In an effort to greater our defences against the rampant spread of clubroot, the County of Two Hills, along with five other municipalities have increased their efforts of detecting Clubroot by implementing an enhanced clubroot surveilance program. The municipalities have been using Burkard spore traps, which essentially use adhesive tape to trap spores for testing. The traps were set up for four weeks during the summer and submitted to the University of Alberta for subsequent testing. Hannah Musterer, agricultural services technician with the County of Vermilion River, said in an interview, “As clubroot evolves as a soil-borne disease in Alberta, we are monitoring it more because counties and MDs enforce the pest act. In order to enforce it, we have to find it so we’re doing more inspections.” Best Management Practices: 1. Use clubroot-resistant varieties when growing canola in areas where the disease is established. Alternate growing clubroot-resistant varieties with different sources of resistance when they become available. 2. Although crop rotation will not prevent introduction of clubroot to clean fields, the practice will lower subsequent disease buildup and severity and reduce other diseases, such as blackleg. Crop rotation will not eradicate the clubroot pathogen from the soil. A minimum of a 2-year break from all clubroot-susceptible hosts is recommended for all producers. A longer break may be required if clubroot is well-established, or a Notice to Control is issued by the local authority. Canola growers in high-risk situations (confirmed clubroot in the field or area) should follow traditional canola rotation recommendations (one canola crop every 4 years) using clubroot resistant varieties. The one- in 4-year rotation recommendation using resistant varieties is designed to slow down pathogen population shifts. There have been numerous reports in Alberta of pathogen population shifts to a strains not controlled by clubroot-resistant canola. This has occurred many times in other parts of the world in canola and cole crops. 3. Growing a clubroot-resistant variety in fields without known clubroot but in areas where the disease is prevalent can help slow the establishment of the disease. Since there would be low spore numbers when clubroot does get introduced to the field, this approach should not significantly induce changes in the strains to those that are not controlled by the variety resistance. The greatest pressure to alter the pathogen strains is frequent exposure (rotation length) of the same resistance to high soil spore populations (distinct clubroot patches have occurred in the field). 4. Volunteer canola and cruciferous weeds must be controlled in infested fields to prevent more than 3 weeks of growth, to avoid the production of new resting spores on these host plants. 5. Practice good sanitation (cleaning and disinfection) of machinery and equipment to restrict the movement of potentially contaminated soil. This approach will also help reduce the spread of other diseases, insects and weed seeds. Resting spores can be spread via contaminated soil. Moderate to high infestations will leave high spore concentrations in soil on field machinery, thus sanitation is very important in these situations. All producers should follow the practice of cleaning soil and crop debris from field equipment before transport from all fields. The most critical step in cleaning equipment is physical dirt removal – knocking or scraping off soil lumps and sweeping off loose soil. • For risk-averse producers or with heavy infestations, there are additional cleaning steps, with diminishing returns on investment, that will slightly decrease the risk of spread, but will involve considerably more work and expense: •After removal of soil lumps, wash equipment with a power washer, finish by misting equipment with disinfectant. Recommended products include 2% active ingredient bleach solution, Spray Nine, Adhere, Premise and AES 2500. The use of a disinfectant without first removing soil is not recommended because soil inactivates most disinfectants. A 20 to 30-minute wet period is recommended for good efficacy. For more information on disinfecting equipment for clubroot prevention see the fact sheet Preventing Clubroot: Agricultural Sanitization. • Disinfectant footbaths can be an effective first line of defence in a biosecurity program. However, footbaths are not able to completely eliminate biosecurity risks in all situations. Disposable foot coverings should be utilized where possible and in combination with a foot bath to more fully minimize biosecurity risks associated with soil-borne diseases like clubroot. For more information on how to develop a comprehensive biosecurity plan for a farm or business, see the Canadian Food Inspection Agency’s National Voluntary Farm-Level Biosecurity Standard for the Grains and Oilseeds Industry. 6. Seed and establish an area with grass near the field exit. A well-sodded grass will retain soil removed during equipment cleaning without creating a mud hole after washing and thus will reduce the re-introduction of infested mud to wheels when moving from this area to the exit. The grass area will not be susceptible to clubroot if volunteer canola and mustard weed species are controlled. 7. Use direct seeding and other soil conservation practices to reduce erosion. Resting spores can also readily move in soil transported by wind or water erosion. Reducing the amount of tillage on any given field will reduce the spread of the organism within the field and to other fields. 8. Minimize vehicle and equipment traffic to and from fields. 9. In situations where fields are lightly infested only near the current access, create a new exit at another distant edge of the field if possible. 10. Scout canola fields regularly and carefully. Identify causes of wilting, stunting, yellowing and premature ripening – do not assume anything! 11. Avoid the use of straw, hay or greenfeed, silage and manure from infested or suspicious areas. Clubroot spores may survive through the digestive tracts of livestock. 12. Avoid common untreated seed (including canola, cereals and pulses). Earth tag on seed from infested fields could introduce resting spores to clean fields. The effect of current seed treatment fungicides on resting spore viability on seed is currently being studied.