Evaluating Toxicity of Commonly Used Insecticides on Red Dwarf Honey Bee, Apis florea F. (Hymenoptera: Apidae)

The extensive use of insecticides has raised concern regarding their toxicological risk to honey bee species, Apis florea (Hymenoptera: Apidae). Bees may come into contact with pesticides while foraging in the field to gather nectar and pollen from agricultural blooming plants, which cause the death of their workers. In this respect, the current study was conducted to evaluate the toxicity of certain commonly used insecticides against the population of A. florea. The concentrations tested in the residual bioassays were 1, 2, 4, 8 and 16 ppm for abamectin, cypermethrin, imidacloprid, acetamiprid andpyriproxyfen, while for emamectin benzoate and carbosulfan, 0.125, 0.25, 0.5, 1 and 2 ppm. Each concentration was replicated three times. Our findings showed that the combination of emamectin benzoate and carbosulfan (LC₅₀ 0.54) was more toxic, followed by imidacloprid (LC₅₀ 0.70), acetamiprid (LC₅₀ 1.05), cypermethrin (LC₅₀ 1.57), pyriproxyfen (LC₅₀ 1.83) and abamectin (LC₅₀ 5.51). The present study shows the relative toxicity of various insecticides on A. florea besides the generalization that combinations of two insecticides (synergism) are more toxic to A. florea than a single insecticide. Therefore, combinations should be avoided for the management of insect pests.