How to Manage Pests

Pests in Gardens and Landscapes

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.

Life cycle

Damage

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.

Solutions

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.

Horntail larv and frass
Horntail larva and frass

Prune off terminals
Prune off terminals


Statewide IPM Program, Agriculture and Natural Resources, University of California
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