Field responses of six processing pea cultivars to pea seedborne mosaic virus were tested in an isolated location near Prosser, WA, in 1977 and 1978. Test plots were mechanically inoculated either 2 or 3 wk after emergence. Disease incidence, determined visually on a per plant basis, was higher in all plots in 1977 than in 1978 and generally corresponded with rate of seed transmission and loss in green pea and seed yields. The later maturing, more determinate cultivars (Mars, Conway, and Corfu) were more severely affected than earlier maturing, indeterminate cultivars (Small Sieve Alaska and A-45) in both years. Losses in green pea and seed yields in 1977 were greater in plots of all cultivars inoculated 2 wk after emergence than in those inoculated 3 wk after emergence. Pea seedborne mosaic virus (PSbMV) is a continuing threat to the pea (Pisum sativum L.) seed and processing industry in the United States (12,17,20,22). This Contribution of AR, SEA, USDA, in cooperation with the Agricultural Experiment Stations,