CHANDEL, R.P.S.THAKUR, AMITA2017-05-202017-05-202014http://krishikosh.egranth.ac.in/handle/1/5810011763ABSTRACT Intrinsic toxicity of insecticides namely fipronil, flubendiamide, chlorfenapyr, deltamethrin and indoxacarb was studied against 3 rd instar larvae of tobacco caterpillar, Spodoptera litura (Fabricius) in the laboratory of the Department of Entomology, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan (HP). Amongchemical insecticides, indoxacarb was the most toxic against the test insect with LC50 value of 0.0011 (fiducial limits: 0.0009 and 0.0014) followed by fipronil (0.0014 %) (fiducial limits: 0.0012 and 0.0017), chlorfenapyr (0.0024 %) (fiducial limits: 0.0019 and 0.0031), flubendiamide (0.0038 %) (fiducial limits: 0.0028 and 0.0050) and deltamethrin (0.0055 %) (fiducial limits: 0.0043 and 0.0069) percent. The respective LC 90values obtained were 0.0067 (fiducial limits: 0.0036 and 0.0124), 0.0053 (fiducial limits: 0.0037 and 0.0076), 0.0151 (fiducial limits: 0.0084 and 0.0269), 0.0272 (fiducial limits: 0.0134 and 0.0553) and 0.0336 (fiducial limits: 0.0202 and 0.0558) per cent. In case of botanicals, aqueous extracts of neem seed kernels and darek drupes resulted in dosage-dependent mortalityof eggs of S. liturawith LC50values of 4.0703 (fiducial limits: 3.2831 and 5.0464) and 4.4454 (fiducial limits: 3.7257 and 5.3041), and LC 90values of 35.7757 (fiducial limits: 19.9433 and 64.1770) and 29.1018 (fiducial limits: 19.8862 and 42.5880) per cent, respectively. Aqueous extracts of neem seed kernels and darek drupes exhibited strong antifeedant action against 3 rd instar larvae of S. litura as the caterpillar consumed only 21.6, 16.2, 11.4, 7.4 and 2.8 cm 2 and 21.8, 16.6, 13.8, 6.6 and 3.2 cm 2 leaf area when treated with 0.625, 1.25, 2.5, 5 and 10 and 1.25, 2.5, 5, 10 and 20 per cent concentrations of neem and darek extracts, respectively, as against 46.0 and 48.8 cm 2 in control treatments, respectively. These extracts at 0.25 and 0.5 per cent each also reduced the weight of 4 th and 6 th instar larvae developed from larvae treated during 3 rd instar significantly over control.ennullThesis