Stripe rust is appearing in the Palouse region
Yesterday, we were checking fields around Pullman, Washington (Whitman County). Winter wheat and barley arranged from Feekes 5 to 7. We were able to find stripe rust on susceptible checks in all our experimental fields at the Palouse Conservation Field Station, Plant Path Farm, and Spillman Farm. The incidence was low (<0.01%) in all locations, as the rust just started producing spores (Figure 1).
The observations of stripe rust in these locations are about one month later than that of last year, but about the normal time to see stripe rust in the Palouse region. With the weather conditions in the recent weeks have been favorable and those of the next couple of weeks forecast to be favorable to stripe rust, the disease would be developed to a significant level. Based on the current stripe rust situation and prediction, our recommendations are the same as we issued in the last stripe rust update (April 18). Fungicide applications are recommended for winter wheat fields planted with susceptible and moderately susceptible varieties (stripe rust ratings 6 to 9) before flowering. For spring wheat, please consider fungicide application at the time of herbicide application for the fields planted with susceptible (stripe rust ratings 8 and 9) or moderately susceptible (stripe rust ratings 6 and 7) varieties. It is always recommended to check your fields. If you see active rust like the above picture or rust incidence (percentage of leaves with rust) reaches 5%, you should apply a fungicide labeled for stripe rust as soon as possible.
Stripe rust in the country
So far, stripe rust has been reported in Louisiana, Texas, Georgia, Washington, Oregon, California, Oklahoma, and Kansas. Compared to last year, stripe rust has been relatively low in the Great Plains and southeastern region. However, growers should check their wheat or barley fields for signs of stripe rust and apply fungicides when needed, following recommendations in their region.