Growth-disrupting, larvicidal and neurobehavioral toxicity effects of seed extract of Seseli diffusum against Aedes aegypti (L.) (Diptera: Culicidae)

Abstract

Plant extracts that kill, deform the post-embryonic molting stages of mosquitoes could be a valuable approach in integrated vector management programmes to replace synthetic chemical pesticides, containing persistent toxic substances. Crude ethanolic seed extract was obtained by maceration of seeds of Indian celery, Seseli diffusum (Apiaceae). The ethanolic seed extract induced strong neurobehavioral toxicity against the 4th instar larvae of Aedes aegypti which resulted in a high level of larval knock-down with EC(50) of 238.15 ppm, after 4h of treatment. The extract at concentration of 200 ppm exhibited a potent larvicidal effect against 4th instar A. aegypti, produced 88% and 96% mortality, after 24 and 48 h of treatment with LC(50) of 126.13 ppm and LC(50) of 112.53 ppm, respectively. The ethanolic seed extract at higher concentration (>400 ppm) produced 100% mortality, after 24 h and 48 h of treatment. At lower concentration of 100 ppm, extract induced a high level of morphological deformities in larvae, after 48 h of treatment. A high level of growth and/or molting disrupting effect of extract against larvae was also observed which resulting in the formation of larval-pupal intermediates, after 48 h of treatment. At concentrations of 200-300 ppm, ethanolic seed extract induced morphological deformities in dead pupae, after 72 h of treatment. The results showed that S. diffusum is a promising candidate for the development of new botanical biopesticide having multiple potentials for controlling insect pest of medical and agricultural importance.