Pathogen
Erwinia chrysanthemi pv. zeae (Sabet) Victoria et al. is a motile, gram-negative, rod shaped bacterium. It is commonly found throughout the corn belt of the USA and periodically causes outbreaks. In 2001, an outbreak occurred in Gosper, Phelps, and Kearney Counties of Nebraska. At least thirteen pivot/sprinkler irrigated fields had incidences of bacterial stalk and top rot in the range of 2 to 25%. Bacterial top rot can be caused by different species of bacteria. Erwinia chrysanthemi pv. zeae is most often associated with this disease although Erwinia carotovora subsp. carotovora (Jones) Bergey et al., Enterobacter dissolvens (Rosen) Brenner et al., and Pseudomonas aveae subsp. avenaeManns have also been reported as causal agents. These bacteria survive in corn and sorghum stalks and residue. The bacteria enter the plants through natural openings; wounds from hail, high winds, or insect feeding (e.g., stalk borers) can provide additional entry sites into the plant.