Toxicity evaluation of emamectin benzoate against tobacco caterpillar (Spodoptera litura) by three different assay techniques Birah Ajanta, Alpana, Singh Brijesh, Mahapatro G. K., Gupta G. P. Division of Entomology, Indian Agricultural Research Institute, New Delhi-110 012. Abstract Toxicity of emamectin benzoate, an avermectin semi-synthetic insecticide, was evaluated in the laboratory to determine its performance on three different larval stages (5, 7 and 9 -day old) of tobacco caterpillar, Spodoptera litura during 2007–08. Three type of assay techniques viz. leaf-dip, potter's tower and thin-film were used, taking three different formulations of emamectin benzoate and were compared with conventional one, cypermethrin, against the test-insect Median lethal concentrations (LC50) of the emamectin benzoate 1.9%EC against 5-day, 7-day and 9-day old larvae were recorded as 0.00005, 0.00017 and 0.0007%, respectively. Emulsifiable concentrates (EC, 1.9 and 5%) of emamectin benzoate outperformed the water-soluble granule (WSG, 5%) formulation, whereas, EC formulation of emamectin benzoate 1.9% EC was found better than 5% EC. Amongst test-methods, leaf-dip bioassay was suitable and sensitive for the test-insecticide, obviously for the fact that, emamectin benzoate is a stomach poison in addition to its contact mode of action. Top Key words Spodoptera litura, emamectin benzoate, formulations, leaf-dip, thin-film, potter's tower. Top |