Stripe Rust Forecast and Update, March 4 2026

A. Stripe rust is forecasted in the upper range of severe epidemics for the eastern Pacific Northwest

B. Stripe rust is widespread, and the pathogen is actively producing spores in central Washington

C. Recommendation for Managing Stripe Rust in the Pacific Northwest

The field observations show the unusually early development of stripe rust, and the predictions indicate high potential yield losses in the 2026 wheat crop season for the eastern Pacific Northwest. Fungicide application is recommended for the winter wheat fields planted with moderately resistant to susceptible varieties with stripe rust ratings 3 to 9 at the time of herbicide application, and a second application may be needed 20 to 30 days after the first application, which can be determined by whether active stripe rust appears in the field after the first application. As many resistant varieties (stripe rust ratings 1 and 2) have only high-temperature adult-plant (HTAP) resistance, which will not be effective until the weather gets warm and plants reach the middle jointing stage (Feekes 7), stripe rust can develop on these varieties. Therefore, any wheat fields should be checked for stripe rust. If active rust like those shown in the figures above, fungicide should be applied at the timing of herbicide application. Refer to my previous report “2026 First Stripe Rust Forecast for the Eastern Pacific Northwest” for stripe rust ratings of wheat varieties (2026 First Stripe Rust Forecast).
For spring wheat, resistant varieties (stripe rust ratings 1 or 2) should be selected for planting.  If for any reason varieties in the other categories (stripe rust ratings 3 to 9) are going to be planted, fungicide application will be likely needed at the time of herbicide application.

To select fungicides, please refer to the Appendix Table for information on active ingredients, application rate, control effect, effective duration, total limit per crop, and stage or date of application restriction.

D. Stripe Rust in the Country

In 2026, stripe rust was first reported in central Washington on January 15, Pendleton, Oregon (Umatilla County), on January 27, Davis, California (Yolo County) on February 9, and the Hill and McLennan counties, Texas on January 12. The observations of stripe rust in the Davis area of California were also unusually earlier than normal. The occurrence of stripe rust in Texas in January is an indication of severe epidemic in the southern Great Plains and potentially epidemics in the central and northern parts of the Great Plains.