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Rattail fescue is a problematic weed for small grain producers in the Pacific Northwest when no-till production practices are used. Pyroxsulam and pyroxasulfone are two herbicides not previously evaluated for control of rattail fescue. Pyroxasulfone provided levels of control (> 74%) similar to flufenacet. Pyroxsulam did not consistently control (21 to 71%) rattail fescue. Rattail fescue biomass was reduced by pyroxasulfone and flufenacet compared to the nontreated control. Effective consistent rattail fescue control was only achieved where PRE herbicides were used. When managing rattail fescue, PRE herbicides pyroxasulfone and flufenacet plus metribuzin are essential components of an integrated management strategy.
Nomenclature: Flufenacet; pyroxasulfone; pyroxsulam; rattail fescue, Vulpia myuros (L.) K.C. Gmel., VLPMY; wheat, Triticum aestivum L.
Key words: Direct seed, herbicide efficacy, no-till.
Vulpia myuros es una maleza problemática para los productores de granos en el Pac'ýfico Noroeste de Estados Unidos cuando se usan prácticas de produccíon de labranza cero. Pyroxsulam y pyroxasulfone son dos herbicidas que no han sido evaluados previamente para el control de V. myuros. Pyroxasulfone brindó niveles de control (.74%) similares a flufenacet. Pyroxsulam no controló V. myuros consistentemente (21 a 71%). La biomasa de V. myuros fue reducida por pyroxasulfone y flufenacet al compararse con el testigo sin tratamiento. Un control efectivo y consistente de V. myuros se alcanzó solamente donde se usó herbicidas PRE. Al manejar V. myuros, los herbicidas PRE pyroxasulfone y flufenacet más metribuzin son componentes esenciales para una estrategia de manejo integrada.
Rattail fescue is an introduced winter annual grass native to Eurasia (Jemmett et al. 2008) with a life cycle similar to downy brome (Bromus tectorum L.) and jointed goatgrass (Aegilops cylindrica Host) (Ball et al. 2007). Rattail fescue emergence in disturbed soils is poor and it is intolerant of tillage (Ball et al. 2008); however, rattail fescue is well adapted to low-disturbance cropping systems. Rattail fescue forms thick competitive ''tufts'' in winter wheat that remain after the plant has completed its life cycle (Jemmett et al. 2008). Tufts continue to accumulate in subsequent years, eventually forming residual mats that can interfere with crop establishment and planter operations. In addition to rattail fescue forming a physical barrier to crop establishment, Kato-Noguchi et al. (2010) identified 3-hydroxy-bionone and 3-oxo-a-ionol as allelopathic compounds contained in...