Establishment of Toxicity and Susceptibility Baseline of Broflanilide for Aphis gossypii Glove

SIMPLE SUMMARY: The control of Aphis. gossypii has relied on the application of insecticides, but the resistance to insecticides has become a key factor in the successful management of A. gossypii. It is a critical measure to introduce a novel insecticide with a different action mode in the resistance management. We found that broflanilide has high insecticidal activity against A. gossypii. Broflanilide susceptibility was determined in field populations of A. gossypii from main cotton planting areas of China. Meanwhile, the susceptible baseline of the cotton aphid to broflanilide was established. These results suggested that the cotton aphid possessed high susceptibility to broflanilide. The susceptible baseline provides a comparative basis for the future resistance monitoring in the management of cotton aphids. ABSTRACT: The Aphis gossypii is an important pest that can damage cotton plants and can cause a huge economic loss worldwide. Chemical control is a main method to manage this pest, but the cotton aphid resistance to insecticides has become a severe problem in the management of the cotton aphid. It is important to introduce a novel insecticide for rotational application with other insecticides. Broflanilide, as a meta-diamide insecticide with a special mode of action, showed high efficiency against lepidopterous larvae. However, we found that broflanilide possessed high insecticidal activity against the sap-sucking pest A. gossypii. The susceptibility of A. gossypii to broflanilide from 20 field populations in main cotton planting areas of China in 2021 was determined by the leaf-dipping method. LC(50) values of broflanilide to A. gossypii ranged from 0.20 μg mL(−1) to 1.48 μg mL(−1). The susceptible baseline of A. gossypii to broflanilide was established with the LC(50) value of 0.41 μg mL(−1) and might be used to calculate the resistance ratio (RR) of cotton aphid population in broflanilide resistance monitoring. The RR value of field populations in China was from 0.49 to 3.61 in 2021. It suggested that the broflanilide may be a potential agent in the resistance management of A. gossypii to insecticides. These results are significantly useful for the rational chemical control of cotton aphids.