Effect of Three Neem Seed Kernel Extracts on Performance of Spodoptera litura (Fabricius, 1775) Under Laboratory Conditions

Larvae of Spodoptera litura (Fabricius, 1775) are voracious feeders and cause huge economic losses to various crops. Non-judicious use of chemical pesticides has led to development of insecticide resistance and environmental hazards as well. Neem has been proven as an effective, ecofriendly and economical botanical pesticide to manage the pest but the performance of S. litura larvae exposed to crude neem seed extracts has not been studied in detail. The purpose of present study was to examine the growth inhibitory sub-lethal and lethal effects of three different neem extracts on neonate larvae and identify the most effective extract and the concentration. Three neem seed kernel extracts (aqueous, methanolic and hexane extracts) were assayed against larvae of Spodoptera litura Fabr. using leaf-dip bioassay methodology. Extracts (0.5% to 4%) were tested by allowing neonate larvae to feed individually for 24 h, and then transferring to untreated leaves. Larvae were monitored throughout their life span until adult emergence. All three neem extracts exhibited insect growth inhibitory and toxic effects and adults presented a range of malformations, however, methanol extract was found to be the most potent at all concentration levels.