Published online by Cambridge University Press: 12 June 2017
Mefluidide {N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]-amino] phenyl] acetamide} was applied postemergence in soybean [Glycine max (L.) Merr.] fields and its effectiveness in controlling johnsongrass [Sorghum halepense (L.) Pers.], hemp sesbania [Sesbania exaltata (Raf.) Cory], and common cocklebur (Xanthium pensylvanicum Wallr.) was evaluated. In plots treated preplanting with trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), mefluidide gave 95% johnsongrass control when it was applied postemergence (over-the-top without surfactant) once at 0.90 kg/ha or twice at 0.44 kg/ha. Directed sprays of mefluidide at 0.22 to 0.67 kg/ha without surfactant were more effective on johnsongrass than similar treatments applied over-the-top. When 0.5% (v/v) nonoxynol [α-(p-nonyl-phenyl)-ω-hydroxypoly (oxyethylene)] surfactant was added, mefluidide at 0.44 or 0.67 kg/ha applied as directed or over-the-top sprays provided 76 to 90% johnsongrass control. Mefluidide at 1.12 kg/ha plus nonoxynol surfactant, applied as a directed spray, was required to provide 81% control of hemp sesbania. Directed sprays containing mixtures of mefluidide at 0.28 kg/ha plus dinoseb (2-sec-butyl-4,6-dinitrophenol) at 2.2 kg/ha, or mefluidide at 0.28 kg/ha plus a 2:1 mixture of naptalam (N-1-naphthylphthalamic acid)/dinoseb at 4.7 L/ha, effectively controlled 40- to 60-cm-tall hemp sesbania. A single, directed spray of mefluidide at 0.56 kg/ha plus nonoxynol provided 92% common cocklebur control, and mixtures of mefluidide at 0.28 kg/ha plus dinoseb at 2.2 kg/ha or naptalam/dinoseb (a 2:1 mixture) at 4.7 L/ha increased control above that provided by either of the herbicides alone.