2009 Clubroot Inspection Program
Disclosing clubroot information

Further information
Transportation and Agriculture Services
780-417-7100 (24 hours)
Ag Info Centre
780-310-FARM (3276)
Clubroot is a serious soil-borne disease that infects the roots of cruciferous crops. The crucifer family includes field crops such as canola and mustard as well as vegetable crops like cabbage, broccoli and cauliflower. Clubroot has the potential to be a significant threat to canola production in parts of Alberta.
 
Clubroot is not a new disease in Canada or Alberta. The first report of clubroot in western Canada was confirmed in 2003 near Edmonton, Alberta. In 2005, clubroot was identified in Strathcona County.
 
The clubroot pathogen is able to persist in the soil for many years. The spores have a half-life of about four years, but are able to survive in the soil for up to 20 years.  The resting spores are able to exist without a host present. Research has shown that fields with 100 percent infestation will have a yield reduction of 50 percent. Infestations of only 10 to 20 percent will still have a five to 10 percent yield loss.
 
Managing clubroot after establishment in a canola field is difficult. There are no known clubroot resistant canola varieties in Canada. Currently, there are no registered crop protection products in Canada to control clubroot.

Photograph of clubroot

A declared pest
In 2007, Alberta Agriculture and Food declared clubroot a pest by the Pest and Nuisance Control Regulation under the Alberta Agricultural Pests Act and released the Alberta Clubroot Management Plan.
 
The Alberta Agriculture Pest Act gives the municipal authority responsibility to enforce pest control measures within their jurisdiction. The landowner or occupant is responsible for preventing the disease from being present in their fields.
 
How can we help?
A proactive inspection program allows Strathcona County to provide timely education and promotion of best management practices to minimize further spread of the disease. All canola fields and fields found with volunteer canola will be inspected for clubroot. Fields known to have clubroot from previous years will be inspected to ensure that canola is not being grown. Inspections will take place from the beginning of July to the end of September.
 

Photograph of clubroot

What does it look like?
Galls appear on the roots of infected plants, ranging from tiny nodules to large, club-shaped outgrowths that may involve most of the root system. At first, galls are firm and white but become soft and greyish-brown as they mature and decay. Severely infected roots cannot absorb enough water and nutrients to properly nourish stems and leaves. The plant growth is stunted and wilting occurs due to moisture stress. At the end of the growing season, the galls break down into the soil releasing new spores.
 
The symptoms of clubroot will vary with the growth stage the crop is at when infection occurs.
  • Early infection at the seedling stage can result in wilting, stunting and yellowing of canola plants in the late rosette to early podding stage.
  • Infection that occurs at later crop stages may not show plant wilting, stunting or yellowing. Infected plants will ripen prematurely and seeds will shrivel.

Photograph of clubroot

Clubroot prevention
Since clubroot infestations are still in isolated locations in Alberta, producers should take precautionary measures to curb the spread of this disease. Growers should be vigilant to prevent the introduction of clubroot to clean fields because few economic options exist to control infestations in canola.
 
Recommended preventative measures include the following:
  • Scout canola fields regularly and carefully. Identify causes of wilting, stunting, yellowing and premature ripening. Pull out wilted plants to diagnose gall formation on roots.
  • Practice meticulous sanitation to prevent and restrict the spread of contaminated material. Clean soil and crop debris from field equipment before leaving or entering fields.
  • Practice soil conservation to reduce erosion. Resting spores move readily in dirt transported by wind or water erosion and by overland water flow. They are not spread by air.
  • Avoid the use of straw bales and manure from infested or suspicious areas. Clubroot spores are reported to survive through the digestive tracts of livestock.
  • Avoid common, untreated seed (including canola, cereals and pulses).
  • Implement long rotations. Canola, mustard, kale and cole crops should be grown no more than once in a five year rotation. Although crop rotations won't prevent the introduction of clubroot to clean fields, it will restrict disease development within the field and control the infestation.
  • Volunteer canola and susceptible weeds (mustard family, dock and hoary cress) must be controlled in rotation crops. A few non-cruciferous crops are hosts including orchard grass, red clover, perennial ryegrass and red-top or creeping bentgrass.
Clubroot: a disease of canola and vegetablesPresentations
Clubroot: A Disease of Canola and Vegetables
Held on March 10, 2008 at Partridge Hall Community Hall
  Last updated: September 28, 2009

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