Tolpyralate is a new 4-hydroxyphenyl-pyruvate dioxygenase (HPPD)–inhibiting herbicide for weed control in corn. Previous research has reported efficacy of tolpyralate + atrazine on several annual grass and broadleaf weed species; however, no studies have evaluated weed control of tolpyralate + atrazine depending on time-of-day (TOD) of application. Six field experiments were conducted over a 2-yr period (2018, 2019) near Ridgetown, ON, to determine if there is an effect of TOD of application on tolpyralate + atrazine efficacy on common annual grass and broadleaf weeds. An application was made at 3-h intervals beginning at 06:00 h with the last application at 24:00 h. There was a slight TOD effect on velvetleaf, pigweed species, and common ragweed control with tolpyralate + atrazine; however, the magnitude of change throughout the day was ≤3% at 2, 4, or 8 wk after application (WAA). There was no effect of TOD of tolpyralate + atrazine on the control of lambsquarters, barnyardgrass, and green foxtail. All weed species were controlled ≥88% at 8 WAA. There was no effect of TOD of tolpyralate + atrazine application on corn yield. Results of this study show no evidence of a TOD effect on weed control efficacy with tolpyralate + atrazine.

中文翻译：

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甲苯磺酸加阿特拉津对杂草控制效果的时间效应

Tolpyralate 是一种新的 4-羟基苯基丙酮酸双加氧酶 (HPPD) 抑制除草剂，用于控制玉米杂草。先前的研究已经报道了甲苯磺酸酯 + 阿特拉津对几种一年生草和阔叶杂草的功效；然而，没有研究评估过根据施用时间 (TOD) 对甲苯吡拉酸 + 阿特拉津的杂草控制情况。在安大略省 Ridgetown 附近的 2 年期间（2018 年、2019 年）进行了 6 次田间试验，以确定 TOD 的施用是否对常见的一年生禾本科杂草和阔叶杂草的甲苯吡拉酸 + 阿特拉津功效有影响。从 06:00 开始，每隔 3 小时进行一次申请，最后一次申请是在 24:00 进行。用甲苯磺酸酯 + 阿特拉津对鹿茸、猪草和普通豚草控制有轻微的 TOD 影响；然而，全天的变化幅度在 2 时≤3%，4 或申请后 8 周 (WAA)。甲苯磺酸+阿特拉津TOD对羔羊草、稗草和狐尾草的防治效果不显着。在 8 WAA 时，所有杂草种类均控制 ≥88%。甲苯磺酸+阿特拉津施用的TOD对玉米产量没有影响。这项研究的结果显示，没有证据表明 TOD 对甲苯吡拉酸 + 阿特拉津的杂草控制效果有影响。