How to Manage Pests

Pests in Gardens and Landscapes

Pear sawfly (Pearslug, Cherryslug)—Caliroa cerasi


Adult pearslugs are small, glossy black sawfly wasps about 0.2 inch long. The newly hatched larvae are white with a yellowish brown head. Almost immediately after hatching, the larva exudes an olive green coating that covers its body and gives it the appearance of a slug. The head end is wider than the rest of the body and a fully mature larva is about 0.5 inch long.

Life cycle

Adult pearslug wasps emerge from soil in early spring and lay eggs in leaf tissue. Mature larvae enter soil to pupate. Second-generation wasps appearing in summer do most of the damage. There are two generations a year.


Larvae skeletonize leaves and may remove all tissue except for the fine network of veins. Leaves with brownish patches result from the top layer having been eaten. High populations may reduce fruit size.


Pick pearslugs off by hand and dislodge them from foliage with a strong stream of water. Spinosad or insecticidal soap may be effective. Road dust or ash applied to foliage has been effective in killing pearslugs. Such dusts should be washed off after several days to discourage spider mites.

Pearslug larva
Pearslug larva

Skeletonized leaves caused by pearslugs
Skeletonized leaves caused by pearslugs

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