Report to the Oregon Processed Vegetable Commission
Ed Peachey, Duongporn Sawanagal, Garvin Crabtree, and Ray William
OSU Dept. of Horticulture
In 1994 we focused on three aspects of vegetation management in sweet corn: herbicide alternatives to atrazine for atrazine tolerant weeds; propane flaming for in-row weed control; and planter efficiency in cover crop residue, no-till systems. Acetochlor effectively controlled tolerant pigweed plus nightshade and barnyard grass for both PPI and PRE applications; including fair control of proso millet at one site. Slight corn injury was noted at higher rates. Acetochlor plus dimethenamid improved weed control slightly, but was no better than acetochlor plus atrazine. Acetochlor plus halosulfuron controlled weeds with low corn injury. Dimethenamid controlled atrazine tolerant pigweed best when applied PPI, but corn injury was moderate. Dimethenamid plus atrazine improved control of tolerant pigweed compared to either herbicide alone (PRE), but had no advantage if dimethenamid was applied PPI with PRE atrazine. Dimethenamid plus atrazine controlled tolerant pigweed better than metolachlor plus atrazine. Halosulfuron and nicosulfuron severely injured corn except in the early planting. Corn injury was severe with a combination of flumetsalam and metolachlor (Broadstrike). Propane flaming controlled in-row weeds in sweet corn with rates ranging from 6.1 to 12.9 gal/acre. Weed emergence was greatly reduced by eliminating spring tillage in a killed cover crop system, and the cross-slot planter effectively planted through cover crop residues of up to 1.5 tons with no detrimental effect on corn growth.