Bermudagrass Golf Research Articles

A New Method to Measure Bermudagrass (Cynodon spp.) Golf Course Putting Green Ball Roll Uniformity

Abstract The golf industry has a $170 billion economic impact in the United States, and a vital aspect of the sport is golf course putting green performance. The goal of putting green management is to provide a surface on which a golf ball is rolled uniformly while maintaining acceptable yearlong turfgrass quality. Several devices have been developed to quantify golf ball roll dynamics on putting greens; however, there are limited methods to measure putting green ball roll uniformity. The objective of this research was to assess putting green ball roll uniformity by measuring the dispersion of golf balls released from a modified Perfect Putter device. The Perfect Putter is a lightweight and portable ramped device that was modified to include a fixed hinge to minimize human error associated with golf ball release and a wider base for increased stability. Our method for quantifying ball roll uniformity was as follows: 20 golf balls were released from the device and marked individually. Dispersion length was quantified by measuring the maximum linear distance between two marks parallel to the roll line, whereas dispersion width was quantified by measuring the maximum linear distance between two marks perpendicular to the roll line. These two values were multiplied together to calculate the area of golf ball dispersion. This method measured a range of dispersion areas among geographic locations, turfgrass cultivars, and turfgrass canopy heights. This rapid test of putting surface ball roll uniformity has potential to aid bermudagrass turfgrass managers in maximizing putting green playability.

Soil carbon sequestration in bermudagrass golf course fairways in Lubbock, Texas

AbstractTurfgrasses benefit the environment through conversion of CO2 into stable C stored in soils. Limited research on the sequestration potential of bermudagrass (Cynodon spp.) has been conducted in semiarid climates. The objective of this study was to evaluate soil physiochemical properties of golf courses in Lubbock, TX, to determine C sequestration potential and longevity. Soil was obtained from fairways of five golf courses ranging in age from 13 to 93 yr. Shallow (0–7.5 cm) and deeper (7.5–15 cm) soil depths were tested for soil pH, electrical conductivity, soil organic matter, soil organic C (SOC), inorganic C, total N, inorganic N, and texture. After ANOVA and mean separation, principal component analysis (PCA) was used to group golf courses by soil depth or age. Soil organic matter and SOC decreased with depth, but the rate of SOC accumulation (0.22 Mg C ha−1 yr−1) was lower when compared with previous studies. Maximal C (35.1 and 23.7 Mg C ha−1 in the upper and lower depths) was consistent with previous studies, indicating that C accumulated for a longer period of time. The PCA explained 52.7% of variability in soil physiochemical properties on two axes, but PCA more effectively differentiated soil sampling depth than golf course age. High variability in data among fairways at a single golf course likely resulted in limited grouping capabilities. Including a broader regional representation of golf courses or sampling golf courses between 40 and 70 yr to quantify soils near maximal accumulation would strengthen future studies.

Effects of Cultivation Practices and Products on Bermudagrass Fairways in a Semiarid Region

High evapotranspirational demand combined with poor quality irrigation water increases salinity concerns in semiarid regions. Accumulated salts in the root zone may negatively affect bermudagrass (Cynodon spp.) growth and quality. The objective of this study was to examine the effectiveness of cultivation practices combined with products to enhance fairway conditions without applying leaching water levels. Two golf courses in Lubbock, TX, were selected for this research. Cultivation practices, including noncultivated control, core aerification, and slicing, were conducted in mid‐June of 2015 and 2016. Nine products recommended to enhance water movement or to disassociate sodium were applied within each cultivation treatment at label rates. Soil pH and electrical conductivity (EC) were determined from samples obtained in June, August, and October each year. Volumetric water content, visual turf quality, digital image analysis, normalized difference vegetation index, and ratio vegetation index were assessed from June to October in 2015 and 2016. Soil EC fluctuated with rainfall events. However, no treatment reduced soil EC. Gypsum‐based products increased soil EC but reduced pH at the conclusion of the research. Core aerification reduced aboveground parameters at Golf Course A because aerified holes remained visible throughout summer, whereas slicing and core aerification improved turf quality and ratio vegetation index at Golf Course B. These results emphasize the need to test irrigation water for the salinity hazard before implementing management strategies and the importance of leaching by rainfall or additional irrigation. Lastly, high surface disruption cultivation practices may inhibit bermudagrass recovery on higher clay content soils.Core Ideas Rainfall and high ET fluctuated soil EC of bermudagrass golf fairways. Gypsum products increased soil EC and reduced soil pH after 2 yr of applications. Bermudagrass recovery from core aerification was slowed with higher clay content. Cultivation practices improved parameters on high sand content soil after recovery.

