Extension Logo
Extension Logo
University of Minnesota Extension
extension.umn.edu

Clubroot

Quick facts

  • Clubroot is a disease that affects plants in the cabbage family.
  • Plants infected by clubroot are stunted, wilt easily and may have yellowing leaves.
  • Roots of clubroot infected plants are swollen into thick, irregular club shapes.
  • Distribution of clubroot in Minnesota is unknown.
  • Infected plants should be composted or buried on site.

How to tell clubroot from other brassica issues

The base of a collard plant with a severely clubbed root system.
Severe clubroot infestation in collard greens
  • All members of the cabbage family (Brassicaceae) are susceptible to clubroot. This includes cabbage, cauliflower, broccoli, Brussels sprouts, kohlrabi, kale, radish, turnips, rutabaga, mustard greens, collard greens, arugula, bok choy and canola.
  • Plants are stunted or wilt with only slight drought stress. Leaves may turn yellow.
  • Young plants may be killed. Older plants fail to produce a harvestable head.
  • Roots are swollen and distorted into large clubs.
    • Clubbed roots are firm and light colored early in the season.
    • Smaller bulbous galls may be seen on secondary roots or coming off a large taproot like a turnip.
  • Secondary pathogens can infect clubbed roots, causing them to break down and turn black.
Four distorted and misshapen turnips laying on the soil.
Clubroot in turnips
Two rows of cabbage plants stunted due to clubroot.
Stunting due to clubroot

Biology

Soil-covered, swollen, club-like roots on pulled-out plants
Swollen, distorted roots caused by clubroot
  • Clubroot is caused by the fungus Plasmodiophora brassicae.
  • Clubroot is not seed borne, and most often enters new areas on infected transplants. It can also be brought in on improperly produced compost.
  • The fungus infects roots, which causes them to swell, giving the roots the clubbed experience that gives this disease its name. Infected roots cannot absorb water or nutrients.
  • Plants may be infected for a while before you begin to see symptoms above ground.
  • The pathogen forms thick-walled spores in infected roots.
  • Spores are released into the soil as roots break down and can survive for 20 years.
  • Spores can be moved on equipment and tools with clumps of dirt. They can also be moved short distances with strong wind on soil particles.
  • Spores become infective again when there is high soil moisture. Clubroot spores are more likely to infect plants in acidic soils (pH below 6.5).

Managing clubroot in the garden

 | 

Managing clubroot on farms

 | 

Authors: Marissa Schuh, horticulture IPM Extension educator, and Michelle Grabowski

Reviewed by Natalie Hoidal, Extension educator, local foods and vegetable crops

Reviewed in 2022

Share this page:
Page survey

© 2022 Regents of the University of Minnesota. All rights reserved. The University of Minnesota is an equal opportunity educator and employer.