Puccinia graminis f. sp. tritici (Pgt) has significantly impacted worldwide wheat (Triticum aestivum L.) production throughout human history. The most recent wheat stem rust outbreak in the United States was reported around 1953 - 1954, with an estimated 40% yield loss. The loss in yield is attributable to several factors associated with the colonization of Pgt on its poaceous hosts. These include competition with the fungus for nutrients, lodging due to weakened stems, and reduced metabolic efficiency. Telial host range includes wheat, (Triticum aestivum), barley (Hordeum vulgare), goatgrass (Aegilops spp.), and wild rye (Elymus spp.). Aecial host range includes common barberry (Berberis vulgaris), additional Berberis spp., Mahoberberis spp., and Mahonia spp.