Introduction
Two rust diseases of corn occur in Nebraska and in
other temperate areas. Common rust of corn occurs every
year to some extent, and is caused by the fungus Puccinia
sorghi. The other rust disease, southern rust, is caused by
Puccinia polysora and occurs less frequently in Nebraska.
Both diseases can increase in severity rapidly, particularly if
infection occurs early in the growing season and favorable
environmental conditions persist for extended periods of
time. Southern rust poses a much greater threat than com-
mon rust to field dent corn production because it is a more
aggressive pathogen and most corn hybrids lack resistance.