The standardized residual field trials of pyraclostrobin 250 g/L EC in winter jujube were carried out in Huanghua,in 2021-2022.The samples were extracted and purified by QuEChERS,and detected by GC-ECD.Then the residue degradation rule of pyraclostrobin in winter jujube was obtained,and the dietary risk assessment was conducted.The residue degradation tests showed that the half-lives of pyraclostrobin in winter jujube were 9.86 d,11.80 d,and the degradation dynamics accorded with the first-order reaction dynamic equations.The final residues were 0.297-0.684 mg/kg,at the 14-28 d after the last dose.The STMR of the 21 d was 0.432 mg/kg and the risk quotient was 0.62％,the dietary risk of pyraclostrobin was acceptable.It was suggested that pyraclostrobin 250 g/L EC was used in winter jujube with a dose of 3 000-4 000 times,the maximum application time was 3,the application interval was 7 d,and the pre-harvest interval was 21 d.
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