Canola School: Blackleg levels up, sclerotinia down, and a changing clubroot threat
Every once in a while a group with a real passion for something get a chance to get together and talk about what they care about. If you get to be in room with with them, you can’t help but feel the energy and, most likely, learn something. The Western Forum on Pest Management (WFPM) that was held recently at Lloydminster, Alta., is just that kind of meeting.
The WFPM brings together researchers, agronomists, farmers, and students to discuss the pests that threaten food production in Western Canada. RealAgriculture’s Dale Leftwich attended the meeting and managed to catch up with Barb Ziesman, plant disease specialist with the Province of Saskatchewan. In this edition of the Canola School they talk about the results of the oilseed disease roundup that Ziesman presented to the group.
Ziesman says disease levels were generally down due to the dry growing conditions, but with regional differences. Blackleg, however, proved to be the exception. “The interesting thing is that we did see variation in the different provinces as well. But generally speaking, (there were) lower disease levels, blackleg was a bit higher. We had about 70 per cent prevalence across all three provinces. When we talk about prevalence we mean the number of fields that we looked at had the disease present.”
Disease ratings are based on prevalence, incidence, and severity, Ziesmans explains. Prevalence reflects the percentage of fields that are affected. The incidence is determined when surveys are done and plants with disease are counted. Severity is a measurement of disease impact on the crop.
The clubroot story continues to evolve. In Alberta, two new strains of the disease that have overcome an available resistance gene have been identified. In Saskatchewan, the 1,800-field survey that was planned in the spring was successfully completed. The results are now being compiled, and should be available late 2018 or early 2019.
Sclerotinia levels were lower across the Prairies, Ziesman adds.