Clubroot is being reported in brassica crops across many regions, including in fields not previously affected.
Thanks to a mild autumn and warm, wet soils, conditions have been perfect for brassica infection by clubroot, says ADAS crop pathology research scientist Julie Smith.
The pathogen can result in loss of 50 per cent of yield potential in severely-affected crops.
As above-ground symptoms such as stunting and wilting are not yet apparent, growers should inspect their crops by pulling plants from across the field, she advises.
Dr Smith says: “Clubroot control is particularly difficult because the pathogen remains dormant for approximately of 15 years. The half-life of resting spores is four years, so rotations should be longer than this where clubroot is known to be a problem.”
Field trials carried out by ADAS have shown yield responses of more than 2t/ha (0.8t/acre) can be achieved by sowing a resistant variety. However, although resistant varieties are available, they are not resistant against all strains of clubroot present in the UK.
A new qPCR test which detects club root resting spores in soils has recently been developed by the University of Worcester through AHDB funding and is expected to be available in laboratories soon.