Imazethapyr plus Residual Herbicide Programs for Imidazolinone-Resistant Rice

Field studies were conducted in 2008 and 2009 near Crowley, LA to evaluate the addition of a herbicide with soil-residual activity in mixture with imazethapyr applied very early POST followed by an application of imazethapyr or imazamox 2 wk after the initial application. Weeds evaluated included red rice, barnyardgrass, and alligatorweed. Weed control with treatments including a herbicide with soil-residual activity was equivalent to or higher than imazethapyr applied alone followed by imazethapyr or imazamox. Yield and economical returns were maximized with quinclorac or penoxsulam mixed with imazethapyr followed by imazethapyr or imazamox. The addition of quinclorac or penoxsulam proved to be beneficial in a total weed management program.