PURPLE NUTSEDGE (CYPERUS-ROTUNDUS) CONTROL IN REDUCED-TILLAGE COTTON (GOSSYPIUM-HIRSUTUM L) WITH LOW-VOLUME TECHNOLOGY

Field experiments conducted over three years at Stoneville, MS evaluat ed invert emulsion and oil diluents on the efficiacy of glyphosate and MSMA on purple nutsedge. The herbicides were applied at 0.6 and 1.1 k g ai/ha in an invert emulsion (oil-in-water) and a paraffinic oil at 1 9 L/ha (low-volume) and in water with a non-ionic surfactant (0.25% v/ v) at 187 L/ha (high-volume). Purple nutsedge control with both herbic ides was greater with the low-volume, invert emulsion and oil diluent applications than with high-volume, water diluent applications. Glypho sate and MSMA at 1.1 kg/ha in the oil diluent controlled purple nutsed ge at least 88% when compared with the invert emulsion (greater-than-o r-equal-to 75 and greater-than-or-equal-to 76%, respectively) and wate r (greater-than-or-equal-to 42 and greater-than-or-equal-to 44%, respe ctively) diluents. Cotton injury and seed cotton yields were unaffecte d by any treatment with MSMA but glyphosate with each diluent caused u nacceptable cotton injury and seed cotton yield reduction.