Effect of Cultivar and Planting Date on Soybean Response to Dicamba

Off-target movement of dicamba has been blamed for damaging millions hectares soybean in the United States since registration herbicide use dicamba-resistant cotton and soybean. Understanding effect a low dose on non-dicamba-resistant across multiple cultivars, growth stages, planting dates could help producers better understand implication current management practices yield loss from fields where are grown. A field experiment was conducted 2019 Fayetteville Stuttgart, Arkansas, to evaluate impact date response dicamba. The hypothesis that injury will differ depending application timing. Additionally, an 2018 assess whether cultivars sensitivity cultivar genetic differences allow differential tolerance In experiment, “Eagle DrewSoy” identified as having enhanced based reduced (47% at R1 26% V3) over both experimental years locations. Soybean height this affected only by after mid-June resulted yields injury. Dicamba exposure July (61% reduction nontreated) more severely when compared dicamba-treated plots other (94% average relative among dates), indicating negative effects increasingly deleterious planted later growing season. Maximum manifestation generally delayed dates, may have metabolized slowly.