New strain of clubroot can infect resistant canola
A plant pathologist with Alberta Agriculture and Rural Development says the canola industry is better prepared to deal with a new strain of clubroot than it was when the disease first arrived in Alberta a decade ago.
Michael Harding, who works at the province’s Crop Diversification Centre at Brooks, said the discovery near Edmonton of a clubroot pathotype that can infect resistant varieties of canola is a serious matter. But 11 years of research and learning to manage the pathogen should help reduce the threat.
“I think with the heightened awareness, better understanding of how to manage it and how to do sanitization and biosecurity measures, we’re ahead of the game with respect to this pathogen compared to where we were back in 2003.”
Earlier this year, University of Alberta researcher Stephen Strelkov discovered higher-than-expected infestations of clubroot in fields of resistant canola.
Subsequent research indicated that none of seven clubroot-resistant canolas were effective against this particular strain.
“This is a different pathotype that none of the commercially available clubroot resistant varieties in Western Canada are effective at managing,” said Strelkov in a recent release by the Canola Council of Canada. “That’s a huge concern and we don’t want it to spread to new sites,” said Harding, describing current efforts to determine the severity and extent of the spread.
Farmers are being urged to reduce the frequency with which they grow canola, since a shorter crop rotation increases the likelihood of clubroot adapting to plant resistance.
Other recommended practices include scouting for clubroot — even where disease-resistant canola has been seeded, sanitization of equipment moving between fields and avoiding unnecessary field operations in clubroot regions, said Harding.
Because clubroot has the ability to shuffle its genetic information over time, this new pathotype wasn’t unexpected, he said.
“This has happened before in other parts of the world, on crops other than canola and on canola.”
Strelkov said tests have indicated that resistance genes to this new strain do exist. But it will take time to incorporate these into a new commercial variety of canola.
Harding pointed out that it took four to five years to develop resistant canola after clubroot was first discovered in Alberta.
“I don’t think it will happen quicker than that,” he said of this next generation of resistant plants, pointing out that they must be suitable for this climate and high-yielding.
Meanwhile, said Harding, there are other pests that threaten canola crops — especially when producers forego preventive measures like proper rotation periods.
These include blackleg and swede midge, with the latter insect recently found in Saskatchewan crops.