Postemergence Tropical Signalgrass (Urochloa subquadripara) Control with Nonorganic Arsenical Herbicides

Tropical signalgrass (TSG) has become a serious weed problem in tropical and subtropical regions such as Florida in recent years in association with the ban of organic arsenical herbicide use in turf. The purpose of this research was to identify alternative POST herbicides that control TSG. Two field experiments were conducted in bermudagrass golf course fairways in south and central Florida in 2014 and 2015. Several nonorganic arsenical herbicide treatments controlled TSG. In the first experiment, treatments containing amicarbazone alone and in combination with other herbicides provided > 97% TSG control 12 wk after initial treatment (WAIT) in 2014 and 2015. These included a single application of amicarbazone at 0.49 kg ai ha−1, or sequential applications of amicarbazone at 0.25 kg ha−1in combination with foramsulfuron at 0.04 kg ai ha−1, sulfentrazone + imazethapyr at 0.25 kg ai ha−1, thiencarbazone + foramsulfuron + halosulfuron at 0.14 kg ai ha−1, and thiencarbazone + iodosulfuron + dicamba at 0.18 kg ai/ae ha−1. In the second experiment, sequential applications of thiencarbazone + foramsulfuron + halosulfuron at 0.14 kg ha−1in combination with either quinclorac at 0.84 kg ai ha−1or metribuzin at 0.28 kg ai ha−1provided ≥ 85% TSG control 12 WAIT in both years.

Control of American Burnweed (Erechtites hieraciifolia) in Bermudagrass Turf

American burnweed is an early successional summer annual species in the Asteraceae. This weed is a poor competitor; however, it rapidly colonizes disturbed and low-maintenance areas, especially following an environmental disturbance. Recently, turfgrass managers have made adjustments to maintenance practices to satisfy budget requirements and address environmental concerns. This has resulted in reduced mowing frequency in some golf course rough and out-of-play turf areas, and has allowed establishment of broadleaf weed species such as American burnweed which would otherwise be controlled by frequent mowing. The purpose of this study was to evaluate PRE and POST herbicide treatments for American burnweed control in an unmown bermudagrass golf course rough. Single PRE applications of simazine at 2.24 kg ai ha−1and indaziflam at 0.06 kg ai ha−1provided > 80% American burnweed control 24 wk after treatment (WAT) in 2012 and 2013. Sequential combination applications of liquid formulations of dimethenamid-p + pendimethalin (2.24 + 1.68 kg ai ha−1) provided 95% American burnweed control 24 wk after initial treatment in 2012 and 2013. Other PRE treatments did not provide consistent control of American burnweed across rating dates and years. Regardless of year, four POST treatments provided ≥ 87% control at 8 and 16 WAT. These included thiencarbazone + foramsulfuron + halosulfuron (0.02 + 0.044 + 0.07 kg ai ha−1), thiencarbazone + iodosulfuron + dicamba (0.02 + 0.15 + 0.005 kg ai ha−1), triclopyr + clopyralid (0.88 + 0.32 kg ai ha−1), and sulfentrazone + metsulfuron (0.4 + 0.04 kg ai ha−1). Several PRE and POST American burnweed control solutions exist for low maintenance bermudagrass areas. Future research should continue to screen other herbicides for control efficacy and focus on application timing to balance season-long control with minimal chemical inputs.

