Purple Nutsedge Control by Bentazon and Perfluidone in Turfgrasses

Abstract

Field and greenhouse experiments were conducted on bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)one 2,2-dioxide] at 2.2 and 4.4 kg/ha and perfluidone {1,1,1-trifluoro-N-[2-methyl-4-(phenylsulfonyl) phenyl] methanesulfonamide} at 4.5 and 9.0 kg/ha for purple nutsedge (Cyperus rotundus L.) control and tolerance of five turfgrasses. A single application of each herbicide was applied to purple nutsedge, but single and repeated applications were applied to turfgrasses. Purple nutsedge control during the initial year of treatment was 98 to 100% when bentazon was applied in late spring, but the control was only 28 to 68% when applied in mid or late summer. Perfluidone controlled 76 to 87% of purple nutsedge when applied in late spring and 95 to 100% when applied in late summer. Bentazon treatments generally did not cause turf injury. In the field, perfluidone treatments injured St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze], zoysia grass (Zoysia japonica × Z. teniuflolia ‘Emerald’), centipedegrass [Erenoehloa ophiuroides (Munro) Hack.], and common bermudagrass [Cynodon dactylon (L.) Pers.]. ‘Tifway’ bermudagrass was generally tolerant to perfluidone treatments. In the greenhouse, perfluidone reduced the root growth of all turfgrasses except centipedegrass when compared with untreated checks.