WSU: Stripe Rust Numbers On The Way Up

According to Washington State University, stripe rust will potentially cause yield loss of 17.9% on highly susceptible varieties.  That figure is based on forecast models using the weather data from November 2017 to February 2018.  This number is much higher than the 6% forecasted in January.  The number is an average of the prediction range from 13.8% to 23.4% using six models.

Strip rust has already been found around the Walla Walla area.  According to WSU,  the most “susceptible” commercially grown varieties, such as Xerpha, ORCL 102, and Eltan, will likely to have 8-12% yield losses, which still warrant fungicide application.

What should Northwest growers do?  WSU recommends:

For winter wheat, if a susceptible or moderately susceptible variety (ratings 5 to 9 on the Buyers’ Guide) is planted, or you can found stripe rust in the field, consider using fungicide at the time of herbicide application. These varieties include ORCF-103 (rating 8), Xerpha (rating 7), ORCF 102 (rating 6), AP503 CL2 (rating 5), ARS-Crescent (rating 5), Eltan (rating 5), KWS 145 (rating 5), Mary (rating 5), and SY 107 (rating 5) based on the tests in the last year. Different from the last year, one time application may be adequate for fields grown with such “susceptible” varieties depending upon the area. The key is to check fields and only apply fungicide when rust can be found. For varieties with stripe rust rating 4, check the field and apply fungicide only when rust can be found. For varieties rated 1 to 3, fungicide application is not recommended.

For spring wheat, always consider planting resistant varieties. Use the Seed Buyers Guide to choose varieties rated 1 to 4 for stripe rust and avoid those rated 5-9 if possible.

With spring wheat planting season approaching, WSU recommends planting the most resistant variety possible that performs well in your production area. You can use the Variety Selection tool to learn more.

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