Stripe Rust Continues To Spread Across The PNW

Stripe rust continues to spread across the Pacific Northwest.  Washington State University plant pathologists says the recent cool temperatures and periodic showers have slowed the spread of the fungal disease.

WSU noted stripe rust severity has reached as high as 100% on susceptible winter wheat varieties in research nurseries across Washington and Oregon.  While no major changes have been detected in stripe rust races or variety reactions, experts say widespread infections last fall, a mild winter, and early spring development have increased disease pressure this season.

Photo: WSU

A Mild Winter Has Increased Disease Pressures

Xianming Chen, Research Plant Pathologist, said in commercial fields by the last week, the winter wheat crop ranged from heading to milk depending upon areas and planting dates.  Stripe rust was generally under control with some fields showing stripe rust infections.  Spring wheat ranged from early jointing to boot, and stripe rust was found at low levels in some fields from Adams County to Whitman County in the last week. 

Growers are encouraged to scout fields regularly.  Chen said the weather conditions in the last two weeks and forecast for the next two weeks have been and will be continually favorable to stripe rust infection and development.  For winter wheat, he said, stripe rust control is over for fields of crops after the flowering stage.  However, for fields of crops not reaching the flowering stage (Feekes 10.5) but with active stripe rust, fungicide application may still be needed.

Photo: WSU

Stripe Rust Reported In Barley Too

Stripe rust has been reported in all three Northwest states, as well as Kansas, Texas and eight others.

Barley stripe rust has occurred in winter barley nurseries in all our experimental fields with severity reaching 80 to 100% at Central Ferry and Mount Vernon.  WSU noted the recommendations for spring wheat are also applicable to spring barley. 

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