Hawthorn: Pear slug

categories: Hawthorn Hawthorn Insects Ornamental trees Ornamentals

revision date: 2022-11-22 03:33

Pear slug and damaged leaf from feeding.
Pear slug and damaged leaf from feeding
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

Use Integrated Pest Management (IPM) for successful plant problem management.

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: Visit Home and Garden Fact Sheets for more information on using pesticides.

  • 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

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.