Laboratory Screening of Insecticides for the Prevention of Reproduction of Boophilus Ticks

Abstract

Adult engorged females of Boophilus annulatus (Say) and B. annulatus microplus (Conestrini) were dipped in 3 or more concentrations of candidate compounds to determine the effects on reproduction. This laboratory screening procedure was used to establish the approximate comparative toxicity of 100 compounds. In general, B. a. microplus collected in Mexico in Tammaulipas were more susceptible to insecticides than B. anmulatus obtained in Coahuila. At concentrations of 0.001% to 0.01%, General Chemical 4072, 2-chloro-1-(2,4-dichlorophencyl) vinyl diethyl phosphate, was completely efflective in preventing hatching. The following compounds gave the same r esult at 0.01% to 0.1%: Bayer 29952, O -enthyl O -[ p- methylthio) phenyl] methylphonothioate; Bayer 30237, O [ p- (methylthio) methylphosphonothioate; Bayer 37341, O-[4-(methylthio)-3,5-xylyl]phosphorothioate; coumaphos; General Chemical 3582, 2,2-dichloro-1-(2,5-dichlorophenyl) vinyl diethyl phosphate; and lindane. The most promising compounds as inhibitors of oviposition were lindane; Stauffer R-3244, 2-(diethoxyphosphinothioyloxy)-ethyl dimethylcarbamate; and Telodrin®, 1,3,4,5,6,7,8,8-octachloro-1,3,3a,4,7,7a-hexahydro-4,7-methanoisobenzofuran. An attempt to increase the toxicity of Pyrolan,® 3-methyl-1-phenyl-5-pyrazolyl dimethylearbamate, by adding synergists was not successful, but in a single test dimetan waas apparently synergized by octachlorodipropyl ether.