Effect of Inoculation with Maize Dwarf Mosaic Virus at Several Growth Stages on Yield of Sweet Corn. L. V. Gregory, Research Assistant, Department of Plant Pathology, The Pennsylvania State University, University Park 16802. J. E. Ayers, Professor, Department of Plant Pathology, The Pennsylvania State University, University Park 16802. Plant Dis. 66:801-804. Accepted for publication 8 February 1982. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-801.

Sweet corn cultivars Bonanza and Stylepak were planted at Landisville and Rock Springs, PA, in 1979 and 1980 and inoculated with maize dwarf mosaic virus strain A at different growth stages beginning at the three- to four-leaf stage and continuing at weekly intervals until the eight- to nine-leaf stage. There was no effect of virus infection on total number of ears or total fresh weight of either cultivar at Landisville in 1979. Both cultivars had significantly lower numbers of marketable ears and marketable fresh weight; greatest reductions occurred when inoculations were made at the eight- to nine-leaf stage. At Rock Springs, greatest reductions in marketable ears and fresh weight occurred when inoculations were made at the four- and eight- to nine-leaf stages for Bonanza and the six- to seven-leaf stage for Stylepak. In 1980, moisture was limiting through much of the season. Numbers of marketable ears were reduced when inoculations were made at the four- to five-leaf stage and beyond for Bonanza and at the six- to seven-leaf stage for Stylepak. At Rock Springs, there were significant reductions in marketable ears and fresh weight and total fresh weight for Bonanza inoculated at the five- to six-leaf stage and for Stylepak inoculated at the four- to six-, six- to seven-, and seven- to eight-leaf stages.

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