20％啶虫脒·哒螨灵微乳剂在棉花和土壤中的残留检测及消解动态分析

Residue Determination and Degradation Analysis of Acetamiprid·Pyridaben 20% Microemulsion in Cotton and Soil

[目的]对20％啶虫脒·哒螨灵微乳剂在棉花和土壤中的安全性进行评价，为该农药在棉花上的合理使用提供重要的科学依据。【方法】气相色谱-电子捕获检测器进行定量分析，研究啶虫脒、哒螨灵在棉籽、棉花叶和土壤中的残留及消解动态。【结果]2011、2012年在河南和浙江2地田间残留试验结果表明：啶虫脒在棉花叶和土壤中的消解半衰期分别为3．8—8．9、2．9—6．2d；哒螨灵在棉花叶和土壤中的消解半衰期分别为0．49～1．3、5．3—7．6d；不同采样间隔及施药次数，啶虫脒在棉籽中的最终残留量均≤0．005mg／kg，哒螨灵在棉籽中的最终残留量均≤O．01mg／kg。【结论】该药为低残留、易消解农药，建议20％啶虫脒·哒螨灵微乳剂防治棉花蚜虫，最高用药量30ga-i．／hm^2，最多施药2次，安全间隔期为15d。

[Aims] The aim was to assess the safety of acetamiprid＇pyridaben 20% microemulsion in cotton and soil, provide an important scientific basis for the rational use of the pesticides in the cotton. [Methods] Dissipation dynamics and residues of acetamiprid and pyridaben in cottonseed, leaf of cotton and soil was reported under field conditions, the acetamiprid and pyridaben were determined by GC-ECD. [Results] Residue analysis and degradation of acetamiprid and pyridaben in the field trials in Henan and Zhejiang Province were investigated in the years of 2011 and 2012. The results showed that the half-lives of acetamiprid in leaf of cotton and soil was 3.8-8.9 and 2.9-6.2 d respectively. The half- lives of pyridaben in leaf of cotton and soil was 0.49-1.3 and 5.3-7.6 d respectively. The final residues of acetamiprid and pyridaben in cottonseed were all ~〈0.005 and ~〈 0.01 mg/kg respectively in different sampling interval and application times. [Conclusions] Not detected residues and short half-life in cottonseed and soil suggested that acetamiprid and pyridaben are easily dissipated and low residues pesticides, so it could be safely used in cotton crops when the dosage below 30 g a.i./ha, and the spray time should not be more than 2 times, preharvest interval （PHI） should be 15 d.