سمیت تماسی حشره کش های اکسی دیمتون متیل و تیاکلوپرید+دلتامترین روی حشرات بالغ زنبورعسل اروپایی (Apis mellifera L.)

Honey bee might be in contact with pollen and nectar contaminated with different insecticides during the flowering stage of plants.In this study, we aimed at assessing the contact toxicity of oxydemeton-methyl (Metasystox-R® EC %25)and thiacloprid+deltamethrin (Proteus® OD %11), on adult workers of honey bee (Apismellifera L.).To estimate the LC values, 1 mL of various concentrations of tested insecticides(commercial formulations) were applied to the filter papers (Whatman no. 1, 100 cm2), which were left to dry for 30 min at room temperature. Tap water was used as a solvent. These filter papers were used to cover the bottom of plastic dishes. After preliminary dose-setting experiments, bees were treated with estimated concentrations of the insecticides for 24 h. Logarithmic series of dilutions were offered to identify the effective range of concentrations causing 10–90% mortality. Each dish received a group of twenty0 to 24-hour-old adult workers of honey bee. Dimetoate (Rexion® EC %40) was used as the toxic standard and control bees were treated with tap water. All tests were arranged in a complete randomized design with four replications for each concentrationat 32±1°C and 60% relative humidity (r.h.) in darkness. In all treatments, the bees were provided ad libitum with freshly made sucrose-solution 50% (w/v) and mortality was recorded at 24 h post exposure. Our results showed that the LC50 value of oxydemeton-methyl, thiacloprid+deltamethrin, and Dimetoateestimated to be 268.24, 127.46and 262.15µg a.i./mL.Based on relative median potency estimates, oxydemeton-methyl and thiacloprid+deltamethrin were 1.00 and 2.11 folds more toxic than Dimetoateto honey bee. So, it is demonstrated that Metasystox-R® and Proteus®, which are among commonly used insecticides in Iran, might generate acute toxicity on honey bees.