Club root (Plasmodiophora brassicae)
A serious disease which infects the roots, causing swelling and distortion as it creates a gall from which spores are eventually released. This fungus-like organism, related to powdery scab in potatoes, leads to poor growth and even death.
- Poor growth
- Foliage wilts in dry weather, recovering when wet
- Foliage discoloured - purple tinge
- Roots swollen and distorted
Prevention & control
- Ensure that the disease isn't brought on to your plot on seedlings.
- Lime soils below pH 7.0 and avoid poorly drained soils.
- Practise good, long rotations.
If you do get the disease:
- Remove and burn the whole crop.
- As well as not planting brassicas (including brassicaceous green manures) for several years, keep potential host weeds (e.g. shepherd's purse) at bay.
- The spores can survive for 20 or more years, so choose resistant varieties and plant in trenches filled with clean compost to allow roots to develop well before coming into contact with the disease.