Comparative susceptibility of Aphis gossypii Glover (Hemiptera: Aphididae) on cotton crops to imidacloprid and a novel insecticide cyproflanilide in China

As a key industrial crop, cotton contributes to the sustainable development of cotton production in China. The resistance of cotton aphids to a variety of commonly used pesticides has seriously threatened the safety of cotton industry. Cyproflanilide is a meta-diamide insecticide that has been proven to be effective against the cotton aphid Aphis gossypii Glover (Hemiptera: Aphididae). The baseline susceptibility of A. gossypii field populations to cyproflanilide needs to be determined to ensure the continued efficacy of this insecticide. Nineteen field populations of A. gossypii were collected from major cotton-producing regions of China in 2021, The susceptibilities of these populations to cyproflanilide were estimated using a leaf-dipping method in the laboratory. Imidacloprid was employed as a reference. The results indicated that cyproflanilide was highly toxic to all populations of A. gossypii, with LC50 values ranging from 0.475 mg/L to 2.955 mg/L. In contrast, all populations of A. gossypii exhibited high resistance levels to imidacloprid (LC50 values ranged from 10.5 mg/L to 10000 mg/L). Through the analysis of the logistic distribution model, we found that only 1.89 mg/L, of cyproflanilide was required to against 90% field populations of A. gossypii, while the imidacloprid need to reach 1600 mg/L. These results suggested that cyproflanilide possesses excellent efficacy to A. gossypii with the resistance to other types of insecticides. It is useful for the monitoring and management of A. gossypii resistance.