Lee J. Ashworth, Jr., is Plant Pathologist, stationed at San Joaquin Valley Agricultural Research and Extension Center, Parlier; Santiago A. Gaona is Superintendent of Pistachio Production, Blackwell Land Company, Lost Hills; Arthur H. McCain is Plant Pathologist, U.C. Cooperative Extension, Berkeley. David P. Morgan is Research Associate, Plant Pathology Department, Berkeley, stationed at San Joaquin Valley Agricultural Research and Extension Center, Parlier;