Life Parameters and Physiological Reactions of Cotton Aphids Aphis gossypii (Hemiptera: Aphididae) to Sublethal Concentrations of Afidopyropen

Abstract

The massive and repetitive application of synthetic insecticides for the management of cotton pests results in the accumulation of resistance in Aphis gossypii Glover, a destructive pest worldwide. New chemistries are needed for pest management. Afidopyropen exhibits high efficacy against piercing-sucking pests and has been applied as a complementary alternative insecticide against aphids. This study was conducted to investigate the lethal and sublethal effects of afidopyropen on the life parameters and physiological responses of A. gossypii. Detoxifying enzyme activities and expression levels of P450 genes were compared after exposure to three generations of afidopyropen. Bioassay results indicate that afidopyropen possessed the highest toxicity, with a LC50 value of 0.30 mg/L. Sublethal concentrations (LC5 and LC10) caused adverse impacts on the F0 generation, reducing adult longevity and fecundity. A high concentration (LC10) also caused adverse effects on the F1 generation, while a low concentration (LC5) stimulated the fecundity. After continuous treatments with afidopyropen, the susceptibility decreased. GSTs and P450 were induced through sublethal concentrations; moreover, their activities in the F3 generation were higher than that in the F0 generation. Furthermore, the expression levels of 12 P450 genes in the F3 generation were higher than those in F0 generation. In conclusion, afidopyropen has excellent acute toxicity and continuous control effects on A. gossypii. GSTs and P450 may play important roles in the resistance of A. gossypii to afidopyropen.