Variable conditions in the fruit growing areas of California make it difficult to project the results from evaluation tests in one area to another. As a consequence, field plots were established for the 1957 season in Bartlett pear orchards—in Sacramento, Solano, El Dorado, Lake, and Mendocino counties—for University personnel to evaluate spray materials under local conditions. As a correlative evaluation, spray chemicals used in codling moth and aphid control plots were checked for their effects on spider mites.

Gordon Morehead, Sacramento County, Jim DeTar, Solano County, Dick Bethell, El Dorado County, Russell Gripp, Lake County, and Bruce Bearden, Mendocino County; Farm Advisors, University of California, cooperated in trials with Bartlett pears.