Clubroot was confirmed in a field in Alberta’s Rocky View County last week, the first time the canola disease has been found in that county and one of few cases ever confirmed in the province’s south.
The soil-borne disease has been steadily expanding its territory since it was first identified in an Edmonton area canola field in 2003. In 2007, it was confirmed in fields within the County of Newell but after that no new sites were found in the south until 2017, again in Newell.
The Rocky View County discovery, southeast of Calgary, should put southern Alberta growers on greater alert, said Canola Council of Canada agronomy specialist Autumn Barnes.
“Hopefully growers can catch infestations before it gets as bad as this one in Rocky View,” she said. “It was extremely severe.
“The grower was swathing and noticed just that the field didn’t look right, really, and asked somebody to come and take a look. Samples were sent away and it was confirmed. But to be honest, the infestation was so advanced that the lab results were an important part but they were a formality.”
Barnes said the discovery has already prompted more extensive surveying in Rocky View County, as well as the surrounding rural municipalities of Foothills, Vulcan and Wheatland.
“I’m expecting we’re going to be finding more clubroot now that we’re looking for it more aggressively in that area,” she said.
The exact location of the infected field and the identity of the landowner have not been revealed, which is policy. There’s a stigma associated with having clubroot confirmed on a property and Barnes worries that might keep people from reporting it.
“If there are no clubroot cases confirmed further south, then I think that’s great but if there are, we need to know about them so that we can actually study it and give growers the tools that they need to farm profitably.”
She said farmers with infected fields are not necessarily farming irresponsibly or doing anything different from their peers. Sometimes it’s a matter of chance, given the ease with which spores can travel.
“I’m so grateful that the grower was brave enough to come forward,” Barnes said of the Rocky View case. “The more we talk about it, the more it comes in the open, I think the more comfortable people will be with managing it, because it is manageable. In this case, the grower came forward and notified the people who need to be notified.”
Alberta Agriculture crop pathologist Michael Harding echoed that view.
“We need to know where it’s at and we need to try to keep it contained. In the south, we still have the opportunity to do that,” he said.
Harvest is the ideal time to scout fields for clubroot, he added. Growers should pull 20 to 30 plants at various points and examine the roots for galls.
Barnes noted that at this time of year, galls might be starting to decompose and may not look like the hard white bulbous growths commonly seen in photos. Farmers in doubt can call canola council agronomists for an opinion or send samples to one of several labs that can test for clubroot.
“If you’re a canola grower in southern Alberta, it’s a good idea to even think about clubroot resistance in your seed when you’re booking seed right now,” Barnes added.