Toxicity of Nine Insecticides to Adult Tribolium castaneum (Herbst)

Nine insecticides were used in a toxicity test on adult red flour beetle, Tribolium castaneum (Herbst). Mortality tests were done by applying different doses of insecticide following residual-film method in a petridish on laboratory reared 3 to 7 days adults and the data was recorded after 24 hours of treatment. The calculated LD50 values were 13.8221, 53.8803, 8.0592, 424.1043, 223.2351, 8.1755, 920.1590, 243.3920 and 0.2416 μg/cm2 for chlorpyrifos, fenitrothion, malathion, monocrotophos, phosphamidon, carbosulfan, propoxur, cypermethrin and lambda-cyhalothrin respectively. The results indicate that lambda-cyhalothrin was the most toxic and propoxur was least toxic to adult red flour beetles when applied singly. The order of toxicity of the insecticides was lambda-cyhalothrin > malathion > carbosulfan > chlorpyrifos >fenitrothion > phosphamidon> cypermethrin> monocrotophos > propoxur. Lambda-cyhalothrin, malathion, carbosulfan and chlorpyrifos can be used to control red flour beetle in storage and other insecticides can control them moderately.