Prune russet scab, sometimes called lacy scab, was reduced to an insignificant level in the 1967 season by one application of a fungicidal spray during the full bloom period. Both Captan and Phygon (dichlone) proved successful and may be used by prune-growers. Difolatan (folcid), another chemical used in these tests, is not registered for use on prunes and should not be applied to prune trees.

Farm advisors D. H. Chaney, A. Retan, and F. Perry, as well as agricultural chemical representatives B. Reines, B. Hanke, E. Keegan, and F. Latoures, assisted in this study. The California Prune Advisory Board, Chevron Chemical Company—Ortho Division, and FMC Corporation—Niagara Chemical Division gave financial and material assistance. Determinations of russet scab percentages were made through the cooperation of Sunsweet Growers, Inc.