Trans-generational effects of spinetoram on biological traits of Spodoptera frugiperda

Spodoptera frugiperda (J.E. Smith) is the invasive pest of maize (Zea mays L.) and spinetoram is the novel insecticide used mainly against lepidopteran pests. The experiment was conducted during 2022, 2023 and 2024 at ICAR-Indian Agricultural Research Institute, New Delhi to comprehend the sub-lethal and trans-generational effects of spinetoram (Delegate® 11.7% sc) at LC10 and LC25 against S. frugiperda. The leaf dip bioassay findings indicated that spinetoram exhibited notable toxicity with the LC50 of 0.157 ppm. Exposure of sub-lethal doses of spinetoram on parental generation (F0) revealed that there are trans-generational deleterious effects on biology and lifetable parameters of S. frugiperda where the adverse effects were significantly hampering in the F0 and F1 whereas the F2 generation was found to be free of it. LC 10 and LC 25 of spinetoram significantly diminished biological attributes including rate of pupation, adult hatching, fecundity, longevity of adult, weight of larval and pupa and concurrently increased deformed adults and the duration of the larval and pupal stages. The lifetable parameters such as net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ) were decreased significantly in F0 and F1 generations. Moreover, these sub-lethal doses of spinetoram had significant decreased nutritional indices and considerably increased detoxification enzymatic activities like C-P450 and GST. It is inferred that, spinetoram exerted deleterious sub-lethal and trans-generational effects on the S. frugiperda population by impairing its survival, development and reproduction.