哒螨灵在棉花和土壤中的残留及消解动态研究

研究了哒螨灵在棉花和土壤中的残留及消解动态,采用气相色谱-电子捕获检测器进行定量分析。哒螨灵在棉籽、棉花叶及土壤中添加平均回收率为82.36%~113.94%,相对标准偏差为1.76%~8.07%。其最小检出量为1×10-11 g,在棉籽、棉花叶及土壤中的最低检测浓度均为0.01mg/kg。2011和2012年在河南省和湖南省的田间残留试验结果表明:哒螨灵在棉花叶中的消解半衰期为0.84~2.5 d,土壤中的消解半衰期为5.7~7.3 d;哒螨灵在棉籽中的最终残留量均≤0.01mg/kg,说明该药为低残留、易消解农药。建议采用10%哒螨灵微乳剂防治红蜘蛛,最高有效成分用量为112.5 g/hm2,最多施药3次,安全间隔期为14 d。

Study on Residue Analysis and Degradation of Pyridaben in cotton and Soil

Dissipation dynamics and residues of pyridaben in cotton and soil were reported, and pyridaben was determined by GC-ECD. The fortified recoveries in cottonseed, cotton leaf and soil at 0.01-0.2 mg/kg were 82.36%-113.94% with the relative standard deviations of 1.76%-8.07%. The limit of detection of the analytical method was 1×10-11 g at a signal-to-noise ratio of 3, and the limits of quantification were 0.01 mg/kg in cottonseed, cotton leaf and soil. The dissipation dynamics of pyridaben in Henan and Hunan Province were investigated in 2011 and 2012. The results showed that the half-lives of pyridaben were 0.84-2.5 d in cotton leaf, 5.7-7.3 d in soil. The final residues of pyridaben in cottonseed were all less than 0.01 mg/kg. Pyridaben is an easily dissipated and low residues pesticide, so it could be safely used in cotton with the maximum active ingredient dosage of 112.5 g/hm2, the spray times of 3, preharvest interval （PHI） of 14 d.