THE USE OF TOPRAMEZONE AND TRICLOPYR FOR THE MANAGEMENT OF PERENNIAL GRASS INFESTATIONS IN COOL SEASON TURFGRASS. Joseph Zawierucha*1, Larry Newsom2, Clete Youmans2; 1BASF Corp, Research Triangle Park, NC, 2BASF Corporation, Research Triangle Park, NC (31)


Topramezone is under development by BASF for weed control in cool season turfgrasses. Topramezone is a HPPD inhibiting herbicide that controls weeds by inhibiting carotenoid biosynthesis. Topramezone provides broad spectrum control of both broadleaf and grass weeds. Extensive field testing has shown that major cool season turfgrass species exhibit excellent tolerance including: Kentucky bluegrass, fine and tall fescue, and perennial ryegrass. Tolerance levels in most warm season turfgrass species has been shown to be poor with the exception of centipedegrass, which exhibits a high level of tolerance. Field studies conducted in cool season turfgrass with topramezone have demonstrated effective control of key weed species such as white clover, Veronica spp, crabgrass and goosegrass. Additional research has demonstrated that topramezone also offers selective control of key perennial grasses such as bermudagrass when mixed with triclopyr. Effective control of perennial grasses was shown to require a multiple application approach for best results. Control of bermudagrass with topramezone plus triclopyr applied in sequential programs provided superior control to that observed with either herbicide used alone. In addition, the visual bleaching effect of topramezone on bermudagrass was substantially reduced when applied in mixtures with triclopyr. The mixture’s aesthetic benefit of reduced bleaching combined with the enhanced control of weedy bermudagrass should be a valuable tool for cool-season turfgrass managers.