Stem Rust (fungus - Puccinia graminis f. sp. tritici): Stem rust is recognized by the elongated, ragged pustules it produces on stem, leaf, sheath, blade, chaff, beard and occasionally on young kernels. Fragments of epidermis adhere to the sides and ends of the pustules, giving a ragged appearance. The brick-red color and large elongated pustules distinguish it from leaf rust which has small round pustules and orange-red spores. Stem rust is far more devastating than leaf fust on susceptible varieties. Soft wheat varieties are generally more susceptible than hard red winter wheat varieties. Barley, rye, wild barley, and goatgrass are also susceptible. Plant resistant varieties.