Raspberry Beetle
Risk near you, next 48h
See whether your local forecast favours this disease right now.
When it strikes
Treat, then re-check in 5–7 days
Pick off the worst material, apply the organic option below, and look again after five to seven days. If the spread continued, escalate rather than repeating the same treatment.
Carried by insects
An insect moves it plant to plant, so controlling the carrier matters as much as treating the symptom. Check for the vector before assuming the plants infected each other directly.
Safe to compost
No pathogen carries over on this material, so it can go on an ordinary heap with the rest of the garden waste.
When and where to look
Scout the planting while temperatures hold between 15°C and 28°C.
Rule these out first
Same category, and at least one host crop in common — so they are genuinely confusable in the same part of the garden.
The signs that lead here
Full problem lists for these crops
About
Raspberry beetle (Byturus tomentosus) is the reason for the small white grub found in a picked raspberry. Adults feed on the flowers in May and June and lay eggs in them; the larvae then develop in the ripening fruit and feed at the stalk end.
Symptoms
Dried, browned patches at the stalk end of the fruit, and a small cream-coloured grub in the core when the fruit is picked or eaten. Flowers may show feeding damage earlier in the season.
Organic Treatment
Summer-fruiting raspberries are hit hardest, so growing autumn-fruiting varieties, which flower after the beetle’s main flight, sidesteps the problem almost entirely. Cultivate the soil beneath the canes in winter to expose overwintering pupae to birds and frost.
Chemical Treatment
A pyrethroid applied when the first fruits turn pink is the traditional timing, but it must never be used during flowering because of the risk to pollinators.
Prevention
Switch to autumn-fruiting varieties where the beetle is a persistent problem, hang a white sticky trap to monitor the flight, and keep the ground under the canes cultivated and clear.
Crops at risk
Related problems
Raspberry Beetle risk by location
Each location has a month-by-month profile computed from the weather archive: how many hours a year actually meet this disease’s thresholds.