Insecticidal and antifeedant activity of Melia azedarach (L.) fruits, on Spilosoma obliqua (Walker) (Lepidoptera: Arctiidae) larvae

The survivorship bioassay conducted with the M. azedarach fruit extracts on the first instar larvae showed a very high toxicity, most effective being methanol sequential fruit extract and this extract when tested on 4 th and 5 th instar larvae had significant antifeedant activity at all the concentrations.Nevertheless, there was less toxicity seen in the hexane extract test whereas, strong larvicidal activity of methanol sequential extract was observed with the neonate larvae reflects the higher susceptibility of neonate to this extract and thus indicating that to control the spread of this pest by targeting at the earlier stages.In addition, the results of the reduced leaf area consumed and fecal pellets excreted indicated that the high potency of the various extracts of M. azedarach, methanol sequential in particular, could be harnessed and its application would result in considerable reduction in the feeding damage by the pest.