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Ecology and Epidemiology

Occurrence and Overwintering of Cucumber Mosaic Virus and Broad Bean Wilt Virus in Weeds Growing Near Commercial Lettuce Fields in New York. D. L. Rist, Postdoctoral research associate, Department of Plant Pathology, New York State College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853; J. W. Lorbeer, professor, Department of Plant Pathology, New York State College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853. Phytopathology 79:65-69. Accepted for publication 19 July 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/Phyto-79-65.

Natural hosts of cucumber mosaic virus (CMV) and broad bean wilt virus (BBWV) near commercial lettuce fields in New York included 18 and four weed species, respectively. Inoculation of diagnostic hosts was useful in discerning whether weeds were infected in cases where results with enzyme-linked immunosorbent assay were borderline. There were no marked differences between the natural hosts of two strains of CMV commonly isolated from lettuce and designated as CMV-L1 and CMV-L2. CMV-L2 was slightly more common than CMV-L1 (55% vs. 45% of the total CMV-positive samples). Asclepias syriaca, Barbarea vulgaris, Rorippa islandica, and Linaria vulgaris all harbored CMV in subterranean structures throughout the winter. The rhizomes of L. vulgaris also served as overwintering sites for BBWV.

Additional keywords: epidemiology, Lactuca sativa.