Uptake, Translocation, and Metabolism of Pydiflumetofen in Hydroponic Cucumber and Tomato Planting Systems

As a novel succinate dehydrogenase inhibitor (SDHI), pydiflumetofen (PYD) exhibits broad-spectrum bactericidal activity in various crops; however, little is yet known about its absorption, translocation, and metabolic behavior within plants. Cucumber and tomato plants were cultured in hydroponic conditions spiked at 0.5 mg/L of PYD, and samples were collected at certain intervals to investigate the residual fate of PYD within the plants. The results demonstrated that PYD was readily absorbed by the roots of both plants, with mean root concentration factors (RCFs) of 5.6–12.3 for cucumber and 5.0–12.4 for tomato. PYD exhibited higher translocation ability from stems to leaves and limited from roots to stems in cucumber, while comparably weak root-to-stem and stem-to-leaf translocation were observed in tomato. By the end of the exposure period, a mass loss of 51.55% and 56.67% was observed, and six and three metabolites were found to be generated in the cucumber and tomato systems, respectively. This study provides a foundation for comprehending the uptake and translocation of PYD and offers novel insights into its potential risks to agricultural products and food safety.