Stem rust of wheat and barley (Puccinia graminis f. sp. tritici) has occurred sporadically in the Pacific Northwest USA the last 30 years. Since 2007, weather patterns have been more conducive to its appearance in eastern Washington, northern Idaho, and western Oregon.
The common barberry (Berberis vulgaris) is the alternate host to the stem rust fungus, and is crucial to the pathogen completing its life cycle.
This website is an educational tool produced by the scientists working on this problem.
Stem Rust Update August 13 2012 - Xianming Chen