Insecticidal activity of pyrethrum extract and its four insecticidal constituents against house flies. I.—Preparation and relative toxicity of the pure constituents; Statistical analysis of the action of mixtures of these components

Abstract

AbstractPyrethrins I and II and cinerins I and II were isolated from commercial pyrethrum extract by displacement chromatography and were also reconstituted from the naturally derived acids and alcohols. The samples of each constituent isolated from both sources had identical chemical and physical properties, and were of the same insecticidal potency within the limits of experimental error. The relative toxicities of the four constituents to female house flies (Musca domestica L.), determined at 20° by a measured drop technique, were: pyrethrum extract, 1.0; pyrethrin II, 1.3‐ 1.5; pyrethrin I, 0.9‐1.0; cinerin II, 0.5‐0.6; cinerin I, 0.4‐0.5. The insecticidal activity of a mixture of the four constituents was examined statistically for simple similar joint action, assuming that the probit‐log‐dose lines for the separate constituents were not parallel; the predicted results are in good agreement with the experimental data. The procedures for computing the responses predicted by simple similar joint action are discussed.