Stripe rust was recently spotted in an irrigated wheat field near Hermiston, according to scientists with Oregon State University.
It is the first report of the fungal disease in Eastern Oregon in 2016. Stripe rust grows on the leaves of wheat plants and can reduce yield in severe cases.
Larry Lutcher, soil scientist with OSU Extension Service in Morrow County, said the disease is thus far limited to just one field. It has not yet been found in any dryland wheat.
Stripe rust tends to thrive in cool, moist conditions when farmers would otherwise expect a promising harvest, Lutcher said. The last year with substantial rust damage came in 2012.
“There’s more rain, more humidity, more leaf tissue and more opportunity for the fungus to grow,” Lutcher said.
The early start to rust season suggests farmers should take extra care scouting their fields, Lutcher said. Fungicides can help if the infection is found and treated early.
Dryland fields emerge much later than irrigated wheat. However, growers should be aware of the potential for rust later in the season.
Untreated stripe rust, which is also known as yellow rust, can reduce wheat yields by 40 percent or more, according to the U.S. Department of agriculture. The disease is caused by spores and the spores can be spread by wind.
Fields infected by stripe rust are commonly treated with a fungicide spray.