Field surveys were conducted across the Blacklands region of Texas during 2016 and 2017 to document the distribution of herbicide-resistant Lolium spp. infesting winter wheat production fields in the region. A total of 68 populations (64 Italian ryegrass, four perennial ryegrass) were evaluated in a greenhouse for sensitivity to herbicides of three different modes of action: an acetolactate synthase (ALS) inhibitor (mesosulfuron-methyl), two acetyl-coenzyme-A carboxylase (ACCase) inhibitors (diclofop-methyl and pinoxaden), and a 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibitor (glyphosate). Herbicides were applied at twice the label-recommended rates for mesosulfuron-methyl (29 g ai ha−1), diclofop-methyl (750 g ai ha−1), and pinoxaden (118 g ai ha−1); and at the recommended rate for glyphosate (868 g ae ha−1). The herbicide screenings were followed by dose-response assays of the most-resistant ryegrass population for each herbicide at eight rates (0.5, 1, 2, 4, 8, 16, 32, and 64×), compared with a susceptible population at six rates (0.0625, 0.125, 0.25, 0.5, 1, and 2×). The initial screening and dose-response experiments were conducted in a completely randomized design with three replications and two experimental runs. Survivors (<80% injury) were characterized as highly resistant (0% to 20% injury) or moderately resistant (21% to 79%). Results showed that 97%, 92%, 39%, and 3% of the Italian ryegrass populations had survivors to diclofop-methyl, mesosulfuron-methyl, pinoxaden, and glyphosate treatments, respectively. Of the four perennial ryegrass populations, three were resistant to diclofop-methyl and mesosulfuron-methyl, and one was resistant to pinoxaden as well. Perennial ryegrass populations did not exhibit any resistance to glyphosate. Dose-response assays revealed 37-, 196-, and 23-fold resistance in Italian ryegrass to mesosulfuron-methyl, diclofop-methyl, and pinoxaden, respectively, compared with a susceptible standard. One Italian ryegrass population exhibited three-way multiple resistance to ACCase-, ALS-, and EPSPS-inhibitors. The proliferation of multiple herbicide–resistant ryegrass is a challenge to sustainable wheat production in Texas Blacklands and warrants diversified management strategies.

中文翻译：

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耐多种除草剂的黑麦草属。在德克萨斯州布莱克兰的小麦生产中很普遍

2016 年和 2017 年在德克萨斯州布莱克兰地区进行了实地调查，以记录抗除草剂的分布情况黑麦草spp. 侵染该地区的冬小麦生产田。在温室中评估了总共 68 个种群（64 个意大利黑麦草，4 个多年生黑麦草）对三种不同作用模式的除草剂的敏感性：乙酰乳酸合酶 (ALS) 抑制剂（甲磺隆）、两种乙酰辅酶 A 羧化酶(ACCase) 抑制剂（双氯氟草酸和匹诺沙登）和 5-烯醇丙酮酰莽草酸-3-磷酸合酶 (EPSPS) 抑制剂（草甘膦）。除草剂的施用量是甲基磺隆标签推荐用量的两倍（29 g ai ha-1), 甲基双氯氟草醚 (750 g ai ha-1) 和 pinoxaden (118 g ai ha-1); 并以草甘膦的推荐用量（868 g ae ha-1）。除草剂筛选之后，以八种比率（0.5、1、2、4、8、16、32 和 64 倍）对每种除草剂抗性最强的黑麦草种群进行剂量反应分析，而易感种群为 6 倍率（0.0625、0.125、0.25、0.5、1 和 2×）。初始筛选和剂量反应实验以完全随机设计进行，具有三个重复和两个实验运行。幸存者（<80% 的伤害）被表征为高度抵抗（0% 至 20% 的伤害）或中等抵抗（21% 至 79%）。结果显示，意大利黑麦草种群中分别有 97%、92%、39% 和 3% 的双氯氟草胺、甲磺隆、匹诺沙定和草甘膦治疗存活。在四个多年生黑麦草种群中，三个对双氯氟草胺和甲磺隆具有抗性，一种对匹诺沙丁也有抗药性。多年生黑麦草种群对草甘膦没有表现出任何抗性。剂量反应测定显示，与易感标准相比，意大利黑麦草对甲基磺隆、双氯氟草胺和匹诺沙登的耐药性分别为 37 倍、196 倍和 23 倍。一个意大利黑麦草种群对 ACCase-、ALS-和 EPSPS-抑制剂表现出三向多重抗性。多种抗除草剂黑麦草的扩散对德克萨斯州黑地的可持续小麦生产构成挑战，需要采取多样化的管理策略。与易感标准相比。一个意大利黑麦草种群对 ACCase-、ALS-和 EPSPS-抑制剂表现出三向多重抗性。多种抗除草剂黑麦草的扩散对德克萨斯州黑地的可持续小麦生产构成挑战，需要采取多样化的管理策略。与易感标准相比。一个意大利黑麦草种群对 ACCase-、ALS-和 EPSPS-抑制剂表现出三向多重抗性。多种抗除草剂黑麦草的扩散对德克萨斯州黑地的可持续小麦生产构成挑战，需要采取多样化的管理策略。