吡虫啉和噻虫胺在甘薯中的分布动态及对甘薯蛴螬的防治效果

Distribution dynamics of imidacloprid and clothianidin in sweet potato plants and their control efficacy on white grubs

[目的]明确吡虫啉和噻虫胺在甘薯植株中的分布动态以及对甘薯蛴螬的防治效果。[方法]甘薯栽秧时穴施吡虫啉和噻虫胺颗粒剂,采用QuEChERS法结合超高效液相色谱-串联质谱法,在施药9、16、20、27、34、41、48、55、62、69、76、83、90、98、111 d后测定甘薯植株中药剂含量,甘薯收获时调查对甘薯蛴螬的防治效果。[结果]除在34 d(薯块形成初期)和90 d(薯块形成后期)外,吡虫啉和噻虫胺的含量在根中高于薯块、茎和叶片中。其余时期甘薯植株中吡虫啉和噻虫胺含量在根中最高。施药后41~48 d植株中各部位的含量达到最高,之后降低。土壤施用2%吡虫啉颗粒剂1500 g a.i./hm^(2)处理对甘薯蛴螬的防治效果为90.40%~92.37%,0.5%噻虫胺颗粒剂600 g a.i./hm^(2)为79.87%~80.44%,与900 g a.i./hm^(2)处理(84.93%~86.58%)差异不显著。[结论]土壤施用吡虫啉和噻虫胺后,甘薯根内药剂含量总体趋势高于其他部位。施用2%吡虫啉颗粒剂1500 g a.i./hm^(2)和0.5%噻虫胺颗粒剂600~900 g a.i./hm^(2)对甘薯蛴螬具有良好防效。

[Aims]This study aims to clarify the distribution dynamics of imidacloprid and clothianidin in sweet potato plants and their control efficacy against sweet potato grubs.[Methods]Imidacloprid GR and clothianidin GR were applied in the planting hole during the planting of sweet potato seedlings.The QuEChERS method,combined with ultra-performance liquid chromatography-mass spectrometry,was used to determine the contents of imidacloprid and clothianidin in sweet potato plants on days 9,16,20,27,34,41,48,55,62,69,76,83,90,98 and 111 after treatment.During the sweet potato harvest,the control efficacy of insecticides were evaluated.[Results]The content of the pesticides in the root was higher than that in theunderground stem and tuberous root-except on days 34(early stage of tuberous root formation)and 90(late stage of tuberous root formation)after treatment.It reached the highest amount on days 41 to 48,and then decreased.The control efficacy of imidacloprid 2%GR at the dosage of 1500 g a.i./ha was 90.40%-92.37%,while that of clothianidin 0.5%GR at 600 g a.i./ha was 79.87%-80.44%,which was not significantly different from that at 900 g a.i./ha treatment(84.93%-86.58%).[Conclusions]The content of pesticide in the root was higher than that in the other parts of the plant.The satisfactory control efficacy was achieved with the treatment of imidacloprid 2%GR at 1500 g a.i./ha and clothianidin 0.5%GR at 600-900 g a.i./ha.