Sweetpotato seeds in the early 1960s commonly carried feathery mottle virus, the cause of russet crack disease. In 1961, UCCE farm advisor Bob Scheuerman and specialist Dennis Hall began to test seeds for the virus and plant only clean seeds in their trial plots. By 1966 they were able to see significant increases in yield. Their testing and sorting methods are still used by growers today, and have contributed to increasing yields in California from 5 tons per acre in 1967 to 16.3 tons in 2009. Scheuerman and Hall’s seed tests are now used throughout California and in other states, helping provide more consistent, higher-quality sweetpotatoes for the market.