Six experiments were conducted in 2018 on field sites located in Arkansas, Indiana, Michigan, Nebraska, Ontario, and Wisconsin to evaluate the off-target movement (OTM) of dicamba under field-scale conditions. The highest estimated percentages of dicamba injury in non–dicamba-resistant (DR) soybean were 55%, 44%, 39%, 67%, 15%, and 44% injury for noncovered areas and 55%, 5%, 13%, 42%, 0%, and 41% injury for covered areas during dicamba application in Arkansas, Indiana, Michigan, Nebraska, Ontario, and Wisconsin, respectively. The level of injury generally decreased as the downwind distance increased under covered and noncovered areas at all sites. There was an estimated 10% injury in non-DR soybean at 113, 8, 11, 8, and 8 m; and estimated 1% injury at 293, 28, 71, 15, and 19 m from the edge of treated fields downwind when plants were not covered during dicamba application in Arkansas, Indiana, Michigan, Ontario, and Wisconsin, respectively. Assessment of filter-paper collectors placed from 4 to 137 m downwind from the edge of the sprayed area suggested the dicamba deposition reduced exponentially with distance. The greatest injury to non-DR soybean from dicamba OTM occurred at Nebraska and Arkansas (as far as 250 m). Non-DR soybean injury was greatest adjacent to the dicamba sprayed area, but injury decreased with no injury beyond 20 m downwind or in any other direction from the dicamba sprayed area in Indiana, Michigan, Ontario, and Wisconsin. The presence of soybean injury under covered and noncovered areas during the spray period for primary drift suggests that secondary movement of dicamba was evident at five sites. Additional research is needed to determine the exact forms of secondary movement of dicamba under different environmental conditions.

中文翻译：

---

北美麦草畏脱靶运动评估

2018 年在位于阿肯色州、印第安纳州、密歇根州、内布拉斯加州、安大略省和威斯康星州的现场进行了六项实验，以评估麦草畏在现场规模条件下的脱靶运动 (OTM)。非麦草畏抗性 (DR) 大豆中麦草畏损伤的最高估计百分比为 55%、44%、39%、67%、15% 和 44%，非覆盖区域为 55%、5%、13%、在阿肯色州、印第安纳州、密歇根州、内布拉斯加州、安大略省和威斯康星州，麦草畏应用期间覆盖区域的伤害分别为 42%、0% 和 41%。在所有站点的覆盖和非覆盖区域下，随着顺风距离的增加，伤害程度普遍降低。非 DR 大豆在 113、8、11、8 和 8 m 处估计有 10% 的损伤；在 293、28、71、15、分别在阿肯色州、印第安纳州、密歇根州、安大略省和威斯康星州，当麦草畏施用期间未覆盖植物时，距离处理田地边缘顺风 19 m。对距喷洒区域边缘顺风 4 至 137 m 放置的滤纸收集器的评估表明，麦草畏的沉积随距离呈指数下降。麦草畏 OTM 对非 DR 大豆的最大伤害发生在内布拉斯加州和阿肯色州（最远 250 m）。非 DR 大豆在麦草畏喷洒区域附近的伤害最大，但在印第安纳州、密歇根州、安大略省和威斯康星州的麦草畏喷洒区域的下风向或任何其他方向超过 20 m 时，伤害减少了。在初级漂移的喷洒期间，覆盖和未覆盖区域下大豆损伤的存在表明麦草畏的二次移动在五个地点是明显的。需要进一步的研究来确定不同环境条件下麦草畏二次运动的确切形式。