噻虫胺在黄瓜叶片中累积量与对温室白粉虱防治效果的相关性及残留消解动态

Correlation between the accumulation amount of clothianidin in cucumber leaves and the control efficacy on greenhouse whitefly and the dynamics of residue dissipation

通过探究18%噻虫胺包埋颗粒剂在黄瓜Cucumis sativus L.叶片中的累积量与其对温室白粉虱Trialeurodes vaporariorum Westwood防治效果的相关性及残留消解动态,以期为指导其科学用药,降低环境风险提供理论依据。以1%噻虫胺颗粒剂为对照药剂,通过温室黄瓜栽培试验,调查了18%噻虫胺包埋颗粒剂对温室白粉虱的防治效果。通过建立黄瓜叶片和土壤中噻虫胺残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)检测方法,测定了不同施药量和黄瓜不同生长时期条件下18%噻虫胺包埋颗粒剂在黄瓜叶片中的累积量,并研究了其累积量与防治效果的相关性。结果表明:18%噻虫胺包埋颗粒剂对温室白粉虱的防效为49%~95%,是对照药剂1%噻虫胺颗粒剂的1.16~2.32倍,且在推荐施药剂量(有效成分450 g/hm^(2))下即能达到理想防效;其在土壤中的残留消解动态符合一级反应动力学方程,消解半衰期为43~63 d,而对照药剂为35 d,表明其在土壤中的消解速率缓慢;噻虫胺在黄瓜叶片中的累积量随施药量的增加而增加,累积量与防效均随施药时间的推移呈现先升高后降低的变化趋势,并在施药后56 d达到最高值,当施药剂量有效成分分别为450、600和750 g/hm^(2)时,黄瓜上部叶片中噻虫胺的最大累积量分别为1.9、2.2和2.8 mg/kg,最高防效均为90%;中部叶片中噻虫胺的最大累积量分别为2.2、2.5和3.0 mg/kg,最高防效分别94%、93%和95%。

In order to provide theoretical basis for guiding scientific use of 18%clothianidin embedding GR and reducing environmental risk,the correlation between the accumulative amount and the control efficacy on whitefly of 18%clothianidin embedding GR and the dynamics of residual dissipation were investigated on greenhouse cucumbers.Under greenhouse conditions,using 1%clothianidin GR as the control agent,the control efficacy of 18%clothianidin embedding GR on whitefly was investigated.An ultra-performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS)method was established for the determination of clothianidin residues in cucumber leaves and soil.The accumulative amount of clothianidin in cucumber leaves at different application dosages and different growth stages was determined,and the correlation between the accumulative amount and control efficacy was studied.The results showed that the control efficacy of 18%clothianidin embedding GR on whitefly was 49%-95%,which was 1.16-2.32 times higher than that of 1%clothianidin GR,and the ideal control efficacy of 18%clothianidin GR granules could be achieved at 450 g a.i./hm^(2).The residue dissipation dynamic of clothianidin in soil was in accordance with the first-order kinetic equation.The half-life of 18%clothianidin embedding GR was 43-63 days,while that of 1%clothianidin GR was 35 days,which showed that 18%clothianidin embedding GR had a slow dissipation rate in soil.The accumulative amount of clothianidin in cucumber leaves increased with the increase of the dosage of 18%clothianidin embedding GR.Both the cumulative amount and the control efficacy on whitefly showed a trend of first increasing and then decreasing with the passage of the time after application,and reached the highest value on 56th days after application.When the application rates of active ingredients were 450,600 and 750 g/hm^(2),the maximum accumulation of clothianidin in upper leaves of cucumber were 1.9,2.2 and 2.8 mg/kg,respectively,and the highest control efficacy were all 90%.The maximum accumulation of clothianidin in middle leaves were 2.2,2.5 and 3.0 mg/kg,and the highest control efficacy were 94%,93%and 95%,respectively.