Pests & diseases › Cabbage Root Fly
Cabbage Root Fly
Small white maggots eat the roots of all brassicas. Plants wilt and collapse for no obvious reason.
Symptoms
- Brassica seedlings wilting and dying despite watering
- Outer leaves turning bluish-grey then yellow
- Roots eaten away — plants pull out easily with no root system
- Tunnels in swedes, turnips and radish roots
Lifecycle
Three generations: late April, June and August. Adults lay eggs in soil at the base of brassica plants.
What to do
- Pull and bin badly-affected plants
- Re-firm soil around survivors and feed with seaweed
If it's bad
- No effective home-garden insecticide
Stop it coming back
- Brassica collars (15cm disc of carpet underlay or roofing felt) around stems at planting
- Insect-proof mesh from planting to harvest
- Plant after early May to dodge the first generation
- Firm soil around stems — flies prefer loose soil
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.