Raspberry crown borer
Pennisetia marginata
10 host plants
Last updated
Look for a clear-winged moth resembling a yellow jacket, about 1 inch wingspan, with black body and four yellow abdominal stripes. White larvae with brown heads tunnel into crown tissue and roots at or below soil surface. Canes break easily during winter tying, and swelling with sawdust-like frass appears at entrance holes.
Inspect cane bases in winter and early spring for young larvae before they grow large. Remove and burn heavily infested plants. Ichneumonid wasp Pterocormus chasmodops provides natural control in Washington. Choose resistant cultivars and maintain optimal growing conditions to support crown vigor.
Quick Reference
The adult raspberry crown borer is a clearwing moth with a wingspan of 1" to 1 1⁄2". The moth closely resembles a yellowjacket. Females lay eggs on the canes or leaf margins. The caterpillars hatch by fall (around October) and overwinter in small cells near the base of the canes. In the spring, the larvae tunnel deeper into the canes and feed inside the canes. The canes may appear swollen or galled as a result. The caterpillars spend a second winter in the canes before emerging as adults the following summer. The larvae are white with brown heads. During the second winter they are typically 1⁄
Cultural Controls
- -cultural control Dig out and burn infested canes and crowns in the fall.
- Remove other hosts, such as wild blackberries, from the area.
- Management-