Pest profile

Rednecked Cane Borer

Agrilus ruficollis · Coleoptera: Buprestidae[2]

Rednecked cane borers can infest up to half the canes in young blackberry and raspberry plantings.[1]

Rednecked cane borer, a slender black beetle with a coppery-red thorax, on a leaf
Rednecked cane borer, a slender black beetle with a coppery-red thorax, on a leaf. (c) Will Kuhn, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Adults are slender metallic beetles about 1/4 inch, black except for an iridescent coppery-red to golden thorax.[1]
  • Larvae form swellings or galls 1 to 3 inches long on canes, often splitting the bark.[1]

Where it lives

It can be a serious pest of raspberries and blackberries throughout Kentucky.[1]

US map: public records from 36 states since 1990 (GBIF).

Biology and life cycle

Larvae overwinter in canes and adults emerge in early to mid-June.[1]

Larvae tunnel in a spiral around the cane and then up into the pith.[1]

Damage and signs

  • Infested canes die or become too weak to carry a crop, and girdled canes suffer more winter injury.[1]

Health risk

It feeds on plants; UK Extension mentions no risk to people.[1]

Control

Sanitation

During winter pruning, cut out galled canes and destroy them before bud swell, along with nearby sources.[1]

Pesticides

If pruning doesn't control heavy infestations, two sprays 7 to 12 days apart timed to adult emergence help.[1]

Common questions

What are the swellings on my blackberry canes?
Galls from rednecked cane borer larvae.[1]
When should I cut out infested canes?
During winter pruning, before bud swell.[1]

Sources

  1. University of Kentucky Entomology (ENTFACT), “Rednecked and Raspberry Cane Borers (ENTFACT-209).” entomology.mgcafe.uky.edu/ef209 (accessed 2026-10-06)
  2. iNaturalist, “Agrilus ruficollis taxon page (order and family).” www.inaturalist.org/taxa/130012 (accessed 2026-10-06)

Updated 2026-10-14. Built from sourced records. Spot an error? Tell us.