Raspberry cane borer

Raspberry cane borer damage is visible and alarming when you first encounter it: a wilted, drooping growing tip on a healthy raspberry cane, with two neat rings of punctures an inch apart just below the wilt. This distinctive two-ring pattern is the female beetle's work -- she girdles the cane in.

Raspberry cane borer damage is visible and alarming when you first encounter it: a wilted, drooping growing tip on a healthy raspberry cane, with two neat rings of punctures an inch apart just below the wilt. This distinctive two-ring pattern is the female beetle's work — she girdles the cane in two rings to kill the tissue, then lays an egg in between the rings. The wilting tip is the result of the girdling, and the borer larva that will spend the next two years inside the cane is just beginning its work.

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

The pest

The raspberry cane borer (Oberea perspicillata) is a long-horned beetle (Cerambycidae). Per Penn State Extension, adults are:

• 12–15mm long, slender
• Black with yellow thorax (the section between head and wing covers) marked with two black dots
• Antennae as long as the body, characteristic of long-horned beetles

The species infects raspberry (Rubus idaeus), blackberry (R. allegheniensis), and rose (Rosa spp.).