Hawthorn: 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.
The adult sawfly is a small, dark, wasp-like insect about 1/4″ long. The larvae feed on the leaves of cherry, plum, and pear trees, as well as hawthorn.
Leaves are typically skeletonized, with only the veins and lower leaf surface remaining. Heavily damaged leaves may drop from the tree.
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.
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, when practical.
- 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 :
- Apply if larvae are numerous or skeletonizing damage exceeds 25% of foliage.
- Thorough coverage is essential for products applied as foliar sprays.
- 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.