Relative toxicity of insect growth regulators against tobacco caterpillar, Spodoptera litura (Fabricius)

Against third instar LC50 values based on bioassay studies indicated that among the insect growth regulators, viz., buprofezin, lufenuron, novaluron and the check diflubenzuron the highest relative toxicity was exhibited by novaluron at 76 hours and lufenuron at 96 and 120 h of exposure by topical application. novaluron exhibited greater toxicity irrespective of the time of exposure when sandwich method was used and Lufenuron was intermediary in toxicity.