LAUSR

BACKGROUND Tea is one of the most popular drinks in the world. The growth of tea plant is inseparable from the control of pesticides on diseases and pests. Pyriproxyfen is used as a pesticide substitute to control insect pests in tea gardens, but little is known about its residue degradation. Here, we performed an integrative study of the degradation and metabolism of pyriproxyfen from the tea garden to the cup. RESULTS The dissipation half-life of pyriproxyfen during tea growth was 2.74 d, and five metabolites PYPAC, PYPA, DPH-Pyr, 5"-OH-Pyr, and 4'-OH-Pyr were generated. The total processing factors for pyriproxyfen in green tea and black tea were 2.41-2.83 and 2.77-3.70, respectively. The residues of pyriproxyfen and its metabolites were affected by different processing steps. The total leaching rates of pyriproxyfen from green tea and black tea into their infusions were 9.8%-12.3% and 5.3%-13.8%, respectively. The leaching rates of the five metabolites were higher than that of pyriproxyfen and increased the intake risk. CONCLUSION To ensure safe consumption, the recommended maximum residue limit (MRL) value of pyriproxyfen in tea can be set to 5 mg kg-1 and the pre-harvest interval to 5 d. This article is protected by copyright. All rights reserved.