BUFFALOGRASS SEEDLING TOLERANCE TO POSTEMERGENCE HERBICIDES

In 1992 and 1993, 12 postemergence herbicide treatments were applied t o field-grown buffalograss [Buchloe dactyloides (Nutt.) Engelm.] seedl ings having 1 to 3 leaves and 2 to 4 tillers, respectively. The only h erbicide treatments that did not cause plant injury at 1 or 2 weeks af ter treatment (WAT) or reduce turf coverage 4 or 6 WAT compared to non treated plots (in 1992 or 1993) were (in kg.ha-1) 0.6 dithiopyr, 0.8 q uinclorac, 2.2 NISMA, and 0.8 clorpyralid. Evaluated only in 1993, met sulfuron methyl (0.04 kg.ha-1) also caused no plant injury or reductio n in coverage. Fenoxaprop-ethyl (0.2 kg.ha-1) caused severe plant inju ry and reduced coverage by >95 % at 6 WAT. Dicamba reduced coverage by 11 % at 6 WAT in 1992 but not 1993. The chemicals (in kg.ha-1) triclo pyr (0.6), 2,4-D (0.8), triclopyr (1.1) + 2,4-D (2.8),2,4-D (3.1) + tr iclopyr (0.3) + clorpyralid (0.2), and 2,4-D (2.0) + mecoprop (1.1) dicamba (0.2) caused plant injury at 1 or 2 WAT in 1992 or 1993, but c overage was similar to that of nontreated turf by 6 WAT. Chemical name s used: 3,6-dichloro-2-pyridinecarboxylic acid (clorpyralid); 3,6-dich loro-o-anisic acid (dicamba); (+/-)-2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid (diclofop); 3,5-pyridinedicarbothioic acid, -(2-methylp ropyl)-6-(trifluoromethyl)-S,S-dimethyl ester (dithiopyr); 2-[4-[(6-ch loro-2-benzoxazolyl)oxy]phenoxy] propanoate (fenoxaprop-ethyl); 2-(2,4 -dichlorophenoxy)propionic acid (mecoprop); methyl iazin-2-yl)-amino]c arbonyl]amino]sulfonyl]benzoate (metsulfuron methyl); monosodium salt of methylarsonic acid (MSMA); 3,7-dichloro-8-quinolinecarboxylic acid (quinclorac); [(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid (triclopy r); (2,4-dichlorophenoxy) acetic acid (2,4-D).