While no cases have been reported in Wyoming, stripe rust is being seen earlier than normal in Colorado, Kansas, Idaho, Montana, Nebraska and Utah, said 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 cool, wet conditions required for disease development, Stump said.
Stripe rust was an issue last year in southeast Wyoming and was found in fall-planted wheat but none 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,” said Stump.
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, said Stump.
Of the three most planted varieties in Wyoming, Cowboy is susceptible, Buckskin is moderately susceptible and Pronghorn is resistant, he said. Whether spraying for wheat stripe in dryland wheat can yield a return is unknown, but Stump said spraying irrigated wheat can be profitable.
Source: University of Wyoming Extension