Virus infecting Southern Idaho wheat, barley crops, forcing tough choices for growers

University of Idaho plant disease specialist Juliet Marshall is warning farmers that winter wheat and barley crops across southern Idaho are showing a disturbing echo of last summer's abnormal wet spell.

Barley yellow dwarf virus, a major disease threat to wheat and barley, is rampant from Parma to Ririe, said Marshall, a UI Extension cereal pathologist.

An early spring that put wheat and barley crops three to four weeks ahead of average across southern Idaho helped highlight the problem.

The first symptoms of the viral disease began showing up in fields in early March, Marshall warned farmers in an advisory issued Friday. Twice in the past two weeks she has traveled across southern Idaho to gather more information.

In most areas, 85 to 95 percent of winter wheat fields are showing nearly total viral infection. Lab tests conducted in collaboration with UI Extension entomologist Arash Rashed confirmed the virus in samples from throughout the southern portion of the state. Some growers, Marshall said, are killing infected fields, plowing and reseeding with spring grains or dry beans.

The virus can greatly reduce yields, test weight and plumps. As a result, infected winter wheat may be suitable only for use as livestock grains after harvest. Infected winter barley probably will not be high enough quality for use in malting.

The wheat growers face the worst scenario because winter wheat is that grain's biggest segment. Barley growers, however, typically rely on spring-planted grains for the bulk of their malt-quality production, their highest value crop.

Still, Marshall said, facing a dry year and advanced growing season leaves growers facing very tough agronomic and financial decisions.