"Mentor is the winter oilseed rape variety with a specific recommendation on the North region AHDB Recommended List,' says Craig Padley of breeders LS Plant Breeding Ltd (LSPB). "It is recommended for growing on land infected with clubroot and is resistant to common strains of clubroot, although not all.
"It is widely recognised that clubroot is an increasing problem in oilseed rape crops and one that had been intensified by too-close rotations.
"Symptoms are that plants can wilt in hot, dry weather and become very stunted or even die off completely. This is because the 'galls' on roots formed by the clubroot pathogen limits the oilseed rape plant's normal root function and reduces both water and nutrient uptake.
"And this is a problem that will be long-term one - once land is infected with clubroot spores, it could be up to 15 years before it is likely to be clean again.
"Growers should test soils for clubroot and pH, as acidic soils are more susceptible, and use the results to plan farm strategy.
"Preventative action is built round rotations that alternate oilseed rape with cereals and break crops such as pulses.
"Whilst Mentor offers varietal resistance to clubroot, it is important not to compromise this by going for short rotations. Rotations of greater than one year in five are the wise course of action,' Mr Padley advises.