| Abstract: | Agrostis stolonifera Huds cv.‘Penncross’ and cv.‘Cohansey’(bentgrass) were maintained as a golf-course putting green. Five herbicides were evaluated at normal (1 x) and three times normal (3 x) rates for Digitaria sanguinalis (L.) Scop (Crabgrass) control and influence on root development of sod. The herbicides were applied once (April), twice (April and August) and three times (April, June and August) annually. After application of 3 × rates, benfluralin (N-butyl-N-ethyl-2,6, dinitro-4-triflouromethylaniline) and chlorthal-dimethyl (2,3,5,6-tetrachloroterephthalic acid dimethyl ester) caused injury on both A. stolonifera cultivars. Shoot injury remained with repeated benfluralin treatments; however, injury was no longer apparent after the first application of chlorthal-dimethyl. Terbucarb (2,6-di-t-butyl-p-tolyl N-methylcarbamate) completely killed both cultivars during the second year of the study. Bensulide (N-[2-(0,0-di-isopropyldithiophosphoryl)ethyl]benzene sulphonamide) and siduron (N-(2-methylcyclohexyl)-N-phenylurea) did not influence shoot growth of either A. stolonifera cultivars. Chlorthaldimethyl, bensulide and siduron allowed excelent sod rooting in both cultivars. The 3 × rate of the three herbicides did affect rooting of ‘Cohansey’ cultivar during the second year of the study, as did the 1 × rate of benfluralin. The benfluralin injury did not persist from one treatment time to the next, even at 3 × rates. Terbucarb restricted root growth for the entire year. Bensulide and siduron provided acceptable D. sanguinalis control and acceptable A. stolonifera tolerance under golf-course green management and re-establishment with turf. |
