DAUPHIN, Man. — For years, plant pathologists and agronomists have told prairie farmers to thoroughly wash and sanitize tractors, cultivators and seeders between fields to stop the spread of clubroot.
That isn’t happening so the Canola Council of Canada is taking a different approach. Washing and sanitation is still a recommendation, but it’s no longer a point of emphasis for clubroot management.
“It works. Absolutely it works. But realistically it’s not going to happen,” said Dan Orchard, the council’s agronomist in central and northern Alberta, who spoke at a Canolab agronomy workshop held March 15-16 in Dauphin, Man.
“The message of cleaning your equipment and scraping off every gram of soil was not the right message. We didn’t understand that that’s just not feasible…. You can talk about it all you want but it’s not going to be employed because it’s not really realistic.”
Clubroot is a soil-borne disease in canola that causes galls to form on the roots.
The disease is endemic in central Alberta, but farmers in the region continue to grow canola thanks to clubroot resistant varieties.
The disease spreads through transport of soil from field to field, primarily on the wheels of tractors and other agricultural equipment.
Orchard, who spoke about clubroot inside a hockey locker room at the Dauphin arena, said growers are willing to spend 10 minutes and knock large clumps of soil from seeders and tractor tires. But taking a few hours or more to wash isn’t viable because producers don’t have time, particularly at seeding.
A canola council pamphlet on clubroot, available in Dauphin, barely mentioned washing or sanitizing equipment.
It recommended the following four steps:
- using resistant canola varieties
- lengthening crop rotation if spore counts are sufficiently low
- reducing tillage or zero tillage practices
- scraping and sweeping a tractor frame after tillage
Orchard said there’s a good reason why cleaning and sanitization is lower on the list for clubroot management.
“Rather than putting it up high (on the list) because they (growers) quit reading once they get to something they can’t do,” he said.
“The lower we put it on the list, the better chance they’ll do the things above it on the list.”
An Alberta Agriculture website on clubroot has a similar message. It says producers should knock and scrape off loose soil between fields.
“The following additional cleaning steps may provide some extra benefit but involve considerably more work and expense: after removal of soil lumps, wash off equipment with a power washer. Finish by misting equipment with weak disinfectant.”
Renn Breitkreuz, vice-chair of the Alberta Canola Producers Commission, said some farmers are receptive to the washing message but others are reluctant to take the step.
“There are other ways (to control clubroot). Farmers kind of gravitate to using resistant varieties because that’s the easiest approach,” he said. “Lengthening one’s rotation is great tool to (reduce) spore load. And where it makes sense and will cause a real reduction, the cleaning and sanitation of course is important as well.”
Breitkreuz has clubroot on his farm in Lac Ste Anne County west of Edmonton, but only on a couple of fields.
He seeds those fields last, so soil isn’t moved from those fields to other parts of his farm. He also has knocked loose dirt from tractor tires and the openers of the seeder when moving between fields.
“After the season, I clean the drill and tractor thoroughly and then park it,” he said. “And I’m trying to lengthen the rotation on those fields and the whole farm.”
Cleaning and sanitation is an important tool but growers will decide what’s right for their farm, Breitkreuz said.
“It is a soil borne disease and doing what we can to mitigate that is important,” he said. “(But) you can do everything right and spring runoff, or the flipside on a dry spring with blowing soil … it can still move (the disease) around.”