Clubroot

Brassicas stay small, turn yellow and wilt on warm days, recovering at night. The roots are swollen into knobbly clubs and later rot away.

A soil-borne organism (Plasmodiophora brassicae) that thrives in wet, acid soil and whose spores survive in the ground for up to twenty years.

What can you do?

1. Pull up affected plants with all their roots before the swellings rot and put them in the general waste, never on the compost heap.
2. Lime acid soil to a pH above 7 and make sure it drains well.
3. Don’t grow cabbage, radish, turnip or mustard on infected soil for at least seven years, or choose resistant varieties.
4. Clean boots and tools so you don’t carry infected soil to other beds.

Prevention

Rotate brassicas every year, raise your plants in clean compost and keep the soil from getting too acid.

When to watch out: June–September

Diseases and pests · All species