Journal of Entomological Research

The interaction between thiamethoxam and honey bees, acute dermal and oral toxicities were determined against Apis mellifera and Apis cerana. Acute dermal toxicity tests by applying thiamethoxam solution (μL) dissolved in acetone on the dorsal side of thoracic region revealed median lethal dose (dermal; 24 h) as 93.97 ng g^-1 against A. mellifera where as, for A. c. cerana, it was 86.51 ng g^-1 with corresponding log likelihood ratio as 1.40 showing that both the values were at par with each other. In oral toxicity studies, starved honey bee foragers were fed with various concentrations of thiamethoxam in 50% sucrose water solution. Median lethal toxicity values at 24 h against A. mellifera and A. c. cerana were 67.61 and 31.43 ng g^-1, respectively. The log likelihood value of 2.78 showed there exists a significant difference among the two values i.e. A. c. cerana was more susceptible (Sensitivity ratio = 2.51) to thiamethoxam than A. mellifera. Values of median lethal toxicity for formulated product of thiamethoxam i.e. Actara^® were similar to technical grade (Relative toxicity 1.04 -1.06), which showed no synergism or potentiation due to formulation, hence laboratory results have field applicability.