Clubroot remains one of the important diseases affecting members of the mustard, or Cruciferae, family. The disease occurs worldwide and affects such important crops as cabbage, cauliflower, brussels sprouts, broccoli, and Chinese cabbage. Every effort should be made to keep contaminated crucifer transplants from entering a farming operation because the pathogen survives for many years even in the absence of host crops. Clubroot can cause drastic yield reduction and occasionally total losses in crucifers.