Crucifer Diseases: Clubroot (Plasmodiophora brassicae)
Damage Symptoms: Most crucifer crops are susceptible to clubroot; cabbage, Chinese cabbage, and Brussels sprouts are highly susceptible. Enlargement of fine roots, secondary roots, and the taproot results in the formation of spindle-shaped clubs. The clubs are generally widest in the middle and taper toward the ends. Severely clubbed root systems are impaired and cannot efficiently absorb water and nutrients; therefore the plants are stunted and may wilt with only slight water stress. Lower levels frequently turn yellow in advance stages of disease development.