Peach tree borer

The peach tree borer (Synanthedon exitiosa) kills more young peach trees in the eastern US than any disease. It attacks the trunk at and below the soil line -- exactly the area least likely to be inspected -- where larvae feed on the bark and cambium tissue, girdling the trunk over one or two.

The peach tree borer (Synanthedon exitiosa) kills more young peach trees in the eastern US than any disease. It attacks the trunk at and below the soil line — exactly the area least likely to be inspected — where larvae feed on the bark and cambium tissue, girdling the trunk over one or two seasons. A young tree that seems to be declining without obvious cause often has a peach tree borer infestation at the base that has been active for months.

I don't grow peaches at my Long Island property, so this guide draws on Penn State Extension, Cornell Cooperative Extension, and Clemson HGIC research.

The pest

The peach tree borer (Synanthedon exitiosa) is a clearwing moth (Sesiidae). Per Penn State Extension, adults:

• Are wasp-mimics with clear wings (wing scales are shed on emergence) and banded abdomens; females are metallic blue-black with an orange band on the abdomen; males are smaller and have yellow-and-black banded abdomens
• Are active in late summer (July–September in most of the mid-Atlantic and Northeast)
• Lay eggs on the trunk base and in bark crevices near the soil line

Per Cornell Cooperative Extension, the larvae:

• Hatch and bore into the bark and cambium at and just below the soil line
• Feed through the fall, overwinter as larvae in the feeding gallery, and resume feeding in spring
• Complete development by late spring–early summer of the following year; mature larvae are 1–1.25 inches, cream-colored with a brown head

The species infests peach, nectarine, plum, cherry, and occasionally apricot and ornamental Prunus.