噻虫嗪种子包衣对燕麦蚜虫和红叶病的控制效果及农药残留分析

Control Efficiency of Oats Seed-coating with Thiamethoxam on Aphids and Red Leaf and Analysis of Pesticide Residue

红叶病是由蚜虫传播黄矮病毒(BYDV)引起的燕麦上的重要病害,有效防治蚜虫可控制燕麦红叶病的发生。为了明确噻虫嗪种衣剂的应用效果和安全性,通过田间试验研究了噻虫嗪种子包衣对燕麦蚜虫和红叶病的防效及持效期,并采用高效液相色谱法测定了药物在植株和籽粒上的残留动态。结果表明,种子包衣处理后,燕麦单株蚜量和红叶病病情指数均低于对照,苗期至拔节期的蚜虫防效为77.71%～87.91%,红叶病防效为65.79%～82.89%;孕穗期至扬花期的蚜虫防效为58.45%～68.61%,红叶病防效为62.98%～64.14%,持效期长达90 d,可实现一次施药减轻蚜虫为害、控制红叶病的效果。残留分析表明,噻虫嗪种衣剂在燕麦植株中的残留动态符合一级动力学方程C=13.218e-0.0971t,半衰期为7.14 d,播种后60～100 d残留量为0.43～9.86 mg·kg-1,接近或超过了现有的草料MRLs值,此时不宜作为青饲料;播种110 d以后残留量≤0.06 mg·kg-1,可刈割青饲料或作为干草贮存使用。在燕麦籽粒中未检测到噻虫嗪。

The red leaf of oat caused by yellow dwarf virus（BYDV） is an important disease and it could be prevented by controlling of aphids.The control effects and efficacy duration of oat seeds coated with thiamethoxam on aphids and red leaf were investigated in the field.The dynamic of residue in plants and seeds were detected using high performance liquid chromatography（HPLC）.The results showed that both the aphid number on each plant and disease index of red leaf were lower in the plants of seed coating treatment than those of control.During seedling to jointing stage,the control effects on aphids were 77.71%～87.91% and the control effects on red leaf were 65.79%～82.89%.During booting to flowering stage,the control effects on aphids were 58.45%～68.61% and the control effects on red leaf were 62.98%～64.14%.So the efficacy duration was as long as 90 days.The residue dynamic of thiamethoxam residue in plants was accorded with the first-order dynamic equation C=13.218e-0.0971t based on the thiamethoxam residue 9.86 mg·kg-1 at the 60th day after planting,and the half-life period was 7.14 d.The thiamethoxam residue in plants were 0.43～9.86 mg·kg-1 at 60～100 d after planted,it was close to or exceeded the maximum residue limits（MRLs） for forage,so the plants could not be mowed as green feed.The residue was less or equal to 0.06 at 110 d after planted and could be mowed as green feed or hay.The thiamethoxam residue was not detected in oat kernels.