Bermudagrass and Zoysiagrass Cultivar Selection: Part 2, Divot Recovery

Bermudagrass and Zoysiagrass Cultivar Selection: Part 2, Divot Recovery

Goosegrass and Bermudagrass Competition under Compaction

Goosegrass (Eleusine indica L.) is a serious weed in trafficked areas of bermudagrass (Cynodon spp.) golf and sports turf. The objective of this study was to evaluate soil compaction and canopy cover as determinants of goosegrass competition in bermudagrass turf in sand soil. Goosegrass cover, plant density, and soil penetration resistance (SPR) were measured in traffic and no‐traffic plots in bermudagrass golf course tees and sports field foul areas. Goosegrass plant density and cover were larger in traffic plots compared with no‐traffic plots. Soil penetration resistance increased only at 5.0 cm depth due to traffic, while other soil properties including bulk density measured in golf course tees showed no effect from traffic. Two experiments measured the effect of controlled soil compaction on root and shoot dry weight of goosegrass and bermudagrass in containers. The first experiment evaluated effects of three soil compaction levels (1.14, 1.24, 1.33 g cm−3 bulk density) on goosegrass and bermudagrass grown separately. The second experiment evaluated effects on the two species grown together in competition, from two soil compaction levels (1.07 and 1.26 g cm−3 bulk density), two N application rates (48 and 96 kg ha−1 mo−1), and two mowing heights (1.3 and 2.5 cm). The second experiment also evaluated goosegrass seedling emergence and tiller numbers. When species were grown separately, bermudagrass root and shoot dry weight showed no effect from soil compaction, but goosegrass root weight was reduced. When species were grown together, bermudagrass root weight was reduced by compaction, but goosegrass was not affected. Goosegrass seedling emergence was reduced 58% by high mowing height, which paralleled an increase in bermudagrass canopy cover based on shoot dry weight. Canopy cover, not compaction, more readily explained the competition and infestation of goosegrass in trafficked areas in sand soil.

Trinexapac‐Ethyl Application Regimens Influence Growth, Quality, and Performance of Bermuda Grass and Creeping Bentgrass Putting Greens

Dwarf bermudagrass (Cynodon dactylon × C. transvaalensis Burtt‐Davy) and creeping bentgrass (Agrostis stolonifera L.) are planted for golf greens in the U.S. transition zone, but management regimes, such as the use of a plant growth regulator (PGR), often vary for long‐term culture of the two species. The objective of this experiment was to investigate application regimens of the PGR trinexapac‐ethyl (TE), on growth, quality, and performance of creeping bentgrass and bermudagrass putting greens in Clemson, SC. ‘L‐93’ creeping bentgrass and ‘TifEagle’ bermudagrass putting greens, established in summer 2002 and mowed at 3.2 mm, received TE over 12 wk in three regimens: 0.017 kg ha−1 wk−1, 0.033 kg ha−1 2 wk−1 (biweekly), or 0.05 kg ha−1 3 wk−1 (triweekly) from May to August 2003 and 2004. Creeping bentgrass was not discolored from TE, but unacceptable bermudagrass discoloration (>20%) occurred on one, two, and six dates for weekly, biweekly, and triweekly regimens, respectively. All TE regimens reduced bermudagrass clippings approximately 50% from nontreated bermudagrass across all dates, while creeping bentgrass clipping reductions, approximately 20 to 35% from nontreated grass, were inconsistent. The root masses of both species treated with TE regimens were similar to nontreated turf. Bermudagrass aerification recovery was reduced on two, two, and four dates after weekly, biweekly, and triweekly TE regimens, respectively. All TE regimens increased morning and evening bermudagrass golf ball roll distance approximately 25 cm from morning distances of nontreated turf.

