| | Byron Puchalski has extensively surveyed southern Alberta cereal fields for stripe rust. On July 3rd, he reported: "Most of the winter wheat is either at or just completed flowering. The late April spring wheat is emerging from the boot and just beginning to flower. Losses in winter wheat will be less than last year due to the slow start. The Burdett-Grassy Lake area has been aggressively sprayed and movement of rust out of this area has been slow. We are unable to find stripe rust north of Highway #1 and Three Hills, Drumheller, Bassano, Brooks, Tilley, Medicine Hat surveyed clean.
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Areas previously identified on alert should remain on alert as the spring wheat is coming into a stage where infection is more likely.
Some fields in Fort McLeod, Granum, Claresholm and Vulcan now have stripe rust. Incidence and severity levels observed in the Granum-Claresholm region in some fields suggest it is time to consider a fungicide application. These areas should now be in the stripe rust alert zone.
It is wet everywhere in the South and conditions are ideal for disease development and spread. Don’t expect to see a lot of pustules as the winds and the rains have stripped the leaves of most pustules. Symptoms are not "text-book" in appearance. Be aware of other pests and diseases that can enhance misdiagnosis of stripe rust. For example, tan spot and physiological leaf spots are beginning to develop and have advanced to the flag leaf. As a result, chlorotic flecks are common throughout the south. Additionally, cereal leaf beetle is well established in some areas and may lead to stripes that mimic stripe rust infection.
Cereal plots at AAFC-Lethbridge were close to stripe rust free before Canada Day. This week incidence is at 1% and severity at 2%, so the disease is beginning to build up. Both winter and early sown spring wheat trials at AAFC-Lethbridge have rust.
The south region has received numerous spore shower events in the past week.
No stripe rust has been observed in barley, just trace levels of scald.
Winter wheat yield potential is excellent if they can stay rust free.
Conditions last week were not condusive to either surveying or spraying, farmers in the alert regions should empty the water out of their rubber boots and take another look.
Further North, Drs. Kequan Xi and Krishan Kumar report on July 4th that they "have observed stripe rust pustules on winter wheat in the Lacombe breeding plots on June 26. More pustules were observed in the middle canopy of winter wheat plots in Lacombe several days ago. Pustules were also found in a spring wheat differential in the plots at Olds. No stripe rust was observed in spring wheat or barley in Lacombe."
Cereal producers should be aware that ALL winter wheat varieties are susceptible to stripe rust and should be sprayed if stripes are evident on leaves. Many hard red and durum spring wheat varieties are resistant and may not need to be sprayed. Producers should refer to the provincial recommendation lists for stripe rust resistance ratings for individual varieties before considering spraying as a control option.
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex4069
Recommendations:
• For Counties Lethbridge, Taber, 40 Mile and Willow Creek - daily monitoring of fields, and fungicide application where needed, for winter and spring wheat.
• For Counties Cypress, Cardston, Warner, Newell, McLeod, Pincher Creek, and Vulcan, regular monitoring of winter wheat and spring wheat fields.
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