FENOXAPROP AND AMINOCYCLOPYRACHLOR COMBINATIONS ARE COMPATIBLE FOR POSTEMERGENCE BROAD SPECTRUM WEED CONTROL. S. Hart*, J. Brosnan, and P. McCullough, Rutgers University, New Brunswick, NJ (90)
Fenoxaprop effectively controls crabgrass (Digitaria spp.) in tall fescue (Festuca arundinacea L.) turf but antagonism with growth regulating herbicides reduces potential to apply fenoxaprop in combination with many herbicides registered for broadleaf weed control. Aminocyclopyrachlor is a new broadleaf weed control herbicide that has not been evaluated in combination with fenoxaprop. Field experiments were conducted in Georgia, New Jersey, and Tennessee to investigate tank-mixtures of fenoxaprop with aminocyclopyrachlor for smooth crabgrass and white clover control. Fenoxaprop alone exhibited substantial activity on smooth crabgrass but synergistic effects were detected with fenoxaprop + aminocyclopyrachlor treatments. By 4 and 6 weeks after treatment (WAT), approximately 22 and 44% less fenoxaprop was required to achieve 80% smooth crabgrass control when the herbicide was tank-mixed with aminocyclopyrachlor at 220 and 330 g ai/ha, respectively. Fenoxaprop did not reduce white clover control with aminocyclopyrachlor as 97% control was achieved by 4 WAT for all aminocyclopyrachlor + fenoxaprop treatments. Tall fescue was not injured from any treatment. Results suggest aminocyclopyrachlor enhances fenoxaprop efficacy for smooth crabgrass control in tall fescue.