Spinetoram-based seed-pelleting with synergistic mixtures enhances control of the diamondback moth.

BACKGROUND: The diamondback moth, Plutella xylostella, is one of the most destructive pests of cruciferous crops worldwide. Its high fecundity, stress tolerance and seasonal migration often render traditional spray control ineffective. In this study, we propose an alternative method of controlling P. xylostella infestations using seed pelleting with spinetoram-based mixtures. RESULTS: Co-toxicity assays revealed that mixtures of spinetoram with acetamiprid (3:7), cyantraniliprole (5:5), and diafenthiuron (9:1) exhibited pronounced synergistic effects against P. xylostella larvae. The efficacy of radish seeds pelleted with the above combinations against P. xylostella and their impact on plant safety were evaluated under both controlled and field conditions. Spinetoram/acetamiprid (3:7) at the insecticide/seed ratios of 1:100 to 2.5:100, as well as spinetoram/cyantraniliprole (5:5) and spinetoram/diafenthiuron (9:1) at ratios of 0.25:100 to 2.5:100, did not affect seed germination and provided over 37 days of sustained high bioactivity against P. xylostella under controlled conditions. Field experiments demonstrated that pelleted seeds coated with spinetoram mixtures significantly reduced P. xylostella infestation for up to 45 days after sowing. Spinetoram provided immediate protection during the early seedling establishment stage (0-21 days), while cyantraniliprole or diafenthiuron ensured sustained control at the later seedling stage. CONCLUSION: Our study provides an effective solution for the control of P. xylostella, and demonstrates that seed pelleting with spinetoram mixtures can be a promising method for pest management in cruciferous crops. © 2026 Society of Chemical Industry.