June 17, 2014 - Research has confirmed the presence of a different clubroot pathotype in the Edmonton region that can overcome current forms of clubroot resistance.
Earlier this year, Dr. Stephen Strelkov at the University of Alberta investigated samples collected from several fields and verified higher levels of infection than expected in some clubroot resistant varieties. He recently completed his second phase of testing on these pathogen populations.
"This is a different pathotype that none of the commercially available clubroot resistant varieties in Western Canada are effective at managing," says Strelkov. "Testing has shown that there are resistance genes available."
Attention needs to be paid to help prevent the pathogen's buildup and movement, and equipment sanitation is the first line of defense. "We are advising that growers practice good sanitation on their equipment, especially during spraying under wet conditions," says Curtis Rempel, vice president of crop production and innovation with the Canola Council of Canada (CCC). "This applies to equipment moving between all fields, not just those currently growing canola, since clubroot spores remain in the soil for years."
The level of sanitation should be based on the level of clubroot risk, and can include knocking or scraping off soil lumps and sweeping off loose soil, fine cleaning with a pressure washer and disinfection. Growers can use the following questions and consult the Equipment Sanitation Guide available on www.clubroot.ca to help decide how much sanitation is needed:
- Do you already have clubroot in at least one field?
- Have you purchased equipment that may have originated in clubroot infested areas?
- Has your equipment been used in fields in infested areas?
- Who has access to your land?
- Do you use tillage?
The CCC also advises that canola growers and agronomists scout their clubroot resistant varieties this summer with extra effort and vigilance. A focused survey in the Edmonton region is also being planned to help understand the pathogen's prevalence and distribution.
Clubroot is a serious soil-borne disease caused by the pathogen Plasmodiophora brassicae. The disease has been advancing through Alberta at a fairly steady 20 to 25 km per year, and has been detected at low levels in Manitoba and Saskatchewan. Visit www.clubroot.ca to learn more about clubroot best management practices including sanitation, long rotations, weed management and minimizing tillage.
June 19, 2014 By Canola Council of Canada