How to Manage Pests

Pests in Gardens and Landscapes

Willow leaf gall sawfly—Pontania pacifica

The willow leaf gall sawfly is one of several similar species that cause nearly identical damage on willow throughout the United States. Adult males are shiny black; females are dull reddish.

Damage

Willow leaf gall sawflies apparently do not harm plants. Female sawflies insert their eggs in young willow leaves and inject a fluid that causes the formation of reddish, berrylike galls. One larva develops in each of these galls, which are globular or elongate and about 0.33 inch long.

Solutions

No controls are recommended or known for the willow leaf gall sawfly. The larvae of several wasps, and at least one weevil and moth, feed on the sawfly larvae or on the gall tissue, causing the sawflies to die. A wasp, Eurytoma sp., appears especially important in controlling willow leaf gall sawfly populations in California.

Willow leaf gall sawfly galls
Willow leaf gall sawfly galls


Statewide IPM Program, Agriculture and Natural Resources, University of California
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