Western ragweed (Ambrosia psilostachya) is an invasive species in spring-sown crops that can also cause allergic rhinitis and asthma due to its allergenic pollen. In order to evaluate the chemical and mechanical control of western ragweed, two separate experiments were conducted in 2019 and 2020. Chemical treatments included non-treated plots, the combination of glyphosate and 2,4-D, glyphosate + ammonium sulfate, bentazon, imazethapyr + surfactant, picloram, 2,4-D, and mechanical treatments included: once mowing at 3–4 leaf stage, once mowing before male flowers' emergence, once mowing early female flowering stage, two mowings at 3–4 leaf stage, two mowings before male flowers' emergence. Results of these studies indicated that in both years, picloram at 0.96 kg ai ha⁻¹ and the combination of 2,4-D and glyphosate at 1.23 + 0.72 kg ai ha⁻¹ provided more than 90% control of western ragweed and reduced plant height, dry weight, and density. The application of imazethapyr and bentazon, respectively, at the rates of 0.1 and 0.96 kg ai ha⁻¹ did not cause visual damage. The mowing shortly before flowering was the most effective mechanical treatment for western ragweed control. In order to the efficient management of the western ragweed, we suggest that the mowing treatments if appropriately timed and application of glyphosate plus 2, 4-D at 1.23 + 0.72 kg ai ha⁻¹, and picloram at 0.96 kg ai ha⁻¹ can prevent western ragweed from spreading by suppressing growth and reducing seed production.

中文翻译：

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入侵性多年生西方豚草 (Ambrosia psilostachya) 对化学和机械控制的反应

西方豚草 ( Ambrosia psilostachya ) 是春季播种作物的入侵物种，由于其花粉过敏，也会引起过敏性鼻炎和哮喘。为了评估西部豚草的化学和机械控制，分别在 2019 年和 2020 年进行了两次试验。化学处理包括未处理的地块、草甘膦和 2,4-D 的组合、草甘膦 + 硫酸铵、苯达松、咪草烟+ 表面活性剂、毒莠定、2,4-D 和机械处理包括：在 3-4 叶期割一次，在雄花出现前割一次，在雌花早期割一次，在 3-4 叶期割两次，两次在雄花出现之前修剪。这些研究的结果表明，在这两年中，毒草胺的剂量为 0.96 kg ai ha ^{−11.23 + 0.72 kg ai ha -1}的 2,4-D 和草甘膦的组合提供了超过 90% 的西部豚草控制，并降低了植物高度、干重和密度。分别以 0.1 和 0.96 kg ai ha ^-1的剂量施用咪草烟和苯达松不会造成视觉损伤。在开花前不久进行割草是控制西方豚草最有效的机械处理方法。为了有效管理西部豚草，我们建议，如果适当定时进行割草处理，施用草甘膦加 2、4-D 1.23 + 0.72 kg ai ha ⁻¹和毒草胺 0.96 kg ai ha ⁻¹可以通过抑制生长和减少种子产量来防止西部豚草的传播。