Integrated strategies to improve weed control in beet crop rotations in the Willamette Valley (2013)

Research report to the Oregon Processed Vegetable Commission

Ed Peachey
OSU Dept. of Horticulture

The objective of this research was to determine best use patterns for Upbeet herbicide considering factors of preemergence herbicide and cultivation, and how these affect optimum timing for Upbeet applied with or without Spin-Aid for control of weeds such as nightshade and lambsquarters. At the OSU Vegetable Research Farm in Corvallis, weed control at harvest was influenced primarily by whether Dual Magnum and Nortron were applied PRE. Weed control was a primary determinant of yield. The second most important factor influencing weed control at harvest was cultivation, which on average improved weed control from 70 to 88% when used with PRE herbicide. UpBeet applied at the 4-leaf beet stage controlled weeds better than when applied at the 2-leaf stage (88 vs. 70 % control), but did not significantly improve yield. When Spin-Aid was tankmixed with UpBeet, it also controlled weeds better at the 4-leaf stage than the 2-leaf stage (86 vs. 75% control). Cultivation at 2-leaf provided better weed control than at 4-leaf when PRE herbicides were used. Late cultivation (4-leaf) may have actually disrupted the control provided by the PRE herbicide. The best weed control was with PRE herbicide followed by UpBeet at 2-leaf followed one day later by a 2-leaf cultivation, and this treatment also yielded the most beets. At the on-farm site near St. Louis, all POST treatments improved weed control compared to Ro-Neet alone. Ro-Neet followed by (fb) Dual Magnum + Nortron PRE stunted beet growth by as much as 40% one month after planting but did not affect yield. UpBeet applied at the 2-leaf stage controlled weeds and provided the greatest yield. UpBeet herbicide may fill an important niche in weed control programs in table beets, but successful performance will be tied to when the application is made relative to beet and weed growth stage, and whether it is used in concert with cultivation and Spin-Aid.