吡唑醚菌酯在梨中的残留动态分析

Residue and Dissipation Dynamics of Pyraclostrobin in Pear

为探究吡唑醚菌酯在梨中的残留降解情况,为生产上安全用药提供理论依据,于2020年在山东、河北、湖北、甘肃和安徽5省6地进行吡唑醚菌酯在梨上的残留田间试验。结果表明,吡唑醚菌酯在梨中的消解动态符合一级反应动力学方程,在梨中的半衰期为9.9 d。按稀释1 000倍液和500倍液,施药2、6次,于距离最后一次施药7、14和21 d采样,吡唑醚菌酯在梨中的残留量为0.001~3.601 mg/kg。高浓度施药后,6地样品均有超标现象。低浓度施药后,21 d采集的样品有超标现象,其他均未超标。说明在梨上施药时,应严格控制施药浓度、施药次数、采摘安全间隔期等农药标签要求,不能盲目增加施药次数,以免出现农药残留超标。

In order to investigate the residual degradation of pyrazolin in pears and provide theoretical basis for safe drug use in production,field experiments were conducted in Shandong,Hebei,Hubei,Gansu and Anhui provinces in 2020 to investigate the residual degradation of pyrazolin in pears.The results showed that the dissipation equations of pyraclostrobin in pear samples fit the first-order kinetics equation.The half-lives in pear was 9.9 d.The pyraclostrobin was sprayed by dilution of 1000 times and 500 times on pear for 2-6 times and samples were collected 7,14 and 21 d after the last application.The final residue of pyraclostrobin in the pear was 0.001-3.601 mg/kg.After applying high concentration,samples from 6 regions had exceeded the standard in some cases.After low-concentration application,except the samples collected at 7 and 14 days,the samples at 21 days exceed the standard.It was suggested that pesticide labeling requirements such as pesticide concentration,application times and pre-harvest interval should be strictly controlled when applying pesticide on pears,and the application times should not be blindly increased to avoid excessive standard.