Timing of Oxadiazon and Quinclorac Application on Newly Sprigged Turfgrass Species

Abstract

Tolerance of sprigged ‘Tifsport’ and ‘Tifdwarf’ bermudagrass, ‘Meyer’ zoysiagrass, and ‘Salam’ seashore paspalum to oxadiazon (2,240 g/ha) or quinclorac (840 g/ha) applied 1 wk before sprigging (WBS), at sprigging (AS), 2 wk after sprigging (WAS), and 4 WAS was investigated in the field. Weed control was also evaluated. For both herbicides only the AS application timing injured the turfgrass greater than 22%, and injury for the other application timings ranged from 9 to 19% 5 WAS. When evaluated 8 WAS turfgrass injury following the AS application timing remained at 19%, and injury for all other timings was 8% or less. Eight WAS the 1 WBS, AS, 2 WAS, and 4 WAS application timings achieved 89, 79, 94, and 99% plot coverage, respectively, when averaged over all turfgrass species/cultivars and herbicides. By 13 WAS, all species/cultivars achieved at least 90% plot coverage. Presprigging applications of oxadiazon provided 98 to 100% goosegrass and old world diamond-flower control. Quinclorac applied AS provided greater than 70% control of these weeds. Results indicate that oxadiazon and quinclorac applied AS will cause unacceptable turfgrass injury. If goosegrass and/or old world diamond-flower are problematic, oxadiazon is a feasible choice for control of these weeds, but quinclorac is not.