Pear Sawfly

Pest Description

• 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

IPM Recommendations

• 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.