Disease Note

Bacterial Stalk and Top Rot of Maize in Florida Caused by Erwinia chrysanthemi pv. zeae.. C. A. Lopes, Plant Pathology Department, University of Florida, Gainesville 32611. R. E. Stall, and J. A. Bartz, Plant Pathology Department, University of Florida, Gainesville 32611. Plant Dis. 70:259. Accepted for publication 28 October 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-259a.

Sprinkler-irrigated inbred lines of corn (Zea mays L.) in field plots at Gainesville, Florida, developed 1–7% incidence of stalk and top rot during 1984 and 1985. Symptoms of stalk and top rot have also been observed in corn planted elsewhere in the state. Isolations from rotted stalks consistently yielded a pectolytic, gram-negative, oxidase-negative, fermentative bacterium that produced phosphatase and lecithinase. Bacteria (20 cfu/ml) with identical characteristics were isolated from surrounding lake water used for irrigation. All cultures caused soft rot on potato tubers; four of five cultures from cornstalks and one of four cultures from lake water induced stalk rot on greenhouse-grown sweet corn cultivar Merit. This is evidence that the irrigation water might have been the primary source of inoculum for the disease. The pathogen was identified as Erwinia chrysanthemi pv. zeae (Sabet) Victoria, Arboleda & Muñoz. This is the first report on the occurrence of this pathogen in Florida.