Assume clubroot is in Saskatchewan, ‘we just don’t know about it,’ says expert
PRINCE ALBERT, Sask. — The best way to fight clubroot is to prevent the spores from building up in the first place, says Clinton Jurke from the Canola Council of Canada.
“Don’t assume this is an Alberta problem,” Jurke told the Disease and Weed Spray Clinic in Prince Albert June 26.
“Make the assumption that the disease is nearby, if not in one of your fields, and to start scouting for it.”
Saskatchewan and Manitoba are in the position Alberta was in a decade ago, when only a handful of the province’s fields were infected with clubroot.
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Thousands of Alberta fields are now infected with the disease.
Jurke said some producers in areas where clubroot has not been found question if they should use clubroot resistant varieties.
Resistance in these varieties holds up for as little as two crop cycles, and producers are afraid of needlessly providing opportunities for the resistance to break down.
Jurke said Manitoba and Sask-atchewan fields infected with clubroot often have 1,000 to 10,000 spores in a gram of soil, compared to some of the highly infected Alberta fields that have more than a billion clubroot spores in a gram of soil.
“There is a million times more spores in infected Alberta fields than in infected Saskatchewan fields, so there is a million times more opportunity for that pathogen to overcome resistance,” Jurke said.
“So what this means is that if we start using resistant varieties in Saskatchewan now, the risk of that happening is going to be a lot lower than in the Edmonton region.”
A 2013 clubroot survey tested more than 100 Saskatchewan fields, and all were negative.
“But that doesn’t mean there isn’t more clubroot out there,” Jurke said.
“I think anyone that is sensible would assume that Saskatchewan does have clubroot in multiple locations, we just don’t know about it.”
The pathogen has been found in four Saskatchewan rural municipalities: St. Louis, Aberdeen, Bigger and an unidentified RM.
“Do the things the Albertans didn’t do,” Jurke said.
“Look for the disease, start sanitizing equipment and start using resistant varieties to help keep those spore concentrations down to a minimum.”
All the available clubroot resistant varieties are susceptible to the new pathology that has developed in Alberta.
Jurke said tight rotations have hastened the resistance breakdown.
The projection when the resistant varieties were introduced in 2009 was that their clubroot resistance would hold up for only two growing cycles.
“Most of the growers are on a two-year rotation, so that brings us to 2013, and that’s precisely what’s happened,” Jurke said.
“It would have been really great if we could have been talking about this in 2017 if guys were on a four-year rotation, but a two-year rotation put enough pressure on that resistance to fail.”
