Tobacco Ringspot Virus from Squash Grown in South Carolina and Transmission of the Virus Through Seed of Smooth Pigweed. B. Sammons, Former Graduate Assistant, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29634-0377. O. W. Barnett, Professor, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29634-0377. Plant Dis. 71:530-532. Accepted for publication 19 January 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0530.

Tobacco ringspot virus (TRSV) was detected in commercial fields of yellow summer squash (Cucurbita pepo) in only one of seven South Carolina counties. TRSV was isolated from root tissue of smooth pigweed (Amaranthus hybridus) growing adjacent to diseased squash plants in the field and was shown to be seed-transmitted in this host. Xiphinema americanum was associated with diseased plants in the field, and Cucumis sativus ‘Model’ bait plants grown in field soil became infected with TRSV. The host range and serological properties of the isolate from squash were similar to those of other TRSV isolates; the isolate belongs to the NC-38 serogroup. Estimated relative molecular masses of the RNAs and protein of the squash isolate of TRSV were consistent with values reported for other TRSV isolates. This is the first report of TRSV from squash in South Carolina.