Effectiveness of Metribuzin Applied Preemergence for Economical Control of Common Cocklebur in Soybeans

Abstract

The effectiveness of several preemergence and postemergence weed control systems for control of common cocklebur (Xanthium pensylvanicumWallr.) in soybeans [Glycine max(L.) Merr.] was determined in field research over a 3-yr period. Sequential applications of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] at 1.1 kg/ha applied preemergence, and dinoseb (2-sec-butyl-4,6-dinitrophenol) at 1.7 kg/ha, 2,4-DB [4-(2,4-dichlorophenoxy)butyric acid] at 0.2 kg/ha, or bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2,2-dioxide] at 1.1 kg/ha applied postemergence, provided at least 90% control of common cocklebur and increased soybean yields. Use of single herbicide applications was less effective than sequential applications, but metribuzin applied preemergence was more effective in controlling common cocklebur and increasing soybean yields than single applications of any herbicide applied postemergence. Effective control of common cocklebur with sequential herbicide treatments increased soybean seed grades by reducing discounts caused by several grade lowering components including moisture content and foreign material in harvested seed. Use of all herbicide practices increased returns above specified costs, but greatest returns followed use of sequential treatments.