The Contact Toxicity of Some Pesticide Residues to Hymenopterous Parasites and Coccinellid Predators1

Abstract

Sixty-one pesticides were tested in the laboratory against 5 parasitic hymenopterans and 6 predatory coccinellids, the data to serve as guides for selecting the best materials for destroying pests without undue harm to natural enemies. Test species were exposed in replicated tests to day-old residues of the pesticides under standardized conditions of dosage, temperature, and humidity. The single dosages applied were those most commonly used upon orchard crops. A table presents toxicity levels for each material and natural enemy species in conjunction with a rating of the persistence of each pesticide’s toxic residue. The data suggest that the effect of each pesticide upon most kinds of adult parasitic Hymenoptera may be anticipated with a high degree of reliability while the effect upon predatory coccinellids is much less predictable. The materials are discussed with respect to their specificity and the probable impact that their field usage might have upon parasitic Hymenoptera and predaceous Coccinellidae.