Acute contact toxicity of neonicotinoids against Indian bees

Abstract

Studies were conducted to assess the acute contact toxicity of neonicotinoids against Indian bees at Department of Agricultural Entomology, Tamil Nadu Agricultural University, India. Imidacloprid, acetamiprod, thiacloprid, thiamethoxam, clothianidin and dinotefuran were used for the study. Bioassay experiments were carried out to determine the median lethal concentration (LC50) values and safety indices for A. cerana indica. The results reveal the LC50 values for the tested neonicotinoids were 32.26, 54.27, 96.86, 30.61, 40.31 and 103.28 ppm and the safety indices calculated on the basis of recommended spray concentration against the LC50 value were 0.81, 1.36, 1.61, 0.61, 1.01 and 2.07 respectively, for imidacloprid, acetamiprid, thiacloprid, thiamethoxam, clothianidin and dinotefuran. According to the safety index, thiamethoxam, followed by imidacloprid, are the least safe to bees.