As of early May, stripe rust was observed in experimental winter wheat and barley fields around Pullman, Washington (Whitman County), with wheat growth stages ranging from Feekes 5 to 7. The disease incidence was low (<0.01%) across experimental fields at the Palouse Conservation Field Station, Plant Pathology Farm, and Spillman Farm, indicating that we are in the early stages of spore production. This observation is about a month later than last year but is typical for the Palouse region. Given recent and forecasted favorable weather for stripe rust, a significant increase in the disease is expected.
The recommendations remain the same as the April 18 update: apply fungicides to susceptible (rating 8-9) and moderately susceptible (rating 6-7) winter wheat varieties before flowering. For spring wheat with susceptible (8-9) or moderately susceptible (6-7) ratings, consider fungicide application during herbicide application. Stripe rust ratings can be found on the Variety Selection Tool located on the WSU Wheat and Small Grains website or by visiting the Seed Description & Resources page of the Washington State Crop Improvement Association’s website.
Regular field checks are crucial, and fungicide application is advised immediately if active rust is see or incidence reaches 5%. Nationally, stripe rust has been reported in several states, including Washington (experimental fields only), Oregon, and California. While the disease has been relatively low in the Great Plains and southeastern regions compared to last year, growers should monitor their fields and apply fungicides based on local recommendations when necessary.
See USDA’s Dr. Xianming Chen’s May 2025 stripe rust update.
Co-author: Tim Paulitz, USDA-ARS Pullman, timothy.paulitz@ars.usda.gov, 509-335-7077