Contact Toxicity of O,O-Dimethyl 2,2,2-Trichloro-l-Hydroxyethyl Phosphonate and Its Acyloxy and Vinyl Derivatives, 1970-71

Abstract

Topical application tests of the contact toxicity of trichlorfon and a congeneric series of acyloxy and vinyl derivatives were conducted on last-stage western spruce bodworm. Except for the lower acyloxy derivatives, all acyloxy trichlorfon derivatives were synthesized by the slight excess (5%) of trichlorfon and freshly distilled acid chloride in refluxing benzene. After termination of the hydrogen chloride evolution, the benzene solution was washed with water to remove unreacted trichlorfon, dried with sodium sulfate, and the solvent removed to yield acyloxy trichlorfon. The lower acyloxy (C1 to C4) trichlorfon derivatives were synthesized by the reaction of acid anhydride with trichlorfon. After termination of the reaction, they were processed in the same way as the higher derivatives. Insects tested were from the 28th to 30th generations of a non-diapausing laboratory colony. Four concentrations serially diluted from a freshly prepared concentrate were used in each of 3 replications of each test. All chemicals were applied in reagent grade acetone. Treatment was performed with an ISCO model M micro-applicator equipped with a 1/4-cc tuberculin syringe. A dose of 1 μl/100 mg body weight was applied to the thoracic dorsa of CO2-anesthetized larvae weighing 70-110 mg. After treatment, larvae were fed artificial diet. Mortality was tallied after 7 days.