Differential Response of Five Bahiagrass (Paspalum notatum) Cultivars to Metsulfuron1

Bahiagrass is used for roadsides, pastures, and lawns in the southeastern United States mainly because of drought and nematode tolerance. Metsulfuron is a sulfonylurea herbicide, which selectively controls bahiagrass in bermudagrass. Certain cultivars of bahiagrass were observed to be tolerant to recommended rates of metsulfuron. Therefore, research was conducted to investigate the susceptibility of five major bahiagrass cultivars to metsulfuron applied at increasing rates to 42 g ai/ha. Five bahiagrass cultivars were evaluated: ‘Pensacola’, ‘Tifton-9’, ‘Argentine’, ‘Common’, and ‘Paraguayan’. Argentine, Common, and Paraguayan cultivars showed a four- to fivefold increased tolerance to metsulfuron compared with Pensacola. Because of yearly inconsistencies, results for Tifton-9 were inconclusive.Nomenclature: Metsulfuron; Argentine bahiagrass, Paspalum notatum Fluegge var. notatum ‘Argentine’; bermudagrass, Cynodon dactylon (L.) Pers; Common bahiagrass, Paspalum notatum Fluegge var. notatum ‘Common’; Paraguayan bahiagrass, Paspalum notatum Fluegge var. notatum ‘Paraguayan’; Pensacola bahiagrass, Paspalum notatum Fluegge var. saurae Parodi ‘Pensacola’; Tifton-9 bahiagrass, Paspalum notatum Fluegge var. saurae Parodi ‘Tifton-9’.Abbreviations: GR50, metsulfuron rate required to reduce regrowth to 50% of untreated; OM, organic matter; WAT, weeks after treatment.