Plasmodiophora brassicae causes the club root disease of crucifers can be controlled by

Plasmodiophora brassicae causes the club root disease of crucifers can be controlled by Raising the pH of the soil.
Clubroot is a fungal disease that affects several plants in the cabbage family including cabbages, radish, mustard and ornamentals such as candytuft.
It is caused by the fungus Plasmodiophora brassicae and gets its name from the club-like roots it induces in infected plants.
Clubroot thrives in acidic soil, so raising the pH to at least 7.2 may be one of the most effective means of attaining clubroot control.