Cold winter, wet spring lead to wheat disease in eastern Oregon

May 22, 2017
stripe rust on wheat
The crop-damaging fungus known as stripe rust on a wheat plant. Photo courtesy Christina Hagerty, Oregon State University.

CORVALLIS, Ore. – The record-setting wet spring in the Pacific Northwest – preceded by a snowy winter – has brought a variety of plant diseases to Oregon’s wheat crop.

Wheat disease is significant in Oregon, where the grain ranks among the state’s top-valued agricultural commodities. The state is known for its soft white winter wheat, most of which is exported to Asia for its use in noodles.

Stripe rust arrived in the fall and spread quickly on susceptible winter and spring wheat varieties in Oregon State University test plots. Cool and wet conditions in eastern Oregon continue to favor the fungal disease, said Christina Hagerty, a wheat pathologist in OSU’s College of Agricultural Sciences.

“This pathogen needs high humidity and high moisture,” said Hagerty, who conducts research at OSU’s Columbia Basin Agricultural Research Center just outside Pendleton. “This season is shaping up to have higher-than-average stripe rust infection and spread, and the wet and snowy conditions brought some rarer diseases to the forefront, such as soilborne wheat mosaic virus and snow mold.”

Many growers in eastern Oregon and southern Washington and western Idaho are considering an extra fungicide application, she said, describing it as a “challenging decision” because of the expense. Stripe rust and other diseases are mainly affecting winter wheat, to be harvested in late summer along with spring wheat.

There isn’t much the growers can do about snow mold, however, on Oregon’s grain belt.

“Growers in this region tell me they haven’t see snow mold for 30 years,” she said. “We may not have a snow mold problem for another decade or more.”

OSU works with wheat growers to control plant disease in three basic ways – cultural control, which includes seeding date, tillage and crop rotation; host resistance, which includes planting genetically resistant/tolerant varieties; and pesticides.

“A really good pathogen management plan typically includes all three techniques in some capacity,” Hagerty said.

For more information, go to OSU Extension’s publication Controlling Wheat and Crown Diseases of Small Grain Cereals.

Author: Chris Branam