Raspberry horntail—Hartigia cressoni
Horntail larvae are white and cylindrical, with dark heads and a short spine on the tail end. They have
three pairs of legs, no prolegs, and attain a length of up to 1 inch. The adults are wood wasps with long
cylindrical bodies with a spine at the tip. The females are marked with bright yellow and black; the males
are mostly black.
Tips of young shoots damaged by horntails wilt during the spring. The tips of the cane may girdle and
wilt. The cane may suffer dieback by the summer. Cutting open the affected portion of the cane may reveal
the thick white worm or the tunnel containing brownish granular material.
Regular pruning and disposal of wilted shoots
can eliminate raspberry horntail within 1 or 2 years. Inspect
canes regularly in spring and summer. Prune terminals off
just below any wilted leaves or just below a
pronounced swelling or discolored egg-laying incision that
may be visible on canes. Insecticide sprays are not recommended.