By Top Crop Manager
July 16, 2014, Alberta – Central Alberta continues to report severe stripe rust in winter and spring cereals, according to Alberta Agriculture and Rural Development (AARD). It is very important to scout wheat and barley fields for stripe rust in all areas of the province as stripe rust is now reported from southern, central and northern regions, including the Peace region.
In southern Alberta, Dr. Denis Gaudet and his survey crew reported that 24 winter wheat and 10 spring wheat fields were surveyed for stripe rust in the Lethbridge, Cardston, Warner counties southern Alberta during the week of July 7 to 11. In general, stripe rust is well established in winter wheat in the above counties and is moving to the spring wheat. Further east through Forty Mile and Cypress counties, stripe rust is developing less rapidly but the situation could change rapidly depending on weather conditions. While the majority of the winter wheat fields had trace to light levels, approximately 40 per cent of the fields had moderate to severe levels.
Producers are encouraged to go out and routinely monitor their wheat fields for the presence of the long, bright orange stripes on the upper leaves. Spraying is recommended in winter wheat if stripe rust exceeds exceed an average of one infected plant/square metre in fields and the crop stage is still within the window for spraying.
For individuals considering spraying fields spring wheat with a fungicide, AARD recommends the following:
- Only consider spraying if the spring wheat variety is considered susceptible. Durum varieties are highly resistant and do not require spraying; AC Carberry, AC Lillian, AC Muchmore, Pasteur, CDC Go, Sadash and AC Andrew are considered moderate resistant to resistant and should not require spraying. Glenn is intermediate and should be monitored for disease progression.
- Producers should check with the Varieties of Cereal and Oilseed Crops for Alberta to verify the stripe rust resistance rating for their seeded spring wheat variety. Those varieties with ratings of Intermediate to Susceptible should be monitored for stripe rust infection before spraying.
- Spray wheat when infection levels approach or exceed an average of one infected plant/square metre.
- Within the context of this year’s epidemic, if the producers choose to spray, it is important to protect the last two leaves that emerge (the flag and flag minus 1 leaves) because they contribute most to plant yield and quality.
Weekly surveys for stripe rust will continue until the end of the growing season.