Experiments were conducted to evaluate sharppod morningglory control with postemergence herbicides used in cotton and to determine the influence of diuron on glyphosate efficacy. Glyphosate plus diuron was one of the most efficacious herbicide treatments in the field experiment, providing up to 78% control of 10- to 20-cm stem length sharppod morningglory. In growth-chamber experiments, mixtures of either 420 or 840 g ai/ha diuron plus glyphosate potassium salt at 840 g ae/ha were needed to significantly reduce sharppod morningglory biomass. Compared to published results with other Ipomoea spp. and field bindweed, sharppod morningglory absorbed more and translocated less glyphosate after 72 h. Retention of glyphosate in treated leaves increased when the glyphosate was mixed with 420 g/ha diuron. Mixture with 420 or 840 g/ha diuron reduced the concentration of glyphosate in roots; however, only 2% of glyphosate alone was translocated to the roots. These results indicate that the combination of glyphosate with diuron improves aboveground sharppod morningglory desiccation, but limits glyphosate translocation.
Nomenclature: Diuron; glyphosate; field bindweed, Convolvulus arvensis L.; sharppod morningglory, Ipomoea cordatotriloba Dennstedt IPOTC; cotton, Gossypium hirsutum L