is a disease that frequents corn fields ne … is a disease that frequents corn fields nearly every year. However, infections and associated corn grain yield loss are usually very minimal. Infection normally occurs from late-May to early-July.
Common rust has cinnamon-brown colored round to elongated pustules that frequently form in bands on the lower part of the leaf, which result from infection when the leaf was in the whorl. Common rust pustules form on both upper and lower sides of an individual leaf, distinguishing Common from Southern rust, which predominately sporulates on the upper leaf surface.
Common rust development requires relatively cool to moderate temperatures (54 to 82 degrees F) and nearly 100% relative humidity for about six hours. Rust development is much more likely in pre-tassel stage corn, because a large whorl provides a humid, protected environment, and young leaf tissue is more susceptible to infection than emerged leaves. After tasseling, all leaves are completely emerged (past whorl stage) and should be relatively immune to further common rust development. immune to further common rust development.