Sublethal effects of flonicamid on the population growth of the grain aphid Rhopalosiphum padi (L.) (Hemiptera: Aphididae).

Abstract

Rhopalosiphum padi is an important grain pest, causing severe losses during crop production. As a systemic insecticide, flonicamid can control piercing-sucking pests efficiently. In our study, the lethal effects of flonicamid on the biological traits of R. padi were investigated via a life table approach. Flonicamid is highly efficiently toxic to R. padi, with an LC₅₀ of 9.068 mg L^-1. The adult longevity and fecundity of the R. padi F₀ generation were markedly reduced under the LC₂₅ and LC₅₀ concentrations of flonicamid exposure. In addition, negative transgenerational effects on R. padi were observed under exposure to lethal concentrations of flonicamid, with noticeable decreases in the reproductive period, adult longevity, total longevity, and total fecundity of the F₁ generation under the LC₂₅ concentration of flonicamid. Furthermore, the third nymph stage (N3), preadult stage, duration of the adult pre-reproductive period, duration of the total pre-reproductive period, reproductive period, adult longevity, total longevity, and total fecundity of the F₁ generation were significantly lower under treatment with the LC₅₀ concentration of flonicamid. The life table parameters were subsequently analysed, revealing that the intrinsic rate of increase (r_m) and the net reproductive rate (R₀) were significantly lower but that the finite rate of increase (λ) and the mean generation time (T) were not significantly different under the LC₂₅ and LC₅₀ concentrations of flonicamid. These data are beneficial for grain aphid control and are critical for exploring the role of flonicamid in the integrated management of this key pest.