Replication data for: Monitoring and managing clubroot, caused by Plasmodiophora Brassicae (Woronin), on canola (Brassica napus) in Ontario, Canada

Resting spores of P. brassicae can persist in soil for years and new pathotypes rapidly overcome the resistance provided by single resistance genes. To monitor the disease in Ontario, clubbed roots from 12 fields were pathotyped; 11 were emergent, virulent pathotypes.

Soil pH above 7.2 effectively reduced clubroot severity in high organic matter soils, calcium alone had no effect. Microbial communities differed between bulk soil and the rhizoplane of healthy hosts and clubbed roots. Natural freeze-thaw temperature cycles overwinter as well as long-term storage in water reduced the viability of resting spores, but not enough to prevent high levels of disease on susceptible hosts.