吡草醚在小麦和土壤中的残留及安全使用评价

Residue of Pyraflufen-ethyl in Wheat and Soil and Its Usage Safety Assessment

采用田间试验和气相色谱电子捕获检测器定量分析，对吡草醚在小麦及土壤中的残留消解动态及最终残留量进行了研究。消解动态试验结果表明：吡草醚在土壤中的半衰期为11．2～13．3 d，在小麦植株中的半衰期为5．6～6．8 d；最终残留量试验结果表明：吡草醚2％悬浮剂以12～18 g a．i．/hm2于小麦返青期施药1次，收获期小麦籽粒中吡草醚残留量均未检出（＜0．002 mg/kg），均未超过最高残留限量值0．02 mg/kg （ MRL）。该药在小麦返青期及以前施药，推荐吡草醚2％悬浮剂在小麦上使用安全间隔期为50 d。

A field experiment was conducted to reveal the residue digestion dynamic and final residual quantities of pyraflufen-ethyl in wheat and soil by GC with ECD .The digestion dynamic test results showed that the half-life period of pyraflufen -ethyl in soil was 11.2~13.3 days, and 5.6~6.8 days in plants.The final residue test results showed that spraying 2%pyraflufen-ethyl SC at the dosage of 12~18 g a.i./hm2 for one time at returning green stage , the final residual quantities in wheat grain were not detected , which were lower than the maximum residue limit （MRL） of 0.02 mg/kg.Therefore, 2%pyraflufen-ethyl SC should be sprayed at returning green stage or before , and the safety interval is suggested to be 50 days.