Residue and Safety of Tolfenpyrad Used in Tea Plantations

Degradation dynamics and food safety of residual Tolfenpyrad in the tea, Fuyun 6 (Camellia sinensis) , were studied in a field test in Fu′an, Fujian.The results showed that the residue concentrations in both fresh and baked tea leaves increased linearly with Tolfenpyrad applications in the concentrations of 54-270g·hm-2, and that the residues did not degrade significantly during the baking process.When the recommended application concentrations of Tolfenpyrad at 108, 162, or 216g·hm-2 for the month of May was applied, the initial residues ranged from 33.73mg·kg-1to 67.58mg·kg-1, and reduced to 20mg·kg-1 after 10 days.It fitted the firstorder kinetics, with a T1/2ranging from 4.02 dto 5.00 d.The residue level in teas was found significantly lower in May than September during ayear.The current safe application requirement on Tolfenpyrad was low.For the domestic market, the MRL was recommended to be 20mg·kg-1, and a pre-harvest time, 15 d.