Persistence and metabolism of the diamide insecticide cyantraniliprole in tomato plants

Plant uptake and metabolism of pesticides are complex and dynamic processes, which contribute to the overall toxicity of the pesticides. We investigated the metabolic fate of cyantraniliprole, a new diamide class of insecticide, during various growth stages of tomato. Cyantraniliprole was the major residue in leaves, flowers, and fruits, with the relative metabolite-to-parent ratios maintained at < 10% up to 28 days after treatment (DAT). Mature leaves contained consistently higher residues of cyantraniliprole than young leaves throughout the study. Flowers contained the highest cyantraniliprole residues up to 21 DAT, then gradually decreased. Immature green fruits had the highest cyantraniliprole residues (5.3 +/- 0.7 ng/g; 42 DAT), and decreased toward red ripening stages (1.4 +/- 0.2 ng/g; 84 DAT). Metabolism of cyantraniliprole primarily occurred in the foliage, where 21 metabolites were tentatively identified. Flowers and fruits contained 14 and four of these metabolites, respectively. Major transformation pathways were characterized by ring closure, followed by N-demethylation, and glycosylation. Additionally, plant metabolism of cyantraniliprole was also associated with several minor phase-I, phase-II, and breakdown metabolites. The occurrence of these metabolites in plants varied as a function of tissue types and their developmental stages. Our study highlights a tissue-specific biotransformation and accumulation of metabolites of cyantraniliprole in tomato.

Automated summary

The plant uptake and metabolism of the insecticide cyantraniliprole was studied in tomato plants, revealing that mature leaves contained the highest residues, followed by flowers and immature fruits. Metabolism of cyantraniliprole primarily occurred in the foliage, with various metabolites identified in flowers and fruits. Major transformation pathways included ring closure, N-demethylation, and glycosylation, with additional minor phase-I, phase-II, and breakdown metabolites also observed. Overall, there was a tissue-specific accumulation of metabolites of cyantraniliprole in tomato plants.