How to Manage Pests

Pests in Gardens and Landscapes

Seasonal development and life cycle—Clubroot

Clubroot infects all of the cole crops, alyssum, nasturtium, as well as many weeds in the mustard family. The fungus persists in soil for many years. Infection is favored by acid soils with adequate moisture, but infections can occur above pH 7.0. In the presence of host plant roots, spores germinate and release swimming spores, called zoospores. These zoospores infect and colonize root hairs. Later, a second type of zoospore appears that can infect the main roots. Infection and colonization by this second zoospore causes the galling and clubbing of roots. Additional spores are formed inside the galled roots and are released into the soil when roots decay. The fungus is dispersed by the movement of infected plants, especially transplants, and the movement of soil.

Plants infected with clubroot are stunted
Plants infected with clubroot are stunted

Infected plants show root clubbing
Infected plants show root clubbing


Statewide IPM Program, Agriculture and Natural Resources, University of California
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