Abstract
Insects cause extensive damage to stored grains and their value added products. Among the stored grain pests Sitophilus oryzae (L.) Callosobruchus chinensis (Fab.) and Tribolium castaneum (Herbst.) are considered as destructive pests in India. Plants may provide alternatives to currently used insect control agents as they constitute rich source in bioactive molecules. Lantana camara, an erect shrub, which grows widely in the tropics, exhibits insecticidal activity against several insects. The methanol extract from leaves of L. camara has fumigant and contact toxicity against S. oryzae, C. chinesis and T. castaneum. In fumigant assays, The LC50 for S. oryzae was 128 μl/L(1), C. chinensis 130.3 μl/L(1), and T. castaneum 178.7 μl/L(1). The LD50 values for S. oryzae C. chinensis and T. castaneum in contact toxicity were 0.158, 0.140 and 0.208 mg/cm(2), respectively. For grain treatment, a concentration of 500 mg/L(1) and 7 days exposure were needed to obtain 90 - 100 % population extinction in all three insects. Probit analysis showed that C. chinensis were more susceptible than S. oryzae and T. castaneum. Gaschromatography-Mass Spectrometer (GCMS) studies for extracts indicated the presence of potent fumigant molecules in L. camara. The prospect of utilizing L. camara as potent fumigant insecticide is discussed.
Keywords:
Adult mortality; Callosobruchus chinensis; Fumigant and contact toxicity; Lantana camara; Sitophilus oryzae; Tribolium castaneum.