Bacterial stalk rot of corn
Bacterial stalk rot is caused by Erwinia dissolvens. It can occur any time during the season, particularly if conditions are very wet. It causes decay of the first internode above the soil. The rind and the pith become soft, brown, and water-soaked. Affected plants have a foul odor. The stalk typically twists and falls over, but the plant may remain green for several weeks because the vascular tissue is not destroyed. Some hybrids are more susceptible than others.
Erwinia chrysanthemi, another bacterium, can cause bacterial top rot. With bacterial top rot, the upper leaves become gray to brown with shortened internodes. The outside of the stalk may be brown to black and water soaked. The leaf tissue within the whorl and the growing point of the stem within the whorl are brown, wet, slimy, and have a foul odor that smells like silage.
Gallery Images: D. Mueller and T. Faske