During the growing season, reports on the current rust situation and how it is progressing in the United States are available in the Cereal Rust Bulletins from the USDA at: http://www.ars.usda.gov/Main/docs.htm?docid=9757. Recently, crown rust has been reported in South Dakota and Minnesota. These reports provide growers in Manitoba the opportunity to proactively scout for crown rust in their oat fields.
As a reminder, there have been changes within the crown rust pathogen populations in Manitoba where virulence has developed on a number of oat varieties. Varieties that contain the Pc91 gene, including AAC Justice, CDC Morrison, HiFi, Souris and Stainless, had been redefined for crown rust resistance in Seed Manitoba 2016 (www.seedmb.ca). The variety Summit, which is postulated to carry different resistance genes, is also losing its resistance to virulent races in the Eastern Prairies; therefore, it had also been redefined for crown rust resistance.
There are a number of steps used to determined if changes are occurring within the crown rust pathogen populations, and then whether changes in variety disease resistance ratings are required. Please take the time to read the attached article to learn more about how and why the crown rust resistance ratings did change in Seed Manitoba 2016.
Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture
With information from Dr. Jim Menzies, Phytopathologist, AAFC Morden & Dr. Jennifer Mitchell-Fetch, Oat Breeder, AAFC Brandon