Disease Note Maize Dwarf Mosaic Virus in Sweet Corn in Washington State. D. A. Johnson, Irrigated Agriculture Research and Extension Center, Prosser, WA 99350. G. I. Mink, and W. E. Howell, Irrigated Agriculture Research and Extension Center, Prosser, WA 99350. Plant Disease 68:351, 1984. Accepted for publication 3 January 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-351c. Maize dwarf mosaic virus (MDMV) had been reported in the Pacific Northwest only from southern Idaho. In July 1983, we observed mosaic symptoms at the base of young leaves on Zea mays L. var. saccharatain several late-planted Washington fields. Moderate stunting and chlorosis of diseased plants followed. Flexuous rods about 750 nm long, typical of the potyvirus group, were observed by electron microscopy in dip preparations from field-infected and greenhouse-inoculated plants. These particles decorated with an antiserum against MDMV strain B but not strain A (both obtained from D. T. Gordon). Incidence of MDMV on 5 August ranged from 0.2 to-l% in 12 fields in Benton and Yakima counties, WA. No virus symptoms were observed in over 21,000 plants grown in a greenhouse from seed lots used to plant the 12 fields. |