噻虫嗪在棉叶中残留消解动态及对棉蚜的防治效果评价

【目的】研究噻虫嗪种衣剂在棉叶中的消解动态,评价其对棉蚜的防治效果。【方法】采用QuEChERS-UPLC-MS/MS方法,定期测定棉叶中噻虫嗪的含量,田间调查噻虫嗪种衣剂对棉蚜防治效果。【结果】0.01~0.50 mg/L线性关系良好,相关系数r=0.999。在0.01、0.20、0.50 mg/kg添加水平下,噻虫嗪在棉叶中的平均回收率在93.4%~119.71%,相对标准偏差为0.34%~5.18%,方法检测限为0.001 mg/kg。噻虫嗪在棉叶中的消解动态符合一级动力学方程,半衰期为3.85~4.03 d。下部叶中噻虫嗪含量分别占各处理总浓度的59.42%~76.39%,噻虫嗪主要分布在下部叶片。出苗后30 d时,600 g/100kg处理防效最佳,仍可达87.90%。【结论】使用600 g/100kg浓度噻虫嗪种子处理,可较好地防治苗期蚜虫。

Degradation Dynamics of Thiamethoxam Residues in Cotton Leaves and Evaluation of Its Control Effect on Aphis gossypii Glover

【Objective】 To study the degradation dynamic of thiamethoxam seed treatment in leaves of cotton and evaluate the control effect of thiamethoxam seed treatment on Aphis gossypii by field experiment.【Method】 The content of thiamethoxam in cotton leaves was determined by QuEChERS UPLC MS / MS, and the control effect of thiamethoxam seed coating on cotton aphid was investigated in the field.【Results】 The results indicated that thiamethoxam had a good linear relationship in the range from 0.01 to 0.50 mg/L,r=0.999. At three spiked levels (0.01, 0.20 and 0.50 mg/kg), the average recoveries of thiamethoxam ranged from 93.4% to 119.71%, and the relative standard deviation ranged from 0.34% to 5.18%(n=5), the limit of detection was 0.001 mg/kg. The degradation kinetic of thiamethoxam in leaves of cotton was in accord with the first-order kinetic equation, and the half-life was 3.85-4.03 d. The concentration of thiamethoxam in the bottom leaves accounted for 59.4% to 76.39% of the total concentration of each treatment, so thiamethoxam was mainly distributed in the bottom leaves. The control effect of 600 g/100kg treatment was the highest, reaching 87.90% at 30 days after germination.【Conclusion】 Using 600 g/100kg thiamethoxam seed treatment can better control aphids in the seedling stage.