Bug Identifier
Pear Sawfly (or Pear Slug)
Community identification

Pear Sawfly (or Pear Slug)

Caliroa cerasi

Order & Family
Order: Hymenoptera, Family: Tenthredinidae
Size
Larvae typically range from 10-15 mm (0.4-0.6 inches) in length when fully grown. Adults are small, wasp-like insects, about 5-6 mm (0.2 inches) long.
See this bug in the Encyclopedia

Natural Habitat

Orchards, gardens, and areas where host plants from the Rosaceae family (especially pear and cherry trees) are present.

Diet & Feeding

The larvae feed on the epidermal tissue of the leaves of various Rosaceae family plants, particularly pear, cherry, plum, and sometimes quince, hawthorn, and apple. They skeletonize the leaves, leaving behind the veins.

Behavior Patterns

Larvae (slugs) are active during the day, feeding on the upper surface of leaves. They move with a slug-like motion, secreting a slimy substance. There can be multiple generations per year, with activity typically from late spring through fall. They overwinter as prepupae in the soil.

Risks & Benefits

Potential Risks: Pear sawfly larvae can cause significant defoliation, especially on young trees or during heavy infestations. This can weaken the tree, reduce fruit production, and make it more susceptible to other stresses. While they don't typically kill mature trees, repeated severe defoliation can be detrimental over time. Potential Benefits: No significant direct benefits are attributed to this species from a human or ecosystem perspective; they are primarily considered a pest in horticulture.