Municipal officials across the province are increasingly on guard in the ongoing war to slow the relentless spread of clubroot.
It’s been 15 years since the pernicious soil-borne disease was first found in a canola field near Edmonton. The confirmed tally last year was 2,744 fields — but the true number is almost certainly higher.
Still, municipalities aren’t waving the white flag.
“As we find more clubroot, we increase the number of inspections. So on any given year, we can do between 80 to 200 inspections annually within the county,” said Dion Burlock, ag fieldman for Lacombe County, which has confirmed clubroot on 80 to 90 fields and inspects at least one field per township.
Once found, owners of the field are told no canola can be grown on them for two years, although county officials try to limit the hardship for producers, as canola is typically their most profitable crop by some distance.
“If it’s found in an area less than 40 acres, we may place a growing restriction on that 40 acres. It allows us some flexibility to deal with the severity of the problem,” said Burlock.
In nearby Red Deer County, a team of officials visually inspect fields and send suspect samples away for lab analysis.
“If it’s under five per cent infestation, we provide information to the landowner and talk to them about a management plan and kind of leave it at that, let them manage it on their own,” said Cody McIntosh, the county’s agriculture manager. “If the management has been too intensively in canola, then we try to back off with issuing a pest notice and restricting the growth of canola for a period of about three to four years.”
Clubroot has been confirmed in 25 to 35 fields in the county.
“We only inspect a sample of our canola fields, so we know there’s some around. We treat most of our canola fields as though it’s suspect or it’s there,” said McIntosh. “We continue our education process, we talk to as many landowners as we can, and we want everyone aware of clubroot and how to manage for the disease because it’s present and it’s here.”
The County of St. Paul has a zero-tolerance policy for clubroot.
“We check every field for clubroot when it first flowers,” said Keith Kornelsen, ag fieldman for St. Paul. “If we find something that looks like clubroot, we’ll just pull about 25 plants at the entrance to the field.”
If any plants look suspect, they’re sent to the lab for analysis. If confirmed, the farmer is contacted and a pest notice is issued. The pest notice states no canola can be grown for three years and after that, it must be a resistant variety.
“We check all the fields. I think we miss a few fields because they’re hidden. We check over 600 fields a year, so we get most of them,” said Kornelsen. “We’ve had under 40 fields confirmed with clubroot.”
The different approaches stem from the fact that enforcement of the Agricultural Pests Act (which has covered clubroot since 2007) falls to municipalities and “everyone is handling it a little bit differently,” said Burlock.
Even in St. Paul — which last year sprayed down two quarters of canola after one producer grew the crop after being ordered not to — puts the emphasis on persuasion.
“We’re very open to discussing the issue with farmers and letting them know about the seriousness of it before it gets terrible,” said Kornelsen. “We try to have as much communication as possible to show that we’re not just making this up.”
Municipalities in Peace Country have banded together to form a common front after the region lost its clubroot-free status when the disease was found in Big Lakes County last year. Thirteen agriculture service boards from the municipalities have got together to establish some guidelines, said Sebastien Dutrisac, ag fieldman for North Sunrise County and vice-president of the Association of Agriculture Fieldmen.
“This gives us a bit more of a strong approach and a collaborative approach because when we talk to the producers, they know that 13 municipalities got together and they decided that this should be the best way to manage it, he said. “It gives them a little bit more of a backing and it’s not just a local issue. It’s a regional issue.”
Northern Sunrise County also has a zero-tolerance policy. As soon as it is found, a notice is issued and canola isn’t allowed to be grown on the field for four years. If the level of infestation is low, the county won’t issue a formal notice, but the producer must still agree not to grow cruciferous plants for four years.
“If they go back into a canola field and don’t respect the agreement, we will destroy the crop,” said Dutrisac. “That’s difficult to deliver as an inspector, but we’re trying to have a collaborative approach. We’re all in this together.”
Producers are concerned after clubroot was confirmed in two counties.
“The fact that they’re asking questions is a good thing, because they can take a proactive approach instead of a reactive one,” said Dutrisac. “It gives us a chance to promote better management practices as well as the Alberta Clubroot Management Plan.”
Growing resistant varieties is a cornerstone of that plan (which can be found by googling its name), but it’s not enough by itself.
At an Alberta Canola conference this winter, University of Alberta plant pathologist Stephen Strelkov — one of the world’s leading clubroot experts — said a failure to practise good stewardship of resistant varieties has led to new virulent strains. As of last year, more than 100 fields with new strains that defeated resistance had been confirmed in Alberta, Streklov said.
“Resistance is vulnerable, and we need proper resistance stewardship,” he told conference attendees.
That stewardship centres on having longer rotations as well as rotating resistant varieties, so the same resistance gene isn’t being used all the time.
Researchers are also trying to develop additional management tools, such as the use of liming (which lowers pH and may be able to keep clubroot in check if it is discovered early and spore numbers are relatively low).
Farmers are also being urged to consider limited use of fumigants. Although expensive, using them around field entrances could reduce the odds of a vehicle or piece of equipment picking up spore-infested soil.