Sublethal and transgenerational effects of spirodiclofen and cyenopyrafen on the life‐history traits and population parameters of Tetranychus urticae Koch (Acari: Tetranychidae)

BACKGROUND Tetranychus urticae Koch is an agricultural pest mite with a global distribution, high pesticide resistance, and a wide range of host plants. In this study, we examined the life‐history traits and population parameters of parental and progeny generations of T. urticae exposed to sublethal concentrations of spirodiclofen and cyenopyrafen. Our goal was to provide key information for the development of a local integrated pest management (IPM) program for field strains of T . urticae . RESULTS The fecundity, longevity, and oviposition days of T . urticae decreased at 10% and 30% lethal concentrations (LC 10 and LC 30 ) of spirodiclofen and cyenopyrafen. In addition, the transgenerational effects of spirodiclofen and cyenopyrafen reduced the net reproductive rate ( R 0 ), intrinsic rate of increase ( r ), finite rate of increase ( λ ), and survival rate of the progeny generation produced by females exposed to sublethal concentrations. However, the mean generation time ( T ) and developmental duration of the progeny generation were prolonged by sublethal concentrations of spirodiclofen and cyenopyrafen. CONCLUSION T . urticae may develop slowly at sublethal concentrations of spirodiclofen and cyenopyrafen and is unlikely to rebound. Therefore, sublethal concentrations of spirodiclofen and cyenopyrafen may be helpful in IPM. Overall, the study of sublethal effects on pests is crucial and should be considered when evaluating the effect of a toxicant.