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Disease Note. An Outbreak of Stewart’s Bacterial Wilt of Corn in New York State. H. R. Dillard, Department of Plant Pathology, Cornell University, Geneva, NY 14456. W. L. Kline, Cornell Cooperative Extension of Genesee County, Batavia, NY 14020. Plant Dis. 73:273. Accepted for publication 23 December 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0273C. A severe outbreak of Stewart's bacterial wilt, caused by Erwinia stewartii (E. F. Smith) Dye, was observed in 1,360 ha of processing sweet corn (Zea mays L. 'Jubilee') grown in western New York in 1988. Pale green to yellow streaks with irregular margins developed on the leaves, which later senesced. Severely diseased plants died 2-4 wk before harvest. Bacteria from symptomatic leaves were isolated on Miller-Schroth medium (2) and were used to inoculate sweet corn seedlings in the greenhouse. The symptoms that developed were similar to those observed on naturally infected plants, and the pathogen (E. stewartii) was reisolated from symptomatic leaves. Disease was most severe in fields closest to Lake Ontario and was associated with extensive feeding injury by the vector, the corn flea beetle (Chaetocnema pulicaria Melsh.). Processors estimate yield losses of 5,714 t worth about $341,755 in four counties. This is the first major outbreak of Stewart's bacterial wilt in western New York since 1932 and 1933 (1). |