Intergenerational effect of cyproflanilide at sublethal level to Chilo suppressalis (Walker) (Lepidoptera: Pyralidae)

Abstract

Rice stem borer (RSB) Chilo suppressalis Walker, is a globally voracious pest of the rice crop and has resistance against various insecticides. It is exciting that the novel meta-diamide insecticide cyproflanilide has demonstrated high efficacy against RSB. Therefore, the intergenerational sublethal effects on the parental (F₀) and the subsequent offspring (F₁) generation were further explored by using the age-stage TWOSEX-MS Chart program in this study. The bioassay results showed the LC₅₀, LC₃₀, and LC₁₀ of 0.046 mg/kg, 0.035 mg/kg, and 0.024 mg/kg, respectively after 96 h. For the biological parameters, the larval duration was prolonged by 1.84 d and 1.43 d in the LC₃₀ groups of the F₀ and F₁, respectively, while the mean female pupal weight, pupation rate, and emergence rate were significantly decreased in both generations. The mean fecundity was reduced by 20.5 and 10.96 eggs/female in the LC₃₀ groups of the F₀ and F₁, respectively. Meanwhile, a non-significant difference was observed in the population parameters, but the mean generation time (T) significantly increased by 1.21 d for the LC₃₀ group in the F₁ generation. The relative fitness (R_f) costs were 0.64 for LC₁₀ and 0.70 for LC₃₀ in the F₀ generation, while 0.85 for LC₁₀ and 0.76 for LC₃₀ in the F₁ generation. These findings highlight the potential of sublethal concentrations (LC₁₀ and LC₃₀) of cyproflanilide to alter key biological and population parameters of RSB, providing valuable insights for its integrated pest management program (IPM) in the field.