Natural Virus Infection in Silvery and Nonsilvery Lines of Cucurbita pepo. Robert F. Davis, Department of Plant Pathology, Forestry, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick 08903. Oved Shifriss, Department of Horticulture and Forestry, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick 08903. Plant Dis. 67:379-380. Accepted for publication 3 September 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-379.

A silver-leaved breeding line, NJ260, and a green-leaved cultivar, Early Prolific Straightneck (EPS), of summer squash (Cucurbita pepo) were compared for virus disease development under natural conditions. Severity of disease was consistently lower in NJ260 than in EPS throughout the season. About 6 wk after planting, 99% of EPS and 28% of NJ260 plants showed symptoms of infection by cucumber mosaic virus and clover yellow vein virus (formerly the severe strain of bean yellow mosaic virus). By the end of the season, all plants of both lines had developed symptoms, although EPS plants were much more severely affected. Disease-related survival was 96% in NJ260 until the first frost, whereas in the EPS plants, deaths began at midseason, and at the last reading before frost, only 19% of the plants were alive.