Southern rust develops more rapidly and is more destructive to leaf tissue than common rust, Southern rust develops more rapidly and is more destructive to leaf tissue. The many pustules that form cause the leaf to turn yellow and die. Spores blown into the Midwest from the South. The widespread use of corn hybrids containing the Texas male-sterile cytoplasm. Consequently, southern rust occurs later in the growing season, and is more prevalent in the southern states.
Chemical control is available to growers through mancozeb fungicides.
If plants become infected early in their development, sweet corn quality and yield will be affected significantly. Typical symptoms of the disease which impact yield and quality are poor tip fill and shallow kernel depth. In severe cases, barren ears result. Thus, the uredospores needed to initiate rust epidemics are believed to be windblown into the continental U.S. from tropical and subtropical areas. These conditions frequently occur during the early part of the growing season in the Midsouth.