Identification of Erwinia sp., causing stalk rot of maize in Egypt.

The physiological characteristics, pathogenic propensities, and the sensitivity towards certain antibiotics of the causal bacterium of stalk rot of maize, isolated in Egypt, were studied. Different isolates of Erwinia carotovora and E. atroseptica were included for comparative studies. The antibiotic sensitivity tests (including erythromycin) are of no value in differentiating between E. carotovora and E. atroseptica. The cultures of the causal bacterium of stalk rot of maize showed physiological characteristics similar to those known for E. chrysanthemi. The pathogenic propensities of E. chrysanthemi isolates suggest the presence of a number of pathotypes of E. chrysanthemi. The proposal of HARTMAN and KELMAN to identify maize stalk rot pathogen as E. chrysanthemi (corn pathotype) seems, therefore, to be the most appropriate name for this bacterium.