Here is a mini update regarding wind trajectories and regional rust development in relation to Prairie cereal rust risk.
The full report can be found at: July 14-20, 2020 cereal rust risk update
Given the state of maturity and harvest in the USA on winter wheat, these regions no longer represent a significant source of rust inoculum for the Prairie region and the weekly full PCDMN updates for 2020 have finished for these areas. However, spring cereals in these regions may still represent a source of rust inoculum although the acreage of spring wheat is typically lower than that of winter wheat, depending on the State.
With the appearance of stripe rust in ten southern Alberta municipalities, at Beaverlodge in the Country of Grande Prairie, in the Fort St. John/Dawson Creek region of BC, and at four locations in Saskatchewan, farmers in these regions should be on the look out for stripe rust in wheat. In addition, farmers in regions north and east to northeast of southern Alberta should be on alert as southerly winds may transport stripe rust spores. Moreover, trajectory analysis from July 14-20, 2020 has indicated a total of 13 of 29 locations where wind trajectories previously passed over the stripe rust area of southern AB. Special focus should be on wheat fields seeded to varieties rated as susceptible or moderately susceptible. Also, given the appearance of crown rust in the Mannville region of Alberta, as well as at Carman, Manitoba, oat growers in this area need to be on the look out for crown rust.
Growers with very late seeded fields of wheat or perhaps barley for swath grazing may want to be especially diligent in terms of scouting for stripe rust. Over the years some of the most severe stripe rust epidemics have occurred in wheat fields seeded late (e.g. June) for swath grazing, especially where the variety was susceptible.
