Toxicity of Some Pesticides to Predacious Arthropods in Ontario Peach Orchards

Abstract

DDT, parathion, and carbaryl experimentally applied in peach orchards were highly toxic to most insect and arachnid predators, including those most effective in controlling orchard mites. Azinphos-methyl appeared to be as toxic as parathion to predators in grower-sprayed orchards. Larvae of the chrysopid Chrysopa carnea Stephens and the syrphid Toxomerus geminatus (Say) were remarkably tolerant of DDT. The phytoseiid mite Typhlodromus caudiglans Schuster appeared to have developed a high degree of resistance to DDT in one orchard. Sulphur was appreciably toxic only to phytoseiids and the erythraeid Balaustium sp., and captan had little or no effect on any predator. Chemical and biological control of phytophagous mites in peach orchards cannot be integrated while the presently used insecticides are needed for the control of the oriental fruit moth, Grapholitha molesta (Busck).