Pear and Cherry Slug Control © Frances Michaels

This pest eats the leaves of pears, cherries, plums, apples, quinces and hawthorns. The adult is a glossy black sawfly; it lays eggs in the leaf, which become slug-like larvae. After feeding on leaves, they drop to the ground and dig into the soil, where they pupate. Adults emerge and fly to the leaves to lay more eggs. There are 2 generations a year; the first larvae appear on trees in early summer. These become adults in December and January. The second generation is usually more of a pest than the first, more numerous and widespread. Some of the larvae over-winter underground to emerge the following spring to start the cycle again.

Suggested Organic Strategies

• Hose them off the leaves with a strong jet of water.
• Band the tree with a horticultural glue to prevent them climbing back up.

• Encourage natural predators such as paper wasps, hoverflies, lacewings, spiders and insect-eating birds.
• Fence bantams under the tree during winter to destroy overwintering pupae.
• Stand upwind of the tree and throw ash over it.

Suggested Products:
Horticultural Glue

Photograph courtesy of Judy Horton of Yates