AbstractsEngineering

Adequate control of the codling moth in the apple orchards of central Washington has become more difficult in recent years than ever before, in spite of improved spraying equipment and increased attention to control measures other than spraying. The work discussed herewith was begun in 1933 as a continuation ot previous efforts of the Washington Experiment Station to improve chemical methods of codling moth control, and in addition, to alleviate the difficulty of removing spray residues at harvest. Most of the expertments were carried on at Wenatchee, Washington, but the analyses of materials as well as some of the arsenical deposit determinations were made at the main station at Pullman, Washington. Since the most significant outcome of this work has been the development of the inverted spray mixture, in principle an innovation for the insecticide field, it appears to merit considerable discussion. The account which follows, therefore, in addition to a brief review of the literature concerning the materials in question, presents in some detail certain of the methods and results of the Wenatchee investigations. Because of the immediate need for practical information on the part of the Washington apple industry, it has not been possible to devote sufficient time to the laboratory part of the work. Some of the experiments could well bear repetition, and repetition might alter present concepts. [...]