Incidence of External Seedborne Verticillium albo-atrum in Commercial Seed Lots of Alfalfa. A. A. Christen, Research Associate, Department of Plant Pathology, Washington State University, Irrigated Agriculture Research and Extension Center, Prosser 99350. Plant Dis. 67:17-18. Accepted for publication 20 April 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-17.

Verticillium albo-atrum was detected on up to 2% of alfalfa (Medicago sativa) seed in commercial seed lots. The pathogen was found in 5 of 20 seed lots assayed from the Columbia Basin of Washington in 1979 and in 2 of 20 seed lots in 1980, respectively. The occurrence of external inoculum could be a factor in disease spread.