Thomas Reed and Patrick E. McCullough, University of Georgia - Griffin, Griffin, GA
Field experiments were conducted to investigate flumioxazin efficacy in combination with postemergence herbicides for annual bluegrass (Poa annua) control in dormant bermudagrass (Cynodon dactylon) and preemergence control of crabgrass (Digitaria spp.). Flumioxazin works best for early postemergence annual bluegrass control, but efficacy may be enhanced in combination with other herbicides on mature annual bluegrass and provide greater residual crabgrass control. Applications were made in February of 2012 and 2013 during a time of typically limited flumioxazin efficacy. Flumioxazin was evaluated at 0.42 kg ai ha-1. Flazasulfuron, glufosinate, glyphosate, mesotrione, pronamide, and simazine were evaluated alone or with flumioxazin. All applications that included flumioxazin provided excellent (>90%) control of crabgrass six months after treatment in 2012, where as no application without flumioxazin provided >58% control. Treatments that included flumioxazin provided greater than or equal control of annual bluegrass than with corresponding herbicide alone and were able to provide 50% control faster than with postemergence herbicide alone.