Higher-than-expected levels of clubroot infection, recently confirmed in some Edmonton-area canola fields seeded to clubroot-resistant seed varieties, may suggest a new pathotype of the disease in play.
Stephen Strelkov, a professor and plant pathologist at the University of Alberta, said in a recent release that data from samples in the Edmonton region indicate some forms of clubroot resistance “are no longer functioning well” against what could be a “new clubroot pathotype.”
Clubroot, a soil-borne disease, has been moving outward from its points of arrival in Alberta at a “fairly steady” rate of 20 to 25 km per year, and has since also been seen at low levels in the other Prairie provinces.
“Current research indicates that the concern is limited to very few fields and patches within those fields” in the Edmonton region, Curtis Rempel, vice-president of crop production with the Canola Council of Canada in Winnipeg, said in a release Tuesday.
Clubroot resistance, he said, “is expected to be functional in the vast majority of acres this year, but attention needs to be paid to prevent this situation from expanding.”
The council, which since 2010 has advised growers to scout even clubroot-resistant canola fields, said it’s advising canola growers and agronomists to scout clubroot-resistant varieties this summer with “extra effort and vigilance.”
“This is very important in light of the potential for a new pathotype capable of overcoming the excellent resistance currently available in Western Canada,” said Rempel.
Clubroot is established in Canada mainly in vegetable-producing regions of British Columbia, Quebec, Ontario and Atlantic Canada and turned up in canola in Quebec in 1997.
Even after decades of large-scale canola production in Western Canada, however, it took until 2003 for clubroot to appear in Prairie canola, in spots near Edmonton in 2003. The pathogen was confirmed in fields in Saskatchewan and Manitoba in 2011 and 2013 respectively.
Factors that may diminish the effectiveness of clubroot-resistant canola, the council said, include canola rotations with less than a two-year break; lack of regular scouting in fields; seeding the same resistant canola variety in a rotation; “any tillage that is more than zero-till;” and/or excessive soil movement between fields. — AGCanada.com Network