SULFONYLUREA HERBICIDES FOR SEDGE & KYLLINGA CONTROL. F. H. Yelverton*1, P. C. Bhowmik2, T. W. Gannon1; 1North Carolina State University, Raleigh, NC, 2University of Massachusetts, Amherst, MA (174)


Purple nutsedge (Cyperus rotundus L.) and false-green kyllinga (Kyllinga gracillima Miq.) are common, rapidly spreading perennial weed species in turfgrass environments that prefer above normal soil moisture. Sedge incidence has increased in recent years in turfgrass systems, likely due in part to changes in herbicide programs. Although purple nutsedge is not as widely distributed as other Cyperus species, it has been described as the world’s worst weed because it is a serious competitor with more crops that any other weed in the world. False-green kyllinga is a rhizomatous perennial which is similar to green kyllinga (Kyllinga brevifolia Rottb.) and may be differentiated by seed morphology or flower timing. Sulfosulfuron is a sulfonylurea herbicide developed for postemergent weed control in wheat and select cool- and warm-season turfgrasses. Trifloxysulfuron is another sulfonylurea herbicide currently registered for postemergent weed control in cotton (Gossypium hirsutum L.), sugarcane (Saccharum spp.) and select warm-season turfgrasses. Field trials were conducted to evaluate sulfosulfuron and trifloxysulfuron for postemergent false-green kyllinga and purple nutsedge control. All treatments included NIS (0.25 % v/v) and were applied with a CO2-propelled backpack sprayer.  Sulfosulfuron (66 fb 66 g ai ha-1) and trifloxysulfuron (28 fb 28 g ai ha-1) provided acceptable (> 80%) false-green kyllinga and purple nutsedge control. Application volume did not influence the efficacy of evaluated treatments. These data indicate sulfosulfuron and trifloxysulfuron may offer effective sedge control in turfgrass environments.