Evaluation of Toxicity of Few Novel Insecticides Against Different Aphid Species (Rhopalosiphum maidis, Myzus persicae, Liphaphis erysimi)

Aphids are important insect pests and are considered a major threat to various crops. In the laboratory experiment, our objective is to assess the toxicity level of some newer synthetic insecticides, viz. Imidacloprid, Flonicamid, and Spirotetramat against different species of aphids viz. maize leaf aphids (Rhopalosiphum maidis), green peach aphids (Myzus persicae), and mustard aphids (Liphaphis erysimi). The leaf dip bioassay was conducted to evaluate the LC50 and LT50 values. Among these novel molecules, Spirotetramat was the most toxic insecticide against R. maidis and M. persicae, with median lethal concentrations (LC50) of 0.68 and 3.99 ppm, and Flonicamid was the most toxic against L. erysimi with an LC50 value of 5.79 ppm. The median lethal concentrations for the Imidacloprid, Flonicamid, and Spirotetramat are different for each species of aphids. The LT50 values of the given insecticides revealed that the Imidacloprid has the potential for giving effective control of R. maidis, M. persicae, and L. erysimi species, as evidenced by the shorter time required for 50% mortality with LT50 values of 44.53, 49.19 and 44.90 hrs respectively with median lethal concentrations of 4.20, 5.14 and 10.86 ppm. The results indicated variations in toxicity among these different chemicals against different insect species.