The Addition of Dicamba to POST Applications of Quizalofop-p-ethyl or Clethodim Antagonizes Volunteer Glyphosate-Resistant Corn Control in Dicamba-Resistant Soybean
Two studies consisting of six field experiments each were conducted at three locations in southwestern Ontario, Canada, in 2014 and 2015 to evaluate the possible antagonism when dicamba was added to quizalofop-p-ethyl or clethodim for the control of volunteer glyphosate-resistant (GR) corn. At 4 wk after application (WAA), quizalofop-p-ethyl at 24, 30, or 36 g ai ha(-1) provided 88, 94, and 95 control of volunteer GR corn, respectively. The addition of dicamba at 300 or 600 g ae ha(-1) to quizalofop-p-ethyl (24 g ha(-1)) reduced the activity of quizalofop-p-ethyl on volunteer GR corn by 12 and 20. At 4 WAA, clethodim at 30, 37.5, and 45 g ai ha(-1) provided 85, 91, and 95 control of volunteer GR corn, respectively. The addition of dicamba at 300 or 600 g ha(-1) to clethodim (30 g ha(-1)) resulted in antagonism, causing a reduction in volunteer GR corn by 12 and 11, respectively. In general, there was greater antagonism when the high rate of dicamba was tank-mixed with the lower rate of the graminicide. There was no antagonistic effect on soybean yield by tankmixing dicamba with either graminicide at all rates evaluated. Based on these results, volunteer GR corn can be controlled effectively by increasing the rate of the graminicide when tankmixed with dicamba.
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机译：2014 年和 2015 年在加拿大安大略省西南部的三个地点进行了两项研究，每项研究包括六个田间实验，以评估将麦草畏添加到喹唑草酯-p-乙基或烯草酮中以控制自愿抗草甘膦 （GR） 玉米时可能产生的拮抗作用。在施用后 4 周 （WAA） 时，24、30 或 36 g ai ha（-1） 的 quizalofop-p-ethyl 分别提供了 88%、94% 和 95% 的志愿者 GR 玉米控制。在quizalofop-p-ethyl（24 g ha（-1））中添加300或600 g ae ha（-1）的麦草畏可使志愿者GR玉米上quizalofop-p-ethyl的活性降低12%和20%。在4 WAA时，30、37.5和45 g ai ha（-1）的烯草酮分别对GR玉米的控制率为85%、91%和95%。在烯草酮（30 g ha（-1））中添加300或600 g ha（-1）的麦草畏导致拮抗作用，导致GR玉米的自愿减少分别减少12%和11%。一般来说，当高浓度的麦草畏与低剂量的禾本科杀虫剂混合时，拮抗性更大。在所有评估的速率下，将麦草畏与任何一种禾本科杀灭剂混合对大豆产量没有拮抗作用。基于这些结果，当与麦草畏混合时，通过提高禾本科杀灭剂的用量，可以有效地控制GR玉米。
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