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.
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.
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.
leaf gall sawfly galls