way out. The gall does no apparent damage to the tree and is easily removed without harming the twig. The gall is generally round and sometimes kidney-shaped. During its development, the gall may host up to a dozen larvae.

Management Options

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

Non-chemical Management

Select non-chemical management options as your first choice!

• Hand remove where practical.

Chemical Management

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

None recommended.