Gross Effects of Some Pesticides on Populations of Phytophagous Mites in Ontario Peach Orchards and Their Economic Implications

Abstract

Since 1946, a major project at the Vineland Station laboratory has been one on the indirect effects of pesticides on populations of injurious arthropods in peach orchards of the Niagara Peninsula. Plant-feeding mites have been the most readily affected. This paper describes the gross changes in mite populations produced by the pesticides and considers their economic importance and the possibility of reducing their injurious effects. The controversial problem of the means whereby some pesticides, particularly DDT, promote mite increase is still under study and will be treated in later papers.