Dwarf Bermudagrass Tolerance to Preemergence Herbicides

Preemergence herbicides are applied to prevent summer annual weed infestations in turf, but safety to dwarf-type bermudagrass golf greens has not been determined for many of these materials. Field experiments tested ‘TifEagle’ bermudagrass response to bensulide at 11.2 kg·ha−1 (a.i.), dithiopyr at 0.56 kg·ha−1 (a.i.), napropamide at 2.2 kg·ha−1 (a.i.), oxadiazon at 2.2 kg·ha−1 (a.i.), oxadiazon plus bensulide at 1.7 + 6.7 kg·ha−1 (a.i.), and pendimethalin at 1.7 kg·ha−1 (a.i.). All herbicides reduced root mass from the nontreated, but only losses incited by oxadiazon plus bensulide were acceptable (less than 20%). Dithiopyr, napropamide, and pendimethalin delayed spring greenup in 2003 and 2004, whereas oxadiazon plus bensulide delayed spring greenup in 2004. In greenhouse experiments, ‘TifEagle’ bermudagrass root mass was reduced 19% to 37%, 30% to 33%, 4% to 26%, 28% to 37%, and 24% to 30% from various rates of bensulide, dithiopyr, napropamide, and pendimethalin, respectively. Oxadiazon and oxadiaxon plus bensulide reduced root mass by only 2% to 15% and 15% to 22%, respectively. In another experiment, oxadiazon plus bensulide at 1.7 + 6.7 kg·ha−1 did not injure shoots or roots of ‘Champion’, ‘FloraDwarf’, ‘MiniVerde’, ‘Tifdwarf’, or ‘TifEagle’ bermudagrass. Overall, dwarf-type bermudagrass golf greens do not appear to tolerate mitotic inhibitor preemergence herbicides, whereas oxadiazon or oxadiazon plus bensulide caused minimal injury.

Nutrient Runoff From Bermudagrass Golf Course Fairways After Aerification

Aerification is a common turf management practice, but little is known about its influence on nutrient runoff. The objective of this study was to investigate the influence of hollow-tine aerification on nutrient runoff from a bermudagrass [Cynodon dactylon L. (Pers.)] golf course fairway under natural rainfall conditions. Collection troughs and automated samplers were positioned at the bottom of six 12.3- × 24.4-m plots (5% slope) for surface runoff collection. Three plots received hollow-tine aerification and three plots served as control in a randomized complete block design. Aerification and fertilizer (N at 49 kg/ha/month and P2O5 at 24 kg/ha/month) were applied at the beginning of each month during the study. Runoff samples were collected and tested for NO3-N, NH4-N, and dissolved reactive phosphorus (DRP) after seven natural rainfall events. Aerification delayed runoff by 4 min but did not significantly reduce runoff volume or nutrient losses when compared to control plots. For both treatments, the total amount of applied fertilizer lost to surface runoff was extremely low (<1%). Nutrient concentrations were not statistically different between treatments and had an average concentration of 0.54 mg/liter NO3-N, 0.44 mg/liter NH4-N, and 1.20 mg/liter DRP. The practice of hollow-tine aerification neither reduced nor contributed to a loss of nutrients to natural rainfall runoff.

Turf Covers for Winter Protection of Bermudagrass Golf Greens

Research trials were conducted on a bermudagrass (Cynodon magennissii Hurc. ‘MS-Express’) putting green at the Mississippi State University Golf Course over the winter months of 2000-2001, 2001-2002, and 2002-2003 to evaluate how various turf covers modify surface temperatures and turfgrass growth when applied for temporary cold temperature protection. Average daily maximum, minimum, and mean temperatures were recorded, as well as the average daily range in temperatures under covers. Temperature responses varied with cover composition, permeability, color, and to a lesser extent, thickness. An experimental translucent overwintering blanket provided the highest average daily maximum temperatures, but also had the greatest temperature range, indicating the potential for excessive heating under the cover. A commercially available interwoven polyethylene cover also provided high daily mean soil surface temperatures, but its mean daily minimum temperatures were not significantly different from the uncovered control in two of the three years, apparently indicating much of the energy acquired during the day was lost after sundown. Doubled layers of commercially available white or black polypropylene covers had only slightly increased mean daily minimum temperatures as compared to single layers. All covers provided some degree of potentially desirable temperature modifications, but selection and use would depend on the particular needs of the turf manager.

