Common Rust (fungus - Puccinia sorghi): Common rust occurs in most home gardens and commercial fields, but seldom causes economic losses. Infected leaves have raised spots or pustules formed primarily on the upper surface. The pustules are rectangular to oval, brick red, and may occur in bands on the leaf. Spores are produced in the pustules, which are blown to neighboring leaves where infection can be repeated. Infection is encouraged by high humidity and cool temperatures (60 to 70o F).
