联苯菊酯在棉花和土壤中的残留和降解行为研究

为了评价为联苯菊酯在棉花上使用的安全性,于2010—2011年在济南、杭州两地采用田间试验和气相分析方法研究了联苯菊酯在棉叶、棉籽及土壤中的消解动态和最终残留。联苯菊酯在棉叶和土壤中的降解行为均符合一级降解动力学方程,其降解半衰期分别为4.2-6.7、10.6-16.0 d。联苯菊酯在棉籽和土壤中的最终残留质量分数均小于最低检出限0.01 mg.kg-1,低于联苯菊酯在棉花上的最高残留限量（MRL）0.5 mg.kg-1。建议10%联苯菊酯可溶液剂防治棉花蚜虫,用药次数1-2次,使用剂量是9-18 aig.hm-2,在棉花上的安全间隔期14 d。

The residue and degradation of bifenthrin in cotton and soil

To evaluate the safety in repeated annual field applications of the insecticide bifenthrin to cotton plants, the final residue and degradation dynamics of bifenthrin were studied in cotton leaves, seeds and corresponding soil, respectively, by collecting the samples from the trials both in Jinan and Hangzhou areas in 2010 and 2011. The chemical was analyzed by gas chromatography （GC） The degradation behavior of bifenthrin can be described by first-degree dynamic pattern in the cotton leaves and the soil. The half-lives of bifenthrin were 4.2---6.7 and 10.6-16.0 d, respectively. The residues in the cotton seeds and the soil were as low as below limit of detection （LOD） of 0.01 mg.kg-1, which were lower than the maximum residue limit （MRL） of 0.5 mg.kg-1. We suggest that 10% bifenthrin soluble concentrate liquid （SL） be used in cotton against Aphid with dosage 9-18 aig.hm2, and sprayed 1-2 times per season. The pre-harvest interval （PHI） is defined to be 14 days.