Agronomic crops engineered with resistance to 2,4-D or dicamba have been commercialized and widely adopted throughout the United States. Because of this, increased use of these herbicides in time and space has increased damage to sensitive crops. From 2014 to 2016, cucumber and cantaloupe studies were conducted in Tifton, GA, to demonstrate how auxinic herbicides (namely, 2,4-D or dicamba), herbicide rate (1/75 or 1/250 field use), and application timing (26, 16, and 7 d before harvest [DBH] of cucumber; 54, 31, and 18 DBH of cantaloupe) influenced crop injury, growth, yield, and herbicide residue accumulation in marketable fruit. Greater visual injury, reductions in vine growth, and yield loss were observed at higher rates when herbicides were applied during early-season vegetative growth compared with late-season with fruit development. Dicamba was more injurious in cucumber, whereas cantaloupe responded similarly to both herbicides. For cucumber, total fruit number and relative weights were reduced (16% to 19%) when either herbicide was applied at the 1/75 rate 26 DBH. Cantaloupe fruit weight was also reduced 21% and 10% when either herbicide was applied at the 1/75 rate 54 or 31 DBH, respectively. Residue analysis noted applications made closer to harvest were more likely to be detectable in fruit than earlier applications. In cucumber, dicamba was detected at both rates when applied 7 DBH, whereas in cantaloupe, it was detected at both rates when applied 18 or 31 DBH in 2016 and at the 1/75 rate applied 18 or 31 DBH in 2014. Detectable amounts of 2,4-D were not observed in cucumber but were detected in cantaloupe when applied at either rate 18 or 31 DBH. Although early-season injury will more likely reduce cucumber or cantaloupe yields, the quantity of herbicide residue detected will be most influenced by the time interval between the off-target incident and sampling.

中文翻译：

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2,4-D和麦草畏低剂量施用对黄瓜和哈密瓜的影响

抗 2,4-D 或麦草畏的农作物已在美国商业化并广泛采用。正因为如此，这些除草剂在时间和空间上的增加使用增加了对敏感作物的损害。从 2014 年到 2016 年，在佐治亚州蒂夫顿进行了黄瓜和哈密瓜研究，以证明生长素除草剂（即 2,4-D 或麦草畏）、除草剂比率（1/75 或 1/250 田间使用）和施用时间（黄瓜收获前 26、16 和 7 天 [DBH]；哈密瓜 54、31 和 18 DBH）影响作物伤害、生长、产量和可销售水果中除草剂残留的积累。与果实发育后期相比，在早期营养生长期间施用除草剂时，观察到更大的视觉损伤、葡萄藤生长减少和产量损失率更高。麦草畏对黄瓜的伤害更大，而哈密瓜对两种除草剂的反应相似。对于黄瓜，当以 26 DBH 的 1/75 比率施用任一除草剂时，总果实数和相对重量减少（16% 至 19%）。当除草剂以 54 或 31 DBH 的 1/75 施用时，哈密瓜果实重量也分别减少了 21% 和 10%。残留分析指出，接近收获的应用比早期应用更容易在水果中检测到。在黄瓜中，当施用 7 DBH 时，两种施用率都检测到麦草畏，而在哈密瓜中，当施用 18 或 31 DBH 时，在 2016 年和 2014 年施用 18 或 31 DBH 时以 1/75 施用率检测到麦草畏。在黄瓜中未观察到 2,4-D，但在以 18 或 31 DBH 施用时在哈密瓜中检测到。