(+)-Catechin from Prunus padus disrupts detoxification pathways and provides field-level control of the bird...

Plant-derived compounds, which act through diverse biochemical pathways, can be used for pest insect control to help reduce the risk of insecticide resistance. Here, we evaluated the insecticidal activity of (+)-catechin, isolated from Prunus padus, against the bird cherry-oat aphid (Rhopalosiphum padi), a major cereal pest worldwide. (+)-catechin significantly reduced aphid survival, with an LC₅₀ of 2.99 mg/L at 48 h, and suppressed reproduction, lowering total fecundity by 34% at sublethal doses. Sublethal exposure also shortened adult longevity and the reproductive period. Transcriptomic analyses revealed strong induction of detoxification-related genes, particularly UDP-glycosyltransferases (UGTs) and cytochrome P450s. Enzyme assays confirmed elevated P450 and UGT activity but reduced activities of glutathione S-transferase and ATP-binding cassette transporter, suggesting a dual mode of action that overwhelms detoxification capacity. RNA interference validated the key roles of RpUGT344D5 and RpCYP15A1, whose knockdown lowered LC₅₀ values by 76% and 39%, respectively, whereas RpCYP4CH8 knockdown had no effect. Field trials showed that foliar applications of (+)-catechin reduced aphid populations by up to 84%, with efficacy comparable to imidacloprid. Non-target assays indicated ≤5% mortality of the predator Harmonia axyridis. Taken together, these results demonstrate that (+)-catechin disrupts detoxification pathways and suppresses aphid population growth under both laboratory and field conditions, indicating it as a botanical insecticide candidate for integration into sustainable management of R. padi.