Insight into the Fate of the Novel SDHI Pesticide Flubeneteram in Cucumber: Multiposition Carbon-14 Labeling Assistance

Flubeneteram is a new type of SDHI fungicide. This study simulated the application of pesticides in the field and used carbon-14 isotope tracing to investigate the absorption, transport, and accumulation of flubeneteram in its registered cucumber crop. Most of the flubeneteram residue remains on cucumber stems and leaves throughout spraying, and a very small portion can be transported to cucumber roots and fruits. Qualitative and quantitative analyses of highly specific metabolites of ¹⁴C-flueniferam in cucumber tissues were conducted via high-performance liquid chromatography–quadrupole time–of–flight (HPLC–QTOF-MS) with two different labeled positions, and their metabolic pathways were elucidated. In the leaves and stems, flubeneteram undergoes phase I and II metabolism, resulting in the production of a total of four metabolites. The proportions and concentrations of these four metabolites met the residual standards. Moreover, only two metabolites are present in cucumber fruit, and their proportions and concentrations also met the residue standards. Overall, our research findings provide relatively accurate predictions for the risk assessment of flubeneteram, which can guide its rational use and ensure its ecological safety and human health.