Reducing Clubroot Risks Associated with Field Research

Because clubroot is not widespread in Manitoba, plot research looking at clubroot (Plasmodiophora brassicae) as the target pest may only be conducted in locations outside of Manitoba (ex: established field nurseries in Alberta or Ontario/Quebec). 

Operational Guidelines for Conducting Field Research

Because of the risk that clubroot is already present in Manitoba soils, caution must be taken in canola field research, even when clubroot is not the disease of interest.
The following guidelines are recommended for all field research, co-op variety testing and post-registration variety testing conducted in Manitoba.
  1.  Industry personnel should speak with the grower if clubroot is known or suspected to be present in the field or surrounding area.
  2. As part of the risk assessment, discuss with the grower the type of field practices (rotations, custom field operators, oilfield activities, etc.), which potentially increase the chance of spreading clubroot. In addition, ask about past crops and weeds, noting those in the Brassica family are susceptible to clubroot.
  3. Inform the grower of the precautionary measures being taken to prevent clubroot spread. Ask the grower if he requires any additional measures and what those should be. Growers should feel encouraged to inspect industry equipment and protocols to be satisfied that there is no risk of contaminating their land. If tours are to be conducted, then establish clearly what precautions will be implemented.
  4. Industry personnel should discuss with growers the implications of their privacy policy and corporate responsibility in regards to clubroot findings. 
  5. Fields selected for trials should be sampled prior to planting to determine if clubroot is present, as well as every year.  If a susceptible crop is grown, watch for clubroot symptoms. Land in proximity to the field entrance and/or the plot area should be sampled in a ‘W’ pattern providing 5 samples, which can be submitted as a composite.  Sampling canola volunteers/Brassica weeds should ideally be done in the year prior to the trials, if the potential plot location is known.
    • If clubroot is detected above 10,000 spores/gram soil by PCR test or other identifiable means (infected crops or weeds), these fields will not be utilised for research. The grower must be informed of the findings.
    • If clubroot is discovered at the site while the site is in use (ex. on plants in plots), use of field equipment needs to be minimized, and any such equipment must follow vehicle sanitation procedures. The grower must be informed of the findings.
  6. Trucks, trailers, etc. should be parked or unloaded off-site. Any fields known to have clubroot infestation will be off-limits to any vehicle access and will be strongly avoided for foot-traffic as well.
  7. Records should be kept of all fields visited and sanitation procedures followed.

Vehicle Sanitation Procedures

  1. The most clearly established factor contributing to clubroot spread was found to be from contaminated soil on agricultural equipment. Do not drive into field or access, but park on the road whenever possible.
    • Exceptions can be made for field-trials with permission of the grower. In these cases vehicle sanitation procedures will apply.  Industry personnel can walk into fields but must follow human sanitation procedures. 
  2. Vehicles should especially stay out any of these fields following a rain – wet soil is much more difficult to remove than dry.
  3. Before entering any field, vehicles and equipment must be clean. Growers should be encouraged to inspect any vehicles/equipment as well. This will reduce concern that soil (infested or not) is being transported.
    • When leaving the field, knock off all clumps of soil in field before leaving field – preferably not in the field’s approach, but off to one side.
    • If a pressure washer is available, pressure wash any visible soil, focus on tires, undercarriage, and any other parts that may have contact with soil. If this is not available, use a carwash and clean vehicle and equipment as best as possible.
    • Mist down tires and other points of contact with a disinfectant. This disinfectant process should be the last step, since most disinfectants do not effectively penetrate soil. The disinfectant will need to be in contact for 15 to 20 minutes with the pathogen to be effective. Vehicles and equipment need to be clean and free of soil for the disinfectant process to be effective.

Human Sanitation Procedures

  1. If industry personnel enter a field, whether it is known to have clubroot or not, they are to follow these human sanitation procedures:
    • Wear disposable footwear that can be removed immediately after leaving the field. Another option is to use rubber boots or other footwear that can be sterilized (misted) with a disinfectant solution upon leaving the field.
    • Dispose of the disposable footwear in a sterile fashion. Sealing in a garbage bag and burning is preferred. Do not reuse disposable footwear.
    • Clean and disinfect any tools that may have been in contact with soil in the field

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