Quantifying a Daily Light Integral Requirement of a ‘TifEagle’ Bermudagrass Golf Green

‘TifEagle’ bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] is a fine textured hybrid bermudagrass used for golf course putting greens in the subtropical and tropical regions of the world. The growth and performance of TifEagle and other bermudagrass often decline in reduced light environments (RLEs). This study quantified a daily light integral (DLI; mol m−2 d−1) required to maintain commercially acceptable TifEagle bermudagrass maintained under golf green conditions. Three levels of shade, none, low, and high (0, 41, and 92%), were applied to mature TifEagle bermudagrass during morning (sunrise to 1100 h) and afternoon (1500 h to sunset) hours, allowing full irradiance from 1100 to 1500 h to mimic a golf green situation where trees or structures are adjacent to, but rarely directly overhead. The study was performed for 8 wk in June to August 2001 and 2002. An average minimal DLI of 32.6 mol m−2 d−1 was needed to maintain commercially acceptable TifEagle turf quality (TQ ≥ 7). Other plant responses measured included percentage lateral regrowth (RG), total shoot chlorophyll, and total nonstructural carbohydrates (TNC). These responses declined significantly when the DLI ≤ 32.6 mol m−2 d−1 Differences in diurnal shade exposure occurred. High afternoon shade reduced TifEagle bermudagrass TQ, percentage lateral RG, shoot chlorophyll, and TNC by 3.0 rating units and 17, 39, and 27%, respectively, compared with no afternoon shade (NSA). High morning shade reduced TQ, percentage lateral RG, and shoot chlorophyll by 1.5 rating units and 11 and 16%, respectively, compared with no morning shade (NSM). Overall, afternoon shade applications were more detrimental to TifEagle bermudagrass growth and performance compared with morning shade.

Hybrid Bermudagrass ( Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy) Control with Glyphosate and Fluazifop

During bermudagrass golf course renovations, complete removal of existing bermudagrass is imperative for establishing a pure, contaminant-free stand of a new bermudagrass cultivar. Field studies were conducted at the West Florida Research and Education Center near Jay, FL in 2001 and 2002 to evaluate hybrid bermudagrass control. Glyphosate (4.5 kg ai/ha), glyphosate (4.5 kg ai/ha) + ammonium sulfate (1 kg of N per ha), glyphosate (4.5 kg ai/ha) + fluazifop-p-butyl (0.4 kg ai/ha), and glyphosate (4.5 kg ai/ha) + fluazifop-p-butyl (0.4 kg ai/ha) + ammonium sulfate (1 kg of N per ha) were applied sequentially either two or three times at 4-week intervals. At 12 weeks after initial treatment (WAIT) (4 weeks after final herbicide application), glyphosate + fluazifop-p-butyl and glyphosate + fluazifop-p-butyl + ammonium sulfate applied three times provided 99% bermudagrass control. Single-degree-of-freedom contrast analysis indicated that there was a 12% increase in control for three versus two applications at 12 WAIT (P < 0.01). Contrast analysis also indicated a 7% (P < 0.01) increase in bermudagrass control 12 WAIT with fluazifop-p-butyl + glyphosate relative to glyphosate alone. The addition of ammonium sulfate increased control at 4 WAIT (P < 0.05) by 4%, however, no differences in control were observed at 8 and 12 WAIT. Turfgrass managers considering bermudagrass renovation should use three applications of glyphosate + fluazifop-p-butyl at 4.5 + 0.4 kg ai/ha with repeat applications scheduled 4 weeks apart to obtain complete control of the existing bermudagrass.

Identification of denitrifying rhizobacteria from bentgrass and bermudagrass golf greens.

