Influence of partially purified fractions of acetone extract of Acacia nilotica (L.) on development of Spodoptera litura (Fab.)

Environment and human health are being adversely affected because of the extensive use of chemical pesticides in the fields. These pesticides enter in the food chain resulting in their bioaccumulation at different trophic levels. Consequently biopesticides are being explored as new safer alternatives. Plant’s secondary metabolites such as phenolics play an important role in their defense against various insect pests. Phenolics in plants act as deterrent and feeding barriers to different insect pests. Their accumulation in different plant parts resist herbivory. In the present study, two partitioned fractions viz. ethyl acetate and water fraction, of acetone bark extract of Acacia nilotica (L.) were tested for their influence on the development of second instar larvae of Spodoptera litura (Fab.) (Lepidoptera: Noctuidae). Both fractions showed a toxic influence on larvae of S. litura but the effect was markedly greater with ethyl acetate fraction. The toxic effects were manifested in the form of increased larval mortality, reduced pupal weight, decreased adult emergence and prolongation in larval, pupal and total development period. Several deformities were observed in pupae and adults of S. litura. The findings indicated the anti insect potential of A. nilotica against S. litura.