Synergistic Action of Lemongrass Oil and Permethrin on Biochemical Responses of 𝑆𝑝𝑜𝑑𝑜𝑝𝑡𝑒𝑟𝑎 𝑓𝑟𝑢𝑔𝑖𝑝𝑒𝑟𝑑𝑎 (J.E. Smith)

Fall armyworm (FAW), scientifically known as Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae) is one of the major maize pests in Egypt and the strategies of management largely depend on application of different insecticides. However, resistance to these insecticides has been reported. Plant essential oils (EOs) are well known to act as biopesticides. This research evaluated the toxicity and synergistic effect of EOs from lemongrass (Cympobogon citratus) leaves in combination with permethrin against FAW by topical application method in the laboratory condition. Chemical characterization by the GC-MS analytical technique demonstrated that the lemongrass EO was composed of ۲۲ compounds, α-citral (۴۲.۸۶%) and β-citral (۳۶.۸۳%) were chosen as the major constituents. In larvicidal bioassays, EO of α-citral and β-citral were effective in killing FAW larvae, with LD۵۰ values of ۴.۷۹ and ۶.۳۰ μg/larvae, respectively. Synergistic assays reveal that α-citral and β-citral decreased the LD۵۰ values of permethrin against larvae drastically from ۱۰.۰۵ to ۰.۴۲ and ۰.۵۷ μg/larvae, respectively, with synergism ratio (SR) values of ۲۳.۹۳ and ۱۷.۶۳, respectively, with co-toxicity factor (CTF) values of +۳۵.۳ and +۲۶.۹, respectively. After exposure to the low lethal dose (LD۲۵) of α-citral and β-citral with permethrin, the activity of glutathione-S-transferase (GST), general esterases (ESTs), and cytochrome P۴۵۰ (P۴۵۰) was inhibited, which could explain their synergistic effect. Based on these results, the use of these mixtures represents an ideal eco-friendly approach, helping to manage permethrin resistance of FAW.

کلیدواژه ها:

Essential oils ، Detoxification enzyme ، Sublethal effect ، Synergist ، permethrin