Ornamental Plum: Pear slug
Photo by: R.D. Akre
Biology
Pear slugs, or pear sawflies, are insect larvae which resemble a small greenish or black slug. They are typically 1/4″ to 1/2″ long, tadpole-shaped, and produce large amounts of slime on their bodies.
The adult sawfly is a small, dark, wasp-like insect which is usually about 1/4″ long. The larvae feed on the leaves of plum, cherry, and pear trees.
Leaves are typically skeletonized (the upper layers of the leaf are eaten away, leaving only the veins and the lower leaf surface). Heavily damaged leaves may drop.
The pear slug can be found from mid- to late spring and again in late summer. There are two generations per year.
Management Options
See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.
Non-chemical Management
Select non-chemical management options as your first choice!
- Hand-pick and destroy individual larvae.
- Hose pear slugs from foliage with a strong stream of water.
Chemical Management
IMPORTANT: Always read and follow label directions when working with pesticides.
For more information on using pesticides visit :
- Chemical control measures are rarely necessary except for very severe infestations.
- Apply when larval damage approaches 25% to 30% defoliation.
- Homeowners should not make foliar applications to trees over 10 ft tall.
- Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.
Approved Pesticides
If you choose to use a pesticide, some examples of products that are legal in Washington are listed below. Some products are labeled for just INDOOR or just OUTDOOR use, or may allow both uses. Be sure to choose a product appropriate for your situation. Always read and follow all label directions.
WSU Extension programs and employment are available to all without discrimination.
Evidence of noncompliance may be reported through your local Extension office.