The most recent and likely last Stripe Rust Update
of the season from Dr. Xianming Chen, USDA-ARS Pullman, came out last Friday, June 17. Although stripe rust development was slowed some by the warm temperatures in late May and early June, recent cool conditions have allowed for continued stripe rust development. Winter wheat crops across the region are in various stages of kernel development and have progressed past the point where fungicide application is beneficial. However, spring wheat and barley crops are still vulnerable and should be monitored for active stripe rust.
In general, rust on barley is less severe than on wheat, but our recommendations remain the same; scout fields and look for actively sporulating rust, regardless of the resistance reaction of the variety planted. If you find actively sporulating lesions on 5% or more of the leaves, the plants are not yet to Feeke’s 10.5.4 (anthesis complete-kernels watery ripe), and it’s been 3 weeks or more since the last fungicide application, consider another application, especially for moderately susceptible or susceptible varieties.
Make sure to read and follow label directions for all fungicides for total amount of material that can be applied to a field per season and any growth stage restrictions for application.
Stripe rust ratings on most commercially grown varieties can be found using the Variety Selection Tool. More information on stripe rust, including NCERA Fungicide 2015, is available in the foliar disease section of this website.