Wyoming, USA
April 30, 2015
Producers are being encouraged to scout fields this spring for early signs of wheat stripe rust.
While no cases have been reported in Wyoming, stripe rust is being seen earlier than normal in Colorado, Kansas, Idaho, Montana, Nebraska and Utah, says William Stump, plant pathologist with University of Wyoming Extension.
Symptoms include long stripes of small, yellow-to-orange, blister-like pustules -- primarily on leaves -- and whose spores can be easily wiped off. Cool (45 to 60 degrees) and damp conditions favor the disease.
Reports close to Wyoming occurring earlier this year means there is increased potential for inoculum being present during the cool, wet conditions required for disease development, Stump says.
Stripe rust was an issue last year in southeast Wyoming and was found in fall-planted wheat, but no stripe rust has been found this spring.
“Typically, by the time inoculum blows up from wheat production areas south of us, warm temperatures set back disease development,” Stump says.
The disease is best managed by planting disease-resistant varieties, but can be managed with foliar fungicides applied by the boot stage to protect the flag leaf, Stump says.
Of the three most planted wheat varieties in Wyoming, Cowboy is susceptible, Buckskin is moderately susceptible and Pronghorn is resistant, he says. Whether spraying for wheat stripe in dryland wheat can yield a return is unknown, but Stump says spraying irrigated wheat can be profitable.
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