BROOKS, Alta. — Consider the Smartie.


A piece of soil the same size as the candy could harbour up to a billion clubroot spores. 


Next, consider how much dirt comes off a piece of farm equipment, and the potential to spread the costly disease increases exponential.


Cleaning equipment should be standard practice, but it has been a hard sell among many farmers, said Ron Howard, who recently retired from Alberta Agriculture. 


“There was quite a bit of resistance among producers and there still is,” he said at a canola education day held at the provincial Crop Development Centre near Brooks July 31. 


Cereal and oilseed producers use big equipment over large areas, but too often sanitization is ignored. 


“We had from the beginning a big uphill battle with producers that sanitization was something they had to consider,” he said.


The petroleum industry was accused of introducing clubroot onto farmland with their equipment, but research has shown the highest incidents were at field entrances with dirty equipment such as tractors, cultivators and combines.


For example, one study showed a 40 foot cultivator carried 100 pounds of soil while a large four-wheel drive tractor can carry 300 to 400 lb. of soil. 


“It was more than enough soil to carry clubroot from one field to another,” he said. 


Combines carry dust, straw and seeds, in which spores have been found.


“Seed and straw of any crop you chose to grow in a clubroot infested field could have clubroot spores,” he said. 


Sanitization involves a three step process:


• In the rough clean, dirt is scraped off using a scraper pressure washer. A tarp is placed underneath and then bundled. The soil is put back where it came from.

• The next step is using a pressure washer.

• The final step is spraying a disinfectant containing compounds such as peroxide, acetic acid or industrial bleach. 


The equipment needs to stay wet for 20 to 30 minutes so the disinfectant can do its job because the spores are hard to kill. 


Do not hose the disinfectant over dirty equipment because it will not penetrate well enough to do the job. There is no need to use so much disinfection that it is flowing on the ground.


Researchers have tested a concentrated acetic acid used in organic agriculture and found it to be highly effective on clubroot spores.


Cleaning should be done on gravel or a grassy spot to prevent too much mud from spreading in the area. 


Foot mats with disinfectant or wire brushes to clean shoes are also recommended. 


Biosecurity is not just for clubroot but other potential diseases such as fusarium head blight, weed seeds, insects and nematodes. 


The Canadian Food Inspection Agency has developed a biosecurity program, and grants may be available to buy sanitization equipment.