Toxic and Synergistic Properties of Several Botanical Extracts against Larval and Adult Stages of the Mosquito, Anopheles pharoensis

Abstract

Ethanolic extracts of 12 plants, belonging to 10 families were screened for their efficacy against larvae and adults of the mosquito, Anopheles pharoensis. The larvicidal LC50 values were < 100 ppm (32.1–76.4 ppm) and Cichorium intybus > Azadirachta indica > Conyza aegyptiaca > Piper nigrum > Salix safsaf > Sonchus oleraceus. The LC50 value for adults was least in case of C. aegyptiaca (0.072 ppm) and highest for Punica granatum (0.159 ppm) extracts. Tested insecticides (chlorpyrifos, deltamethrin, flufenoxuoron, methomyl) showed LC50 values between 0.04–0.155 ppm for the larvae and 0.07–0.137 ppm for the adults. Combining botanical extracts with each other and/or with insecticides induced potentiating effects for the majority of bioassayed mixtures, against both mosquito larvae and adults. Specifically, the synergistic effect was much pronounced for mixtures of the insecticide methomyl with different botanical extracts. The RC50 values ranged between 0.084 g/50 cm2 for S. oleracues and 0.312 g/50 cm2 for C. intybus extracts. The overall results of the present investigation reveal the broad-spectrum toxic properties of the tested plant extracts against An. pharoensis