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Ecology and Epidemiology

Relationships of Weed Reservoirs of Cucumber Mosaic Virus (CMV) and Broad Bean Wilt Virus (BBWV) to CMV and BBWV in 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 81:367-371. Accepted for publication 18 September 1990. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/Phyto-81-367.

The incidence of cucumber mosaic virus (CMV) and broad bean wilt virus (BBWV) in weeds within 10 m of commercial lettuce fields early in the growing season in New York correlated strongly with the incidence of the viruses in lettuce plants in the same fields later in the season (r = 0.93 for CMV and 0.88 for BBWV). Both viruses were more common (P = 0.025) in weeds within 10 m of lettuce fields than in weeds at distances between 20 and 40 m from the same fields. The 10-m distance always encompassed the drainage ditches that bordered the fields. These studies, conducted during the lettuce-growing seasons of 1984–1987, indicate that removal of weed hosts of CMV and BBWV growing on drainage ditch banks in and bordering commercial lettuce fields in New York would be a prudent practice in any attempt to manage the viruses.