Pest description and damage Pear slug is found in most areas of the U.S. It attacks pear, cherry and other ornamental Prunus. The adult is a glossy black fly-like insect, about 0.2 inch long. The larva initially resembles a small tadpole due to the olive-green slime that covers the body, and the head being wider than the rest of the body. Mature larvae are 0.375 inch long and orange-yellow. Larvae feed on the upper surface of leaves, skeletonizing them. Heavy feeding causes leaf drop, with reduction in vigor and yield, particularly on young trees.
For biology, life history, monitoring and management
Pear, flowering (Pyrus)-Pear sawfly (pear slug)
See Table 2 in: