Calcium and pH as Parts of a Coherent Control Strategy for Clubroot Disease (Plasmodiophora brassicae)

Commercially sustainable and environmentally acceptable control of clubroot disease caused by Plasmodiophora brassicae can be achieved by integrating land management, crop husbandry, crop nutrition and where available pathogen resistant cultivars and agrochemicals when accepted by the regulatory authorities. Manipulation of supplies of calcium, boron, nitrogen and soil pH values is associated with advantageous changes to soil microbial populations and diminution of the efficiency of stages in the pathogen life cycle. These effects allow the host - pathogen relationship to be rebalanced in favour of the crop plant. Fertilisers of especial value in achieving rebalancing are calcium cyanamide and calcium nitrate. Examples of their effects are given.