Pests & diseases › Spotted Wing Drosophila
Spotted Wing Drosophila
Invasive fruit fly (SWD). Females lay eggs in ripening berries — soft fruit collapses within days.
Symptoms
- Soft berries that collapse on the cane within 24 hours of ripening
- Tiny white maggots inside fruit
- Worst on raspberries, blackberries, blueberries, cherries
Lifecycle
Multiple overlapping generations July to October. Established across UK since 2012.
What to do
- Pick fruit early — even slightly under-ripe — and refrigerate immediately
- Bin (don't compost) any maggoty fruit and any windfalls
- Trap with apple cider vinegar in jars (helpful indicator, small reduction)
If it's bad
- Spinosad-based products (UK home garden use restricted) — check current registration
Stop it coming back
- Fine 0.8mm mesh over cropping bushes — gold standard
- Pick every two days during peak season
- Hygiene: no rotten fruit on the ground anywhere on the plot
Crops it goes for
Plan the plot, track every sowing, cook the harvest
Sowing reminders and harvest forecasts for your own frost dates, the Seed Tin, Scan Centre for any label or packet, and the Potty Mouth Garden Club. Free to start.