Bioassay of Insecticides against Three Honey Bee Species

1 Entomological Research Institute, Ayub Agricultural Research Institute, Faisalabad, Pakistan 2 University of Agriculture, Faisalabad, Pakistan ABSTRACT. A study was conducted at the Eco-toxicology laboratory in the Department of Agricultural Entomology, University of Agriculture Faisalabad, against three species Apis florea, A. dorsata and A. mellifera of honey bees, to check long-term survival of honeybees when exposed to different insecticides. In this study, we used a modeling approach regarding survival data of caged bees under chronic exposure to seven insecticides (Carbosulfan, Chlorpyrifos, Bifenthrin, Spinosad, Indoxacarb, Emamectin benzoate and Imidacloprid), having three replicates and four concentrations (1000, 500, 250, 125 and 0 ppm). We demonstrate the chronic toxicity induced by these insecticides. Laboratory bioassay of these insecticides showed that carbosulfan and imidacloprid were the most toxic at their high dose (1000 ppm) with LT50 of 4 hours in each case for A. mellifera, chlorpyrifos and imidacloprid were the most toxic at their high dose (1000 ppm) with LT50 of 5 hours in each case for A. florea whereas chlorpyrifos was the most toxic at high dose (1000 ppm) with LT50 of 5 hours for A. dorsata. However, LT50 of spinosad was increased up to 18 hrs with decreasing concentrations at 125 ppm against A. mellifera, LT50 of spinosad was increased up to 15 hrs with decreasing concentrations at 125 ppm against A. florea as well as LT50 of spinosad and Emamectin benzoate was increased up to 20 hrs with decreasing concentrations at 125 ppm against A. dorsata. However, LT50 of all controlled species was 91-103 hrs.