WSU Stripe Rust Forecast Show Little Change

According to Washington State University, there has been little change in the most recent stripe rust forecast.  The April 10^th figures show active stripe rust was observed in breeding nurseries at Central Ferry in Garfield County, and rust monitoring plots in Walla Walla and the OSU Research Center in Hermiston.  The only stripe rust found in commercial fields was in the Horse Heaven Hills in Benton County, where incidence was 5%, and near Connell in Franklin County, where incidence was limited to one plant.  No stripe rust was found in commercial fields in Adams, Columbia, Franklin, Garfield, Walla Walla, and Whitman counties in WA, and Umatilla County, OR.

Because of that the forecast for potential damage from stripe rust of 18% on susceptible checks holds.  For susceptible varieties rated 5 to 9 in the Seed Buyer’s Guide, fungicide application at herbicide timing is recommended, but already past in many areas. For more resistant varieties rated less than 5, and fields with susceptible varieties to which a fungicide may or may not have been applied, make sure to scout the field for stripe rust and apply a fungicide if 5% rust incidence or severity is found. Fungicide application should not be needed for resistant varieties rated 1 to 3.

Although this update brings good news, the temperatures over the past month have been on the cool side, which likely limited rust development. With temperatures predicted to rise over the coming week, it’s important to continue scouting fields for rust because this disease can increase rapidly under favorable conditions. It’s also important to remember that the fungicides used for stripe rust control have different growth stage restrictions and preharvest intervals for application. Make sure to read the label prior to application.

If you haven’t planted spring wheat yet, remember we always recommend planting the most resistant variety possible (rated 1 to 3) that performs well in your production area. You can use the Variety Selection tool to learn more about the resistant ratings of varieties.

If you have a story idea for the Washington Ag Network, call (509) 547-1618, or e-mail gvaagen@cherrycreekradio.com