两种喷雾助剂对噻虫嗪防治豇豆上蓟马的减施增效作用

为探索有机硅助剂Silwet stik和植物油助剂迈丝对噻虫嗪防治豇豆上蓟马Megalurothrips usitatus的效果及其残留行为的影响,通过田间试验,比较了25％噻虫嗪水分散粒剂(WG)在登记剂量和减量10％、20％、30％条件下分别添加两种助剂后5 d和7 d的防效,以及施药后噻虫嗪及其代谢物噻虫胺在豇豆...

Synergistic effect of two spray adjuvants on thiamethoxam in the control of Megalurothrips usitatus in cowpea

Organosilicon adjuvant Silwet stik and vegetable oil adjuvant Maisi were selected to conduct field experiments with thiamethoxam to verify the preventive effect on cowpea thrips and residual behavior. Dissipation dynamic and residues of recommended application dose 75, 67.5, 60, and 52.5 g a.i/hm2 of 25% thiamethoxam water dispersible granules (WG) with two different adjuvants were compared respectively and the preventive effect of 5 and 7 days after the last spray was investigated. The cowpea samples were extracted by acetonitrile, purified with primary secondary amine (PSA), and detected using high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The results of field tests indicated that the initial deposition of thiamethoxam on cowpea were significantly increased by 8.84% and 6.58% respectively when the adjuvant 0.4% Silwet stik or 0.5% Maisi was added. The control effect against cowpea thrips of 25% thiamethoxam WG added with the two adjuvants above were significantly higher than that without adjuvant 7 days after treatments. Five days after treatments, the addition of adjuvant Silwet stik or Maisi increased preventive effect by 4.04%-8.55% and 10.37%-12.25% respectively, while the recommended application dose of thiamethoxam was reduced by 10%-30%. The results showed that the adjuvant treatments increased the deposition of thiamethoxam on cowpea, which would benefit the synergistic effect of pesticide, and improved control effect on thrips. The study provides evidence for the synergistic control effect of adjuvants and the scientific use of thiamethoxam against cowpea thrips.