Weed Management Programs with Pyroxasulfone in Field Corn (Zea mays)

Field experiments were conducted in Louisiana and Mississippi from 2011 through 2013 to evaluate crop injury, weed control, and yield in field corn following pyroxasulfone applied PRE and POST. Pyroxasulfone PRE or POST did not injure corn at any evaluation. Barnyardgrass control was not improved with the addition of any POST treatment to pyroxasulfone alone or atrazine plus pyroxasulfone PRE; however, all POST treatments increased barnyardgrass control to at least 95% at all evaluations following atrazine PRE. All treatments that contained a PRE followed by POST application controlled browntop millet ≥90% at all evaluations. All POST treatments increased ivyleaf morningglory control to ≥92% following atrazine or pyroxasulfone alone PRE. However, control with atrazine plus pyroxasulfone PRE was similar or greater 28 d after POST than all treatments that received a POST application. In the absence of a POST treatment, pyroxasulfone or atrazine plus pyroxasulfone PRE controlled Palmer amaranth 93 to 96% at all evaluations, but atrazine alone PRE provided 84, 82, and 66% control 7, 14, and 28 d after POST, respectively. All programs that contained a PRE followed by POST herbicide treatment controlled Palmer amaranth >90% at all evaluations. Corn yield following all treatments except atrazine alone PRE and the nontreated were similar and ranged from 10990 to 12330 kg ha⁻¹. This research demonstrated that pyroxasulfone can be a valuable tool for weed management in a corn weed management program. Nomenclature: Atrazine; glyphosate; pyroxasulfone; barnyardgrass, Echinochloa crus-galli (L.) Beauv. ECHCG; browntop millet, Urochloa ramosa (L.) Nguyen PANRA; ivyleaf morningglory, Ipomoea hederacea Jacq. IPOHE; Palmer amaranth, Amaranthus palmeri S. Wats. AMAPA; corn, Zea mays L.