Nitenpyram, Dinotefuran, and Thiamethoxam Used as Seed Treatments Act as Efficient Controls against Aphis gossypii via High Residues in Cotton Leaves

The effects of eight neonicotinoid seed treatments against the cotton aphid Aphis gossypii and its natural enemies in Bt cotton fields were evaluated, and the concentrations of these neonicotinoids in cotton leaves and soil were also investigated. The results showed that all neonicotinoid seed treatments efficiently reduced A. gossypii populations throughout the cotton seedling stage. The percentages of curly leaf plants in all of the neonicotinoid seed treatments were below the threshold for economic loss. Among the eight tested neonicotinoid seed treatments, nitenpyram, dinotefuran, and thiamethoxarn showed high control efficiency against A. gossypii. Residues of the three neonicotinoids were higher than those of other neonicotinoids in cotton leaves. Moreover, residues of dinotefuran and nitenpyram remained at low levels in the soil. However, the abundance of natural enemies in the cotton field was to some extent influenced by neonicotinoid seed treatments. Therefore, neonicotinoids nitenpyram, dinotefuran, and thiamethoxam used as seed treatment can provide effective protection that should play an important role in the management of early-season A. gossypii in Bt cotton fields; however, the risks of neonicotinoids to the environment should also be considered.