As high rates of nitrogen fertilization are used in turfgrass management, there is a great potential for nitrogen loss. Research on identification of denitrifiers in turfgrass has been limited. Therefore, the aim was to identify denitrifier species and genes from turfgrass roots. Rhizobacteria were isolated from roots of bentgrass and bermudagrass in sand-based United States Golf Association (USGA) golf greens and used for denitrification biochemical analysis. Seventeen per cent (34 isolates) were identified as denitrifiers, 47% were classified as nitrate-reducers and 36% were nondenitrifiers. Identification of species of the denitrifiers was performed by chromatography fatty acid methyl ester (GC-FAME) and16S rDNA analyses. Bacillus and Pseudomonas were the major turfgrass denitrifiers. The two methods showed a 60% agreement at the genus level. Nitrite reductase genes nirK and nirS were detected in 74 and 15% of the denitrifiers, respectively, but not in nondenitrifiers. The nosZ gene encoding nitrous oxide reductase was detected in all the denitrifiers, but also in some nondenitrifiers. To our knowledge, this is the first report for identification of denitrifiers and denitrification-related genes associated with turfgrass roots. These results provide valuable data for future denitrification studies that seek to improve turfgrass nitrogen management for maximum efficiency.

New Options for Annual Bluegrass Control in Overseeded Bermudagrass Putting Greens

Annual bluegrass (Poa annua L.) continues to be a problem in bermudagrass golf greens overseeded with roughstalk bluegrass (Poa trivialis L. `Sabre) due to weed encroachment from adjacent fairways, lack of selective herbicide options, and weed diversity. A 2-year study was conducted on an overseeded `Tifgreen bermudagrass putting green to evaluate effects of herbicide treatments on overseeding and annual bluegrass control. Excellent annual bluegrass control (≥90%) and acceptable turfgrass cover (§70%) was achieved with oxadiazon at 2.2 kg·ha-1 a.i. applied 60 days before overseeding (DBO). Fenarimol (AS) at 4.1 kg·ha-1 a.i. (30 + 15 DBO) followed by 1.4 kg·ha-1 a.i. 60 days after overseeding (DAO) and dithiopyr at 0.6 kg·ha-1 a.i. (60 DBO + 120 DAO) also provided acceptable results. Dithiopyr at 0.4 kg·ha-1 a.i. (30 DBO + 120 DAO), dithiopyr at 0.3 kg·ha-1 a.i. (30 DBO + 30 + 120 DAO), and fenarimol (G) at 2.0 kg·ha-1 a.i. (45 + 30 DBO) followed by 0.8 kg·ha-1 a.i. 60 DAO provided inconsistent annual bluegrass control (55% to 75% in 1999 and 87% to 95% in 2000), but offered acceptable turfgrass cover (§70%) each year. The remaining treatments were generally ineffective and provided &lt;50% annual bluegrass control one or both years. Oxadiazon applied 60 DBO at 2.2 kg·ha-1 a.i. provides an excellent option for annual bluegrass control in overseeded bermudagrass putting greens.

Reduction of Torpedograss (Panicum repens) Canopy and Rhizomes by Quinclorac Split Applications1

Two field experiments were conducted to evaluate the reduction of torpedograss canopy by multiple split applications of quinclorac applied postemergence (POST) to bermudagrass golf course roughs in Florida. In one experiment, quinclorac treatments were reapplied for a second year to the same plots, followed by biomass harvest, to evaluate the reduction of torpedograss rhizomes. Quinclorac sprayed at 1.68 kg/ha/yr visually reduced torpedograss canopy to a varying extent, depending on the number of split applications. The most effective treatment, 0.42 kg/ha quinclorac applied four times each year for 2 yr, reduced torpedograss canopy to 10% compared with 86% torpedograss canopy in the untreated plots, and reduced torpedograss dry weight to 1,570 kg/ha compared with 8,010 kg/ha in the untreated plots. After reapplication for 2 yr with the commercially labeled treatment, quinclorac at 0.84 kg/ha applied twice per year, torpedograss canopy was reduced to 45% and dry weight to 4,640 kg/ha. Visual evaluation of canopy was too optimistic in representing the herbicidal control of torpedograss by quinclorac because torpedograss regrew from rhizomes, and canopy was a relatively small part of the plant. In plots not chemically treated, pachymorph rhizomes were 63%, leptomorph rhizomes were 24%, and leaves were only 13% of the total dry weight of torpedograss.Nomenclature: Quinclorac; hybrid bermudagrass, Cynodon transvaalensis × C. dactylon; torpedograss, Panicum repens L. #3 PANRE.Additional index words: Golf course, turf.Abbreviations: MSO, methylated seed oil; OM, organic matter; POST, postemergence; TPC, Tournament Players Club; WAIT, weeks after initial treatment.

