A lignin‐coated nanopesticide delivery system reduces the risk of avermectin to the natural predator, Harmonia axyridis

BACKGROUND Nanopesticides are deemed to significantly reduce the adverse effects of traditional chemical pesticides on the environment and organisms, but scientific evidence is lacking to support this claim. RESULTS Herein, nano‐lignin ( LGN ) coated avermectin ( AVM @ LGN ) exhibited reduced toxicity to Harmonia Axyridis compared with AVM ( AVM : LC 50 = 8.940 mg/L, LC 30 = 6.305 mg/L; AVM @ LGN : LC 50 = 23.158 mg/L, LC 30 = 14.849 mg/L), while significantly enhancing its predatory ability, individual development, fecundity, and population growth. Meanwhile, its insecticidal activity against Megoura crassicauda did not differ significantly from that of AVM . Analysis of stress‐related enzymes activity revealed that AVM @ LGN induced a moderate physiological metabolic response in H. axyridis compared to AVM . Transcriptome diversity suggested that the gene expression levels among the different treatments shared a similar trend. Besides affecting the expression of genes involved in longevity regulation and insect hormone biosynthesis, AVM treatment also altered genes related to signal transduction and metabolic detoxification, whereas the differentially expressed genes ( DEGs ) induced by AVM @ LGN were mainly associated with the penetration resistance of H. axyridis . CONCLUSION In summary, we demonstrate that AVM @ LGN significantly relieved adverse effects of AVM posed to H. axyridis . These results provide a reference for future biosafety assessments of nano‐lignin coated pesticide formulations and offers theoretical support for the promotion and application of AVM @ LGN .