Insecticidal and Acaricidal Activity of Certain O,O-Dialkyl O-3-Pyridazinyl Phosphorothioates

Forty-three 3-pyridazinyl phosphorothioates were evaluated for insecticidal and acaricidal activities against two-spotted spider mite, turnip aphid, smaller brown planthopper, mosquito larvae and American cockroach. Approximate acute oral toxicity of these compounds in mice was also examined. In general, the toxicity in mice was in parallel with the pesticidal activity, but a few compounds clearly showed a high degree of selectivity between pests and mice. Especially O,O-dimethyl O-(6-cyclohexyloxy-3-pyridazinyl)phosphorothioate showed substantially reduced mammalian toxicity but maintained high insecticidal and acaricidal activity.