Stripe rust update 0322: Stripe rust likely low this year in eastern PNW

by Dr. Xianming Chen

This unusual winter appears over, and spring comes late but suddenly. Based on the forecast models, we predict that stripe rust will potentially cause yield loss of 16 percent on highly susceptible varieties. This level is much lower than the 38 percent forecasted in January due to the cold February. Based the current forecast, stripe rust will likely be in the low epidemic range (0-20 percent yield loss). According to this prediction, the most “susceptible” commercially grown varieties, such as Xerpha, Eltan, SY 107 and Keldin, will likely to have up to 8 percent yield losses, which may need fungicide application, while the majority of varieties that are rated 1 to 4 may not need fungicides. 

No stripe rust was found in the field survey last week 

Last week, we were checking wheat fields in Garfield, Columbia, Walla Walla, Benton, Franklin, Grant, Lincoln and Adams counties. Thanks to the warm weather, most fields came out from under snow. Wheat plants ranged from Feekes 1 to 5, but has not regrown yet. The snow cover from the second week of February protected wheat plants from winter kill. Winter injury was spotty and mostly on leaf tips. Snow mold and wireworm damage were found in Horse Heaven Hills of Benton County and in Grant County. No stripe rust was found in any of the checked fields, probably due to the relatively low infection last fall. Stripe rust fungus that got into leaf tissues last fall should have survived the coldest February but under protection of snow cover. 

So far, stripe rust of wheat has been reported in Texas and Louisiana and stripe rust of barley in Corvallis, Ore., this year.