Effect of Herbicide Treatments on Overseeded Putting Green Turf

Putting green turf containing perennial ryegrass (Lolium perenneL. ‘Medalist IV’) overseeded on a bermudagrass [Cynodon dactylon(L.) Pers. ‘Tifway’] was treated with single and sequential herbicide treatments during the spring and transition period from cool to warm season grass. Oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one] at 2.2 or 4.4 kg/ha and butralin [4-(1,1-dimethylethyl)-N-(1-methylpropyl)-2,6-dinitrobenzenamine] at 3.4 or 6.7 kg/ha reduced the quality of putting green turf immediately after treatment in early spring. Turf injury was greater with oxadiazon than with butralin. Two applications of MSMA (monosodium methanearsonate) at 2.2 or 3.4 kg/ha resulted in a lower quality turf with less ryegrass when compared with the untreated check. Methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] at 1.1 kg/ha severely injured ryegrass and resulted in a lower turf quality.