Creeping bentgrass ( Agrostis stolonifera ) is the most adapted and desirable turfgrass species for golf course putting greens in most temperate climates. However, one of the major challenges that golf course superintendents face with managing newer
Paweł Petelewicz, Paweł M. Orliński, and James H. Baird
Monica L. Elliott, J.A. McInroy, K. Xiong, J.H. Kim, H.D. Skipper, and E.A. Guertal
Golf course putting greens are composed of a turfgrass monoculture. In the southeastern United States, bentgrass ( Agrostis palustris Huds.) and hybrid bermudagrass [ Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] are the dominant
Ty A. McClellan, Roch E. Gaussoin, Robert C. Shearman, Charles S. Wortmann, Martha Mamo, Garald L. Horst, and David B. Marx
turfgrass use, maintenance, and performance. Inadequate or excessive soil nutrient levels can lead to problems in turfgrass health, vigor, and quality ( Beard, 1973 ; Turner and Hummel, 1992 ). Putting greens comprise ≈1.6% of the total golf course area
Nicholas Menchyk, Douglas G. Bielenberg, Samuel Martin, Clint Waltz, Hong Luo, Frank Bethea Jr., and Haibo Liu
Golf course managers in the transition zone of the United States commonly establish and manage creeping bentgrass ( Agrostis stolonifera L.) as putting greens. However, several turfgrass species have been introduced as alternatives to cool
Steven M. Borst, J. Scott McElroy, and Greg K. Breeden
Silvery-thread moss encroachment is an increasing problem on creeping bentgrass putting greens across the United States ( Burnell et al., 2004 ; Danneberger and Taylor, 1996 ; Happ, 1998 ). Silvery-thread moss can be found in many environments
Paweł Petelewicz, Paweł M. Orliński, Marco Schiavon, Manuel Mundo-Ocampo, J. Ole Becker, and James H. Baird
( Costello, 1983 ). Identified initially as Anguina radicicola , Cid Del Prado and Maggenti (1984) renamed the nematode with its current name. An endoparasitic pathogen of annual bluegrass ( Poa annua ), it is damaging primarily to putting greens. It
Monica L. Elliott, Robert B. Hickman, and Mark Hopkins
Type 1 (necrotic) fairy rings in turfgrass result in dead or badly damaged grass. This type of fairy ring is a severe problem on golf course greens as they interfere with the aesthetics and playability of the putting surface. In Florida, Lycoperdon spp., basidiomycetes that produce puffball mushrooms, have been implicated as a common cause of Type 1 fairy rings on hybrid bermudagrass (Cynodon dactylon × C. transvaalensis) putting greens. The fungicide flutolanil has basidiomycetes as the sole fungal target. It is also the only carboxin-related fungicide registered for use on turfgrass. Two experiments were conducted to examine the effect of flutolanil as a curative and preventive treatment for fairy ring caused by Lycoperdon. One experiment, established after the rings were present, determined that flutolanil significantly reduced mushroom production. The second experiment was conducted on a golf course that had experienced Type 1 fairy rings previously. One-half of each of nine putting greens was treated with flutolanil on a preventive basis. The other half of each green served as an untreated control. Type 1 fairy rings, due to Lycoperdon, developed only on the untreated control half of each green. These experiments confirm that flutolanil does have curative and preventive activity against Lycoperdon spp. that cause Type 1 fairy rings.
