The disease continues its relentless spread across Alberta — but the risk has become more manageable
John Guelly felt as though he had been diagnosed with a terminal illness when he found clubroot in his canola fields nearly 10 years ago.
But in the decade since then, the Westlock-area farmer has come to view the disease as more of a chronic condition — still risky, still potentially devastating, but ultimately manageable with just a little work.
“It was initially quite the shock to the system — you’re worried about whether you’re going to be able to continue to farm,” said Guelly.
“But the more you learn about it, the more you learn how to cope. Now it’s probably not in my top three things that I worry about anymore.”
Over the last decade, the understanding of how to manage clubroot effectively has advanced, as have clubroot-resistant genetics. And with that has come a shift in mentality.
“Like anything, it’s a matter of finding out more information about it — what sort of things you can do to reduce your spore load and find a new way to farm, in some senses,” said Guelly.
“A lot of it is just a matter of doing a few extra things and being a little more careful to make sure you’re not spreading it around.
“It’s not something you can completely forget about — you’ve got to keep it on your radar — but it’s certainly not as big an issue as I was initially worried it would be.”
Joining the ‘clubroot club’
“I’m finding that a lot of the people who were at some of those speaking engagements are calling me now and saying, ‘I just joined the clubroot club. What do I do?’” he said, adding the number of calls he received increased last summer.
“In a lot of cases, I just talk them off the wall, and then put them in touch with the right people and the right information so they can try and deal with the disease.”
But although clubroot has become more manageable, it has continued its seemingly inevitable spread across Alberta, despite measures taken to prevent that.
“With everything we’ve tried to do to reduce the spread, maybe we’ve slowed it down a little bit, but it still seems to be spreading pretty rapidly,” said Guelly.
As of last year, clubroot had been confirmed in over 3,300 fields in Western Canada.
“I hate to speculate, but I think it’s fair to say that we will see more clubroot in the next five years,” said Angela Brackenreed, agronomy specialist with the Canola Council of Canada. “To what degree will we see it spread in the next five years? That really depends on how effectively we can continue to utilize the genetic resources that we have and the integrated pest management strategies that we know work.”
But the fact is clubroot can spread easily and rapidly.
“It’s a really tough one to stop in its tracks. Anything that moves soil can move this disease,” said Brackenreed. “Because of the nature of this pathogen and the mechanism of its spread, it has certainly grown in severity and concentration, but we are really fortunate to have a lot of resources being put behind this disease through agronomic management, resistance, and breeding.
“I’m confident that we’ll continue to see more advances in that area in the coming years.”
Guelly agrees.
“It’s not something we can eradicate. The best we can do is try to keep the spore loads low.”
‘Everyone is making the switch’
That’s changed as seed companies shifted production primarily to resistant varieties — there are now more than 50 available in Alberta.
“I think the bulk of people are using that on their farm now, and it’s one of the easiest things they can do to try to reduce their risk,” said Guelly.
“That’s a great thing in my mind. I look at that and have to smile, seeing that everyone is making that switch. It’s one of the easiest things to do, and I’m glad that they’re grabbing the low-hanging fruit.”
Growers should be switching to resistant varieties as early as they can, even in the areas of Alberta where clubroot hasn’t yet been detected, said Brackenreed.
“We have growers who are able to grow pretty exceptional crops even in the face of clubroot with this resistance available to them,” she added.
“We’ve seen just an amazing amount of genetic resistance come on the marketplace in recent years, and that will certainly help us to slow down the spread of this disease.”
However, relying too heavily on genetic resistance hastens the day it breaks down, so other management strategies also need to be used, she said.
For Guelly, the change that has had the biggest impact was extending his rotation.
“We were in a two-year rotation for probably 15 years, and we know now that the bulk of the spores die within the first three years,” he said. “If you can stretch that two-year rotation into a three-year rotation, that’s one of the biggest things you can do.”
That two-year break between host crops — including weeds such as volunteer canola — can reduce spore levels by 90 per cent, said Brackenreed.
“We talk about rotation a lot, and sometimes it seems like producers are still asking, ‘Is this really going to be effective for me?’” she said. “But we know it can be extremely effective if we’re utilizing rotation and managing host weeds.”
Scouting diligently is also key, she said.
“The longer that this goes undetected in a field, the more it’s going to spread throughout the field and to other fields on your farm.”
Sooner is always better, added Guelly.
“It’s a lot like other human diseases — the sooner you find it, the sooner you can start changing your practices while the spore load is low,” he said. “You can continue to grow canola with a healthy rotation if you have low spore loads.
“But if you wait too long and the spore loads get too high, you’ve got to take more drastic measures.”
Another way to keep spore loads low is by limiting soil movement by reducing tillage and sanitizing equipment.
How that looks on a farm depends on the farmer and the circumstances — but pressure washing every piece of equipment every time when exiting a field is not something you’ll see in the real world.
“Ideally we would go through all of the steps of biosecurity and we would reduce our risk by almost 100 per cent,” said Brackenreed. “We know that this is effective. We know that it works. But it is incredibly time consuming and potentially not practical in some circumstances.
“So I think we need to look at it as how can we be strategic about our biosecurity rather than looking at it as an all or nothing.”
Guelly has started doing a rough clean of his equipment between fields, saving his ‘hot fields’ for last so that he can more thoroughly sanitize the equipment once they’re done.
“I’m not saying we’re getting out and spraying with bleach between every field or anything,” he said. “I’ll stop when the field’s done and knock off the bulk of the dirt clumps that are on the equipment, and that gets rid of the bulk of any spores that you’re going to move from place to place.”
Something like that is “more reasonable and more realistic,” added Brackenreed.
“Even just removing the visible big clumps of soil can reduce the amount you’re moving by over 90 per cent. That’s huge.”
Even so, none of these management strategies are a “magic wand that will get it out of the soil.”
“Once it’s there, we have to deal with it being there, and it’s a constant hamster wheel trying to stay on top of it,” said Brackenreed.
“So it’s really important in an effort to keep these spore levels low and local that we deploy genetic resistance early — that we don’t delay in the use of that tool — and that we take seriously these other integrated pest management techniques that we know work.
“They won’t work magic immediately, but when we look at them through a longer-term lens, they are effective.”
But the real key to managing clubroot is spotting it early — and remembering that finding clubroot doesn’t have to be a death sentence for your canola crop.
“If you do find it, it’s not the end of the world,” said Guelly. “You’ve got to change a few things that you’re doing on your farm, but it’s not going to end your farming career.”
