Abstract
The aim to plan this investigation was to evaluate insecticidal activities of three essential oils extracted from locally grown plants, Melia azadarach, Datura stramonium and Azadirachta indica at various concentrations viz., 5%, 10%, 15% along with phosphine gas at a dose rate of 100, 200, 300 ppm and their combinations against the grubs of Trogoderma granarium. Results depicted considerable toxicity of essential oils and phosphine gas alone which was considerably increased when test insects were exposed to the combination of these two. In essential oil alone assay, D. stramonium showed highest mean mortality of 31.99% at maximum concentration (15%) after 72h of exposure. While 57.63% mean mortality was observed against phosphine with 300 ppm of concentration after 72h. Combined application of essential oil (%) and phosphine (ppm) significantly increased mean mortality such as 86.47% (300ppm + 15% D. stramonium), 83.03% (300ppm + 15% A. indica) and 76.24% (300ppm + 15% M. azadarach) after 72h of exposure. Results regarding mortality were found to be directly related to concentration and exposure time.