Optimizing weed control using dicamba and glufosinate in eligible crop systems

Abstract A field experiment was conducted in 2019 and 2020 that included six site-years four locations Arkansas to determine the optimal sequence timing of dicamba glufosinate applications when applied alone, sequentially, or combination control Palmer amaranth by size: labeled (<10 cm height) non-labeled (13 25 height). Single dicamba, glufosinate, plus (not labeled) resulted less than 80% control, regardless weed size. The mixture antagonistic for percent mortality. Sequential applications, averaged over all time intervals herbicides, improved percentage 11 17 points a single application, size at application 28 d after final (DAFA). with followed (fb) fb pending size, were optimized 7 d, 14 21 respectively. Because site action (SOA) postemergence herbicide systems increase likelihood development resistant biotypes are not best management practice (BMP) regard; sequential involving both more effective. Furthermore, mattered preference applying first. Dicamba 14-d interval profit-maximizing only treatment 100% <10 cm. For larger sizes, economic analysis revealed performed better no penalty assigned using SOA. This greater yield loss risk soil seed bank comparison timelier smaller Hence, timely two SOAs recommended as BMPs reduce producer risk.