WSU Extension

Hortsense

Common Insects & Mites : Pear slug
(revision date: 4/30/2013)


Biology
These bizarre creatures are not really slugs. They are the larval form of a sawfly, a primitive group of wasps. They typically skeletonize the leaves of such trees as pear, cherry, hawthorn, plum, and mountain ash. Pear slugs are typically 1/4" to 1/2" long and tadpole-shaped. The adult sawfly is a small, dark, wasp-like insect about 1/4" long. Each time pear slugs molt, they secrete a moist body covering that darkens with time. Prior to each molt, they appear black. Immediately after molting, however, they appear olive green. The pear slug typically has two generations per season and can be found on trees from mid- to late spring and again in late summer. The second brood usually is the most devastating and often requires attention.
Management Options

Non-Chemical Management
  • Hand-pick and destroy individual pear slugs.
  • Wash pear slugs off foliage with a strong stream of water.
Select non-chemical management options as your first choice!

Chemical Management

Insecticide applications may be effective. However, the insecticide applied must be labeled for the host plant. Refer to the fact sheet on pear slug for that host.

Images
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Caption: Pear slug and damage
Photo by: R.D. Akre