Growth inhibitory and antifeedant activity of extracts from Melia dubia to Spodoptera litura and Helicoverpa armigera larvae.
The growth inhibitory activity and deterrency of Melia dubia (Meliaceae) extracts to Spodoptera litura and Helicoverpa armigera were investigated. Artificial diet bioassays using neonate larvae of both S. litura and H. armigera indicated that dichloroethane (DCE) and methanol (Me) extracts of M. dubia inhibited growth in a dose dependent manner. DCE and Me-5II fractions also resulted in 50% deterrency at concentrations of 22.5 and 16.8 micrograms/cm2 respectively against S. litura larvae in a leaf disc-choice test. The DCE-5 fraction was found to be more toxic to larvae (LC50 of 0.65%) than the Me-5II (LC50 of 0.8%), 72 hr after topical application. Both fractions lack contact toxicity, but the deterrent effect persisted for at least 60 hr under laboratory conditions. Although salannin was isolated from the DCE fraction to show antifeedant activity, the physico-chemical characteristics of the active fractions DCE-5 and Me-5II were not identical with either salannin or azadirachtin.
Insect Biopesticide Research Centre, 30 Parkash Nagar, Jalandhar, 144 003, India.
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Koul
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Jain
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VK
Sharma
D000085:Acetates; D000473:Alkanes; D000818:Animals; D005025:Ethylene Dichlorides; D005247:Feeding Behavior / Q000187:drug effects*; D006131:Growth Inhibitors / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D007194:India; D007306:Insecticides / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D007814:Larva; D000432:Methanol; D009036:Moths / Q000187:drug effects* / Q000254:growth & development; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D010944:Plants / Q000737:chemistry*; D012997:Solvents; D018411:Spodoptera / Q000187:drug effects* / Q000254:growth & development
D000085:Acetates; D000473:Alkanes; D005025:Ethylene Dichlorides; D006131:Growth Inhibitors; D007306:Insecticides; D010936:Plant Extracts; D012997:Solvents; C007650:ethyl acetate; C004544:naphtha; D000432:Methanol