Abstract: A field study was conducted in 1992 and 1993 to identify the spray volume and droplet size combinations to optimize control of common cocklebur (Xanthium strumarium) from acifluorfen by maximizing target deposition. In many instances, acifluorfen controlled common cocklebur better using either small (250 µm) or large (450 µm) spray droplets when applied at the lower carrier volumes of either 56 or 112 L/ha. When sprays were applied at 169 L/ha, there was little difference in control between droplet sizes. Deposition of acifluorfen was determined in 1993. Stepwise regression indicated that acifluorfen deposition amount is less important than environmental conditions for common cocklebur control. Relative humidity was the most significant variable for determining common cocklebur control with acifluorfen.
Nomenclature: Acifluorfen, 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid; common cocklebur, Xanthium strumarium L. #3 XANST.
Additional index words: Acifluorfen, deposition, efficacy, XANST.
Abbreviations: VMD, volume median diameter; WAT, weeks after treatment.
