Control of glyphosate-resistant horseweed with Group 4 herbicides in soybean

Abstract Little information is available on the relative efficacy of Group 4 herbicides for glyphosate-resistant (GR) horseweed management in soybean. Five field research experiments were conducted growers’ fields from 2020 to 2021 determine GR control with applied preplant (PP) alone and a mixture. There was minimal soybean injury (≤4%) evaluated. Dicamba, 2,4-D, or halauxifen-methyl PP controlled 92% 96%, 73% 76%, 85% 89%, respectively. The mixtures dicamba + 2,4-D provided 97% 99% horseweed, similar alone. mixture 93% 94% horseweed. Dicamba saflufenacil at 98%. alone, ester, halauxifen-methyl, ester decreased density 97%, 99%, 98%, respectively, 98% reduction saflufenacil. Other herbicide treatments had no effect density. dry biomass by 72%, 100%, 94%. Soybean yield 61% when left uncontrolled. Results show that include can be very effective managing