Broad spectrum effectiveness of pyroxasulfone + flumioxazin for weed control in pre-emergence of soybean

It is necessary to search for solutions to control weeds, focusing on pre-emergent herbicides. Pyroxasulfone + flumioxazin is believed to be effective in controlling weeds in soybean, as well as other pre-emergent herbicides used in this crop. The aim of this study was to evaluate the effectiveness of the pre-formulated mixture pyroxasulfone + flumioxazin, for application in pre-emergence of soybean. Experiment was conducted in two trials in the 2020-2021 growing season. The treatments consisted of non-treated control, pyroxasulfone + flumioxazin (90 + 60 g ai ha-1), imazethapyr + flumioxazin (100 g ae ha-1 + 50 g ai ha-1), diclosulam (29.4 g ai ha-1), sulfentrazone + diuron (175 + 350 g ai ha-1) and s-metolachlor (1,440 g ai ha-1). Trial 1 was infested with Digitaria insularis (sourgrass), Ipomoea spp., Urochloa plantaginea (alexandergrass), and Amaranthus hybridus (smooth pigweed). Trial 2 was infested with sourgrass, morning glory, other grasses, and other broadleaves. Weed control, soybean injury and yield were evaluated. Pyroxasulfone + flumioxazin stood out, which was the only one among the best in all evaluations, demonstrating its broad spectrum of action. Also highlighted are the other formulated premixes, imazethapyr + flumioxazin and sulfentrazone + diuron. Diclosulam was almost always among the most effective in controlling broadleaves, but with the worst performance in controlling grasses, the opposite was observed for s-metolachlor. Herbicides are effective in controlling weeds, with emphasis on pyroxasulfone + flumioxazin, imazethapyr + flumioxazin and sulfentrazone + diuron, effective in controlling sourgrass, smooth pigweed, morning glory, alexandergrass, among others.