M.L. Elliott, E.A. Guertal, and H.D. Skipper
The rhizospheres of creeping bentgrass (Agrostis palustris Huds.) and hybrid bermudagrass (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy) putting greens were sampled quarterly for 4 years. Six bacterial groups, including total aerobic bacteria, fluorescent pseudomonads, actinomycetes, Gram-negative bacteria, Gram-positive bacteria, and heat-tolerant bacteria, were enumerated. The putting greens were located in four geographic locations (bentgrass in Alabama and North Carolina; bermudagrass in Florida and South Carolina) and were maintained according to local maintenance practices. Significant effects were observed for sampling date, turfgrass species and location, with most variation due to either turfgrass species or location. Bentgrass roots had significantly greater numbers of fluorescent pseudomonads than bermudagrass roots, while bermudagrass roots had significantly greater numbers of Gram-positive bacteria, actinomycetes and heat-tolerant bacteria. The North Carolina or South Carolina locations always had the greatest number of bacteria in each bacterial group. For most sampling dates in all four locations and both turfgrass species, there was a minimum, per gram dry root, of 107 CFUs enumerated on the total aerobic bacterial medium and a minimum of 105 CFUs enumerated on the actinomycete bacterial medium. Thus, it appears that in the southeastern U.S. there are large numbers of culturable bacteria in putting green rhizospheres that are relatively stable over time and geographic location.
Matthew J. Fagerness, John Isgrigg III, Richard J. Cooper, and Fred H. Yelverton
Questions exist as to whether growth-inhibiting chemicals mimic the effects of reduced mowing heights on putting green ball roll. An experiment was initiated during Spring 1997 to investigate ball roll and visual quality parameters of putting greens maintained at 3.2, 4.0, or 4.8 mm with plant growth regulator (PGR) treatments applied monthly over the course of 1 year. Additional experiments were conducted during Fall 1995 and 1996 and Spring 1996 to investigate diurnal PGR effects on ball roll. All experiments were conducted on pure stands of `Penncross' creeping bentgrass (Agrostis palustris Huds). Treatments included trinexapac-ethyl and paclobutrazol, both inhibitors of gibberellin biosynthesis. In the one-year experiment, mowing height was inversely related to ball roll. However, compromises in turfgrass visual quality and shoot density in `Penncross' turf mowed at 3.2 mm make this a questionable mowing height in areas with severe summer conditions. Ball roll during summer months was reduced by PGRs, suggesting that PGRs have little potential as alternatives to decreasing mowing height for increased ball roll. Paclobutrazol reduced turfgrass quality and shoot density during summer months, suggesting that it be used with caution. Other PGRs, particularly trinexapac-ethyl at 0.05 kg·ha–1 a.i., increased afternoon ball roll by as much as 5% to 10% in diurnal experiments. Use of PGRs on creeping bentgrass putting greens may therefore produce short-lived increases in ball roll with subtle to negative effects on bentgrass growth over more extended periods of time. Chemical names used: 4-(cyclopropyl-α-hydroxymethylene)-3,5-dioxocyclohexane carboxylic acid ethylester (trinexapac-ethyl); (+/–)-(R *,R *)-β-[(4-chloro-phenyl)methyl]-α-(1,1dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
Christian M. Baldwin, Haibo Liu, and Philip J. Brown
Hollow tine cultivation is a routine practice on golf course putting greens, where the tine entry angle normally is 90°. Effects of various tine entry angles impacting putting green surfaces have not been investigated. The hypothesis was that different tine entry angles during cultivation would impact a greater area of the soil profile by enhancing water infiltration rates, reducing localized dry spots, and enhancing turf quality. Therefore, a 2-year field study in 2003 and 2004 was conducted to determine the impact of core cultivation tine entry angle on `Crenshaw' creeping bentgrass (Agrostis stoloniferous var. palustris). Treatments included three angles of hollow tine entry at 50°, 70°, and 90° and an untreated plot without cultivation. Manual cultivators consisted of four 1/4-inch- and 1/2-inch-diameter hollow tines 3 inches in length, spaced 2 inches apart. Treatment applications were in April, May, September, and October. Measurements included visual turfgrass quality (TQ), molarity ethanol droplet test (MED), and water infiltration. No treatment (control, 50°, 70°, 90°) effects in years I and II for TQ were noted. MED scores in May were 23% higher than in August and September. Tines of 1/2-inch diameter reduced soil hydrophobicity (MED) 6% compared to tines of 1/4-inch-diameter tines. Tines of 50°, 70°, and 90° had 129%, 163%, and 211% greater water infiltration than the untreated, respectively.