Since the release of dicamba-tolerant cotton in 2016, preplant and POST applications of dicamba to control glyphosate-resistant Palmer amaranth have increased. With the increase in area treated with dicamba, the risk of off-target movement to nontarget crops has increased. A field study was conducted at the Texas Tech University New Deal Research Farm equipped with subsurface drip irrigation in 2017 and 2018 to evaluate non-dicamba tolerant cotton response to dicamba when applied at four crop growth stages [first square (FS) + 2 wk, first bloom (FB), FB + 2 wk, and FB + 5 wk]. Dicamba at 0.56 (1×), 0.056 (1/10×), 0.0112 (1/50×), 0.0056 (1/100×), and 0.00112 (1/500×) kg ae ha−1 was applied to ‘FM 1830GLT’ cotton. When applications were made at FS + 2 wk, a shift in boll nodal position was apparent following dicamba at the 1/50× rate in 2017 and at 1/10× in 2018 compared to the nontreated control (NTC). A shift in boll distribution from the 1/50× rate of dicamba was apparent at FB in 2017, but not in 2018. Dicamba applied at the 1× rate at FB + 2 wk resulted in reduced boll numbers. No change in boll number or boll position was apparent following any dicamba rate when applied at FB + 5 wk in both years. Dicamba applied at 1/500×, 1/100×, and 1/50× rates at all timings did not affect yield relative to the NTC. When dicamba was applied at the 1/10× rate, the greatest yield loss was observed at FS + 2 wk followed by FB and FB + 2 wk. Micronaire increased following dicamba applied at 1/10× at FS + 2 wk, FB, and FB + 2 wk in 2017. In 2018, micronaire decreased following dicamba applied at 1/10× at FB + 5 wk.

中文翻译：

---

麦草畏对敏感棉花结果的影响

自 2016 年推出耐麦草畏棉花以来，麦草畏在种植前和种植后用于控制抗草甘膦苋菜的应用有所增加。随着麦草畏处理面积的增加，脱靶运动到非目标作物的风险也增加了。2017 年和 2018 年在配备地下滴灌的德克萨斯理工大学新政研究农场进行了一项实地研究，以评估在四个作物生长阶段 [第一平方 (FS) + 2 周，第一次开花 (FB)、FB + 2 周和 FB + 5 周]。麦草畏在 0.56 (1×)、0.056 (1/10×)、0.0112 (1/50×)、0.0056 (1/100×) 和 0.00112 (1/500×) kg ae ha-1应用于“FM 1830GLT”棉。当在 FS + 2 周时进行应用时，与未处理的对照 (NTC) 相比，麦草畏 2017 年的 1/50 倍率和 2018 年的 1/10 倍率在麦草畏之后明显发生了棉铃节位置的变化。2017 年 FB 的棉铃分布从 1/50 倍的麦草畏比率发生了明显变化，但 2018 年没有。麦草畏在 FB + 2 周时以 1 倍比率施用导致铃数减少。在两年的 FB + 5 周施用麦草畏后，棉铃数或棉铃位置没有明显变化。在所有时间以 1/500×、1/100× 和 1/50× 的比率施用麦草畏并不影响相对于 NTC 的产量。当麦草畏以 1/10 倍的施用量施用时，在 FS + 2 周观察到最大的产量损失，其次是 FB 和 FB + 2 周。在 FS + 2 wk、FB、FB 以 1/10 倍施用麦草畏后，马克隆值增加