Clubroot in canola is caused by Plasmodiophora brassicae, a parasite that infects the roots of host plants and produces club-shaped galls that restrict the flow of water and nutrients. Plasmodiophora brassicae is an obligate parasite, meaning it cannot survive without a living host. Collecting Samples? Click Here. Additional information: 2016 Clubroot Survey Report Alberta AgricultureRead more