Black stem rust (Ug99) Puccinia graminis f.sp. tritici (Ug99) is a serious disease of wheat and barley. While wheat in the United States is resistant to most strains of black stem rust, it is not ...

The yellow structure was a floral mimic constructed by the plant, but designed by the rust. Puccinia monoica is a rust that uses several species of grasses as its primary host and several species of ...