In recent years, there has been increased use of dicamba due to the introduction of dicamba-resistant cotton and soybean in the United States. Therefore, there is a potential increase in off-target movement of dicamba and injury to sensitive crops. Flue-cured tobacco is extremely sensitive to auxin herbicides, particularly dicamba. In addition to yield loss, residue from drift or equipment contamination can have severe repercussions for the marketability of the crop. Studies were conducted in 2016, 2017, and 2018 in North Carolina to evaluate spray-tank cleanout efficiency of dicamba using various cleaning procedures. No difference in dicamba recovery was observed regardless of dicamba formulation and cleaning agent. Dicamba residue decreased with the number of rinses. There was no difference in dicamba residue recovered from the third rinse compared with residue from the tank after being refilled for subsequent tank use. Recovery ranged from 2% to 19% of the original concentration rate among the three rinses. Field studies were also conducted in 2018 to evaluate flue-cured tobacco response to reduced rates of dicamba ranging, from 1/5 to 1/10,000 of a labeled rate. Injury and yield reductions varied by environment and application timing. When exposed to 1/500 of a labeled rate at 7 and 11 wk after transplanting, tobacco injury ranged from 39% to 53% and 10% to 16% 24 days after application, respectively. The maximum yield reduction was 62%, with a 55% reduction in value when exposed to 112 g ha−1 of dicamba. Correlations showed significant relationships between crop injury assessment and yield and value reductions, with Pearson values ranging from 0.24 to 0.63. These data can provide guidance to growers and stakeholders and emphasize the need for diligent stewardship when using dicamba technology.

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麦草畏在喷雾罐中的滞留性评价及其对烤烟的影响

近年来，由于在美国引入了抗麦草畏的棉花和大豆，麦草畏的使用有所增加。因此，麦草畏的脱靶运动和对敏感作物的伤害可能会增加。烤烟对生长素除草剂极为敏感，尤其是麦草畏。除了产量损失外，漂流残留物或设备污染也会对作物的适销性产生严重影响。2016 年、2017 年和 2018 年在北卡罗来纳州进行了研究，以评估使用各种清洁程序对麦草畏的喷雾罐清洁效率。无论麦草畏配方和清洁剂如何，都没有观察到麦草畏回收率的差异。麦草畏残留量随着漂洗次数的增加而减少。从第三次漂洗中回收的麦草畏残留物与重新填充以供后续罐使用后罐中的残留物相比没有差异。3 次漂洗后，回收率在原始浓缩率的 2% 到 19% 之间。2018 年还进行了现场研究，以评估烤烟对麦草畏率降低的反应，麦草畏率从标记率的 1/5 到 1/10,000 不等。伤害和产量减少因环境和应用时间而异。在移植后 7 周和 11 周暴露于标记速率的 1/500 时，烟草损伤在施用后 24 天分别为 39% 至 53% 和 10% 至 16%。最大产量减少 62%，当暴露于 112 g ha 时，价值减少 55% 3 次漂洗后，回收率在原始浓缩率的 2% 到 19% 之间。2018 年还进行了现场研究，以评估烤烟对麦草畏率降低的反应，麦草畏率从标记率的 1/5 到 1/10,000 不等。伤害和产量减少因环境和应用时间而异。在移植后 7 周和 11 周暴露于标记速率的 1/500 时，烟草损伤在施用后 24 天分别为 39% 至 53% 和 10% 至 16%。最大产量减少 62%，当暴露于 112 g ha 时，价值减少 55% 3 次漂洗后，回收率在原始浓缩率的 2% 到 19% 之间。2018 年还进行了现场研究，以评估烤烟对麦草畏率降低的反应，麦草畏率从标记率的 1/5 到 1/10,000 不等。伤害和产量减少因环境和应用时间而异。在移植后 7 周和 11 周暴露于标记速率的 1/500 时，烟草损伤在施用后 24 天分别为 39% 至 53% 和 10% 至 16%。最大产量减少 62%，当暴露于 112 g ha 时，价值减少 55% 伤害和产量减少因环境和应用时间而异。在移植后 7 周和 11 周暴露于标记速率的 1/500 时，烟草损伤在施用后 24 天分别为 39% 至 53% 和 10% 至 16%。最大产量减少 62%，当暴露于 112 g ha 时，价值减少 55% 伤害和产量减少因环境和应用时间而异。在移植后 7 周和 11 周暴露于标记速率的 1/500 时，烟草损伤在施用后 24 天分别为 39% 至 53% 和 10% 至 16%。最大产量减少 62%，当暴露于 112 g ha 时，价值减少 55%-1麦草畏。相关性表明作物伤害评估与产量和价值降低之间存在显着关系，皮尔逊值在 0.24 到 0.63 之间。这些数据可以为种植者和利益相关者提供指导，并强调在使用麦草畏技术时需要认真管理。