A Survey of Viruses Infecting Yellow Summer Squash in South Carolina. B. Sammons, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29634-0377. O. W. Barnett, R. F. Davis, and M. K. Mizuki. Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29634-0377, and Department of Plant Pathology, Cook College, New Jersey Agricultural Experiment Station, New Brunswick 08903. Plant Dis. 73:401-404. Accepted for publication 1 December 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0401.

A statewide survey of yellow summer squash was conducted to determine the incidence of cucumber mosaic virus (CMV), papaya ringspot virus W (PRSV-W, formerly watermelon mosaic virus 1), watermelon mosaic virus 2 (WMV-2), squash mosaic virus (SqMV), and tobacco ringspot virus (TRSV). Squash samples were collected during the summer and fall of 1981 and 1982 in seven counties where commercial squash is grown. Virus detection methods included gel double-diffusion and enzyme-linked immunosorbent assay tests. Samples consisted of two or three leaves near the shoot apex. Some were collected from diseased plants and others were taken at random without regard for disease status. Viruses found (highest to lowest number of infected fields) were WMV-2, CMV, PRSV-W, and TRSV; SqMV was not detected. WMV-2 occurred in higher incidence than the other viruses, with 100% infection found in one field in Greenville County. Random samples were not tested for zucchini yellow mosaic virus (ZYMV), but it was identified for the first time in South Carolina from plants in three counties. ZYMV was purified and identified on the basis of host range, serology, morphology, and aphid transmission. The symptomatology of these ZYMV isolates was similar to the Connecticut biotype of this virus.