Larvicidal potential of some plant extracts against Anopheles arabiensis Patton (Diptera: Culicidae)

Insecticide based vector control intervention is threatening with the emergence and spread of resistant vectors. The development of other eco-friendly and cost effective vector control tools is required to alleviate this problem. In this study, five selected plant leaf extracts were evaluated for their larvicidal activities against 3rd instar An. arabiensis larvae at concentrations ranging from 50 to 300 ppm following the WHO protocol. The best performing extract was subjected to bioassay-guided column chromatographic fractionation and all fractions were tested separately for their larvicidal activities. All the plant extracts were found to have potential larvicidal activities against 3rd instar An. arabiensis larvae. Methanol crude extract of Calpurnia aurea achieved 100% larval mortality at 300 ppm with LC50 of 84.85 ppm while less activity was observed for methanol crude extract of Artemisia annua, 68% larval mortality at 300 ppm. Column chromatographic fractions F1and F3 of methanol extract of C. aurea caused 100% mortality at 250 and 300 ppm with LC50 of 62.51 and 82.33 ppm, respectively. The present study revealed that column chromatographic fractions F1 and F3 of methanol extract of C. aurea caused a remarkable larvicidal activity against An. arabiensis demonstrating a high potential for botanical mosquito insecticide development.