How to Manage Pests

California willow leaf beetle
Plagiodera californica
The California willow leaf beetle feeds on willow leaves. Adults are shiny olive green to black beetles. Larvae chew pitted holes in leaf surfaces. Black larval frass may cover part of the chewed surface of the leaves.

Klamathweed beetle
Chrysolina quadrigemina
Klamathweed beetles feed on and can completely defoliate the groundcover, Hypericum calycinum. The metallic bluish green to brown adults feed on foliage the year round, except during the hot, dry summer. Larvae are grayish in color; they feed on leaves.

Elm leaf beetle
Xanthogaleruca or Pyrrhalta luteola
Elm leaf beetle feeds on elms and zelkova throughout the U. S. Larvae skeletonize the leaf surface, while adults eat through the leaf, often in a shothole pattern. Adults are olive green with black, longitudinal stripes along the margin and center of the back. Newly hatched larvae are black. Mature larvae are a dull yellow or greenish with rows of tiny dark tubercles that form two black stripes down the back. Pupae are bright yellow.