Sask. Clubroot Strategy Paying Off

Wednesday, April 23, 2025

Survey Shows No New Cases, But Long-Term Effort is Still Needed

By Matt Jones

Farmers in Saskatchewan were no doubt happy to see the recent announcement that no new clubroot cases had been discovered in the province in 2024. The announcement came from the provincial government, and was based on a survey conducted by SaskOilseeds. There are 82 fields with confirmed visible symptoms in the province since 2008. Two additional fields were found with the clubroot pathogen DNA in the soil, for a total of 45, but had not yet developed the disease.

“Clubroot is a potentially quite devastating plant disease here in Saskatchewan; we’ve seen it at high levels, but relatively speaking, not quite as bad as our neighbours in Alberta,” says Kaeley Kindrachuk, an agronomy extension specialist with SaskOilseeds.

“Clubroot can last within the soil for up to 20 years. So we have to really consider crop rotation and using resistant varieties as tools, rather than relying completely on them to help us with this disease.”

The impacts of clubroot can vary depending on the level of the disease, says Kindrachuk. The clubroot pathogen can lead to the development of ‘galls’ on plants – swollen root tissue. Those roots will eventually disintegrate, resulting in spores being released into the soil.

“Those galls can restrict the ability of the plants to obtain water and nutrients from the soil,” says Saskatchewan provincial plant disease specialist Alireza Akhavan.

“That’s quite significant, and producers are quite concerned about this disease in Saskatchewan. The pathogen was first detected in 2008, and then there were two research sites that had the disease in 2011, and then for a second time it was found in soil in 2012, and since 2017 it has continuously been found every year. Now we have 82 fields with visible symptoms documented and confirmed.”

Akhavan notes that Saskatchewan has 296 rural municipalities (RM) – and 30 of them now have a record of clubroot with visible symptoms, and 22 have had the pathogen detected. The two new fields that were found with the pathogen in 2024 were both in the same RM.

As significant as the impacts can be – recent studies have indicated that increases in the disease severity index for clubroot lead to a directly comparable decline in yield – Akhavan cannot recall any farm businesses in the province that were driven out of business due to clubroot impacts.

“In Saskatchewan, after we realized the pathogen occurrence in neighbouring provinces, we moved quite quickly and implemented the monitoring program and tried to raise awareness,” says Akhavan.

“We tried to raise awareness not only regarding clubroot as a disease, but also the biosecurity measures applicable to it. So overall, the province is in good shape.”

“Our producers are knowledgeable,” continues Akhavan. “So they have all the management toolboxes in place, and they use them, and things are quite in control. The disease can cause significant yield loss, up to 50 per cent or greater under high disease pressure. But I don’t think that any field or any business got so much damage to go out of business. I am quite sure that there was no such case in Saskatchewan.”

Among those management tools is crop rotation. The pathogen has ‘ultimate viability’ – the ability for the spores to survive in the soil for up to 20 years – but that is tempered by pathogen decline. Two years away from canola cultivation decreases the pathogen population by 90 per cent.

“So, given the number of spores per gram of the soil, we can help producers to assess the need for rotation length, but overall the recommendation is that they need a break from canola for two years,” says Akhavan. “If a field has the clubroot pathogen in their soil, a break from canola will help not let the pathogen get to that 1,000 spores per gram in the soil, which is the threshold to cause symptoms. Biosecurity is also very important. If the field is already infected, it is very important not to further spread it within the field.”

Kindrachuk says the surveys have shown a decline in clubroot pathogen in the last two or three years. She attributes this trend to a variety of factors.

“It’s been drier,” says Kindrachuk. “That may not help our case with some other diseases, but with clubroot, it does. But also, the awareness piece with producers. I think farmers are watching a bit more carefully. They’re rotating the canola varieties, they’re rotating their canola crops, so that they’ve got a decent crop rotation. I think we’re on the right track here in Saskatchewan.”

She does not, however, attribute the decline to any particular techniques or technology. There haven’t been any significant new treatment or management options developed for clubroot that have driven those results.

“We have some different management options, and those are all available to growers,” says Kindrachuk. “It’ll depend on the level of clubroot that is found. Sometimes we just need to rotate to different clubroot-resistant varieties. Sometimes we need to take a certain piece out of production. Sometimes, we’ve got to find a different entrance to the field. It’s all very dependent on how much clubroot is actually there.”

The extensive clubroot monitoring program in Saskatchewan launched in 2018. In 2024, they conducted their clubroot risk-based survey, as well as a general canola disease survey, and followed up on previously infected clubroot fields and conducted an on-farm testing program. All of these efforts are conducted with the permissions of the farmers on roughly 500 fields.

“The on-farm testing program is what SaskOilseeds administers with support from the Ministry of Agriculture and the SARM (Saskatchewan Association of Rural Municipalities) technical advisor,” says Kindrachuk. “It’s paid for by SaskOilseeds. Producers can call in or go to their local Ministry of Agriculture office or their local RM office that would participate, and they get a soil test bag with all the instructions on how to submit a soil sample to the lab for confirmation of pathogen DNA.”

Asked whether farmers in Canada may ever be totally free of clubroot, Kindrachuk theorizes that we may never be fully rid of it. But we are making good steps.

“We’ve had research going on for quite a while, but the thing with research is it doesn’t happen overnight. It takes time. We need to be sure – the researchers are doing a fantastic job, but we can’t slow down our efforts as farmers and agronomists. We need to be paying attention to what’s happening in our fields, regardless of if we have something that would be a silver bullet or not.”

Kindrachuk asks any farmers who have positive findings to report them to the Ministry of Agriculture to help keep their map up to date.

“If visual root gall symptoms are found on plants and they’re reported to the ministry, they can be sent for clubroot pathotyping to Stephen Strelkov at the University of Alberta,” says Kindrachuk. “And that is a cost that’s covered by SaskOilseeds. Currently in Saskatchewan, we haven’t found any pathotypes that are breaking resistance. That’s a great thing, but this pathotyping does help to know where we’re at.” BF