Response of Oat and Broadleaf Weeds to Postemergence Herbicides

Abstract

Spring seeded oat (Avena sativa L.) is a multi‐use crop in the north‐central Great Plains states. However, little efficacy and crop safety data are available on postemergence broadleaf herbicides labeled for use in oat. The objectives of this research were to evaluate broadleaf weed control and potential for crop injury using postemergence herbicides labeled for use in oat. Field experiments were conducted in Minnesota in 2007 and 2008. Pyrasulfotole + bromoxynil was the only herbicide that resulted in oat injury (P = 0.01). All treatments resulted in: excellent visual control of velvetleaf (99%); excellent to good control of redroot pigweed (> 82%), except MCPA amine (58%); excellent to good control of common lambsquarter (> 89%); excellent to good control of wild mustard (> 82%), except dicamba (75%); and excellent to good control of wild buckwheat (> 80%), except MCPA amine; and fluroxypyr + 2,4‐D which resulted in poor control (< 79%). When averaged across locations and years, florasulam + MCPA was the only treatment that resulted in a greater net economic return (NET) compared to the control (P < 0.01). This study provides farmers and consultants with ‘Kame’ oat safety, weed efficacy, and net economic return for twelve commonly used postemergent broadleaf herbicides or mixtures labeled for oat.