Toxicity of ready-mix formulations of Pyrethroids and ad-mixed insecticides on forager honey bee, Apis cerana indica fabricius*

Laboratory studies on forager honey bee, Apis cerana indica were carried out by using the contact filter paper technique to assess the acute toxicity of four ready mix formulations viz., endosulfan 32% + deltamethrin 0.8% (Decidan, 32.8 EC), acephate 25% + fenvalerate 3% (Koranda, 28 EC), chlorpyriphos 50%, + cypermethrin 5% (Nurelle D-505, 55 Ec), and triazophos 35% + deltamethrin 1% (Spark, 36 Ec) alongwith seven individual comprising ad-mixed insecticides. The LC50 values for Decidan, Konanda, Nurelle D and Spark were found to be 0.01462, 0.002354, 0.0014903 and 0.004306 %, respectivelly while the values for endosulfan, acephate chlorpyriphos, triazophos, deltamethrin, fenvalerate and cypermethrin were 0.040123, 0.01362, 0.0009789, 0.002189, 0.0003238, 0.008443 and 0.0004493%, respectively. Relatively safe ones for field use were judged on the basis of computed safety indices wherein, all the formulations were predicated to be safer except acephate, chlorpyriphos and Koranda which were predicated to be slightly toxic Nurelle D to be toxic.