- adults: 1/5 inch; shiny black wasps; fly-like
- larvae: up to 1/2 inch long; covered in olive green to black slime; sluglike
- mature larvae: orangish yellow without the slimy coating
Host Plants, Diet & Damage
- primarily pear and cherry; cotoneaster, hawthorn, mountain ash, plum
- feed on plant tissue
- skeletonize the upper surface of leaves
- severe damage can cause brown leaves and leaf drop
- 2nd generation typically causes most of the damage
Biology, Life Cycle & Damaging Life Stage
- overwinter as pupae in the soil
- pupate in spring; adults emerge in late spring and mate
- females lay eggs into upper surfaces of leaves
- 1st generation eggs hatch in early summer; larvae develop through late July
- mature larvae drop from plants and pupate in the soil
- 2nd generation larvae are present in late-August and September
- mature larvae drop from the tree and overwinter as pupae in the soil
- two generations per year
- larvae are the damaging stage
- Manage trees to improve or maintain health.
- Monitor in July, late-August and September for larvae.
- Damage from low-level populations can be tolerated.
- Wash larvae off with a strong spray of water.
- Apply an insecticide (carbamate; insecticidal soap; pyrethroid; spinosyn) to foliage when larvae are present.
For more information, see our Pear Sawfly fact sheet.