Infestations of Italian ryegrass are difficult to control and decrease marketability of cool-season sod. Tests were conducted at three locations in Virginia in 2002 and 2003 to determine herbicide control options for Italian ryegrass in 90:10 tall fescue:Kentucky bluegrass turfgrass seeded the previous fall. Chlorsulfuron, diclofop, fluazifop plus fenoxaprop, and metsulfuron controlled 5- to 30-tiller Italian ryegrass less than 50% 10 weeks after initial treatment (WAIT). Nicosulfuron at 53 g ai/ha controlled Italian ryegrass 69 to 95% and injured turf no greater than 10% at all locations 10 WAIT. Primisulfuron at 53 g ai/ha controlled Italian ryegrass less than 30% in 2002, and 59 to 63% at two locations in 2003 10 WAIT and injured turf less than 5% at all locations. Results indicate nicosulfuron can be used for Italian ryegrass control in tall fescue or tall fescue and Kentucky bluegrass turf if temporary injury is acceptable.

Nomenclature: Chlorsulfuron; diclofop; fenoxaprop; fluazifop; metsulfuron; nicosulfuron; primisulfuron; Italian ryegrass, Lolium multiflorum Lam. # LOLMU; Kentucky bluegrass, Poa pratensis L. ‘Midnight’ ‘Millenium’; tall fescue, Festuca arundinacea Schreb. ‘Falcon III’, ‘Rebel II’.

Additional index words: Sod production, turfgrass injury, weed control.
Abbreviations: ESF, Enfield Sod Farm, Aylett, VA 2002; TRC, Turfgrass Research Center, Blacksburg, VA 2003; VTF, Virginia Turf Farm, Baskerville, VA 2003; WAIT, weeks after initial treatment.

Citation: Beam, J. B. and S. D. Askew. 2005. Italian ryegrass (Lolium multiflorum) control in newly seeded tall fescue (Festuca arundinacea). Weed Technol. 19(2):156-161.