Uptake and translocation of fungicide picarbutrazox in greenhouse cabbage: the significance of translocation factors and home processing.

This study evaluated the uptake and translocation of the fungicide picarbutrazox (PBZ) and its isomer in greenhouse cabbage. Two distinct treatments, including foliar spray and soil application of PBZ, were used in this study. In the foliar application, the fungicide was sprayed thrice at intervals of 7 days from 30, 21, and 14 days before harvest following the OECD guidelines of fungicides in crops, whereas in soil treatment, PBZ was applied for one time at concentrations of 2 and 10 mg/kg, and cabbage was cultivated for 68 days. Additionally, the role of root and translocation factors during residual fungicide distribution was demonstrated. The quality control of the analytical study exhibited excellent linearity (R2 ≥ 0.99), the limit of quantification (LOQ 0.005 mg/kg), accuracy (recovery within the range of 70-120%), and precision (relative coefficient within 0.3-13.8%) for studied PBZ and its metabolites. In the foliar application, initially higher amount of residual PBZ was evident in the outermost leaf of the cabbage, whereas in soil treatment, the highest residual PBZ was observed in the soil and roots. Therefore, the application method of picarbutrazox is a critical factor for defining the initial entry route of pesticides and the subsequent translocations through the investigated crops.

Dissipation characteristics of spirotetramat and its metabolites in two phenotypically different Korean vegetables under greenhouse conditions.

This study involved analysis and method validation of spirotetramat applied to two phenotypically different Korean vegetables (e.g. Korean cabbage and shallots) to determine the safe pre-harvest residue limit (PHRL) and comparative dissipation patterns. Two steps of the investigation involved greenhouse monitoring during crop cultivation followed by LC-MS/MS analysis. Commercial spirotetramat was sprayed twice with seven-day intervals according to the spray schedule (0, 3, 7, 10, 14, and 21 days before harvest) at the dose recommended by the Ministry of Food and Drug Safety (MFDS), Korea. During the validation of the analytical method, good linearity, specificity, and acceptable recoveries (82%-114% for Korean cabbage and 82%-111% for shallot) were established for spirotetramat and its four metabolites. The calculated biological half-life derived from the first-order reaction (t1/2) of spirotetramat was 4.8 days for Korean cabbage and 4.0 days for shallot, respectively. The safe PHRL for Korean cabbage was suggested at 7 days, due to permissible spirotetramat concentration in terms of an acceptable MRL. The findings of the study will be used as the analytical reference point for developing spirotetramat safety guidelines for use in the vegetables investigated.