Impact of Overseeding Bermudagrass with Various Amounts of Perennial Ryegrass for Winter Putting Turf

Research was conducted to determine the influence of the rate of seeding perennial ryegrass (Lolium perenne L.) over bermudagrass [Cynodon dactylon (L.) Pers × C. transvaalensis Burtt-Davy] on both the establishment of the ryegrass and the quality of bermudagrass golf greens. Increasing seeding rate from 90 to 180 g·m–2 resulted in more rapid establishment and a linear increase in turf quality. Turf density, as measured by leaf number, displayed linear and quadratic responses to seeding rates, with higher rates producing the greatest leaf numbers. Leaf width declined linearly with seeding rate, suggesting higher putting quality, as did tillers per plant. Spring transition to bermudagrass was slowed at high (150–180 g·m–2) seeding rates, with significantly more ryegrass present in late May. Emergence and growth of bermudagrass were suppressed longer at the higher overseeding rates. We conclude that the choice of seeding rate for ryegrass is a compromise between rapid development of, and maintenance of, quality turf vs. early smooth transition to bermudagrass in the spring.

Comparison of media and diluents for enumeration of aerobic bacteria from Bermuda grass golf course putting greens

To increase our knowledge of soil and rhizosphere bacteria associated with bermuda grass grown on golf courses, a standardized procedure has been developed. Seven aerobic bacterial groups were selected for enumeration. For each group selected, appropriate media were compared to determine which one was best for enumeration of that group. Six diluents were evaluated across all media for the seven bacterial groups. The best diluent was sodium pyrophosphate with glycerol. The following media were best for enumeration: solidified 10% tryptic soy broth for total culturable aerobic bacteria and heat tolerant bacteria; reduced arginine soluble salts medium for actinomycetes; S1 medium for fluorescent pseudomonads; XMSM for Stenotrophomonas maltophilia; Bacto azide blood agar base for gram-positive bacteria; crystal violet agar for gram-negative bacteria.

Use of fungicides to control blue-green algae on Bermuda grass putting-green surfaces

Cyanobacteria, commonly called blue-green algae, are a pest on Bermuda grass ( Cynodon spp.) golf course putting-greens in Florida when excessive water is present. Four fungicide active ingredients: mancozeb, maneb, chlorothalonil and quaternary ammonium salts, were evaluated for control of this pest as preventive and curative treatments. All formulations of mancozeb, maneb and chlorothalonil were effective as preventive applications, but not as curative treatments. The quaternary ammonium salts did not provide any control of blue-green algae. Fungicides would be useful as part of an integrated management program for surface blue-green algae when environmental conditions are conducive for their growth.

Influence of Spring-Applied Herbicides on Bermudagrass (Cynodon dactylon) Greens Overseeded with Roughstalk Bluegrass (Poa trivialis)

Premergence (PRE) herbicides were applied to a bermudagrass golf green overseeded with ‘Laser’ roughstalk bluegrass during 1995 and 1996 to determine their effects on roughstalk bluegrass injury and on the transition from a mixed cool- and warm-season grass back to the permanent bermudagrass. Roughstalk bluegrass tolerated single March applications of trifluralin plus benefin at 2.2 kg/ha, pendimethalin at 3.4 kg/ha, dithiopyr at 0.6 kg/ha, prodiamine at 0.8 kg/ha, bensulide plus oxadiazon at 8.4 kg/ha, and bensulide at 11.2 kg/ha. A single March application of oxadiazon plus benefin at 3.4 kg/ha severely injured (35%) the overseeded turf in 1 yr, but not when 1.7 kg/ha was applied in March and repeated in May. One-half recommended rates of oxadiazon and bensulide plus oxadiazon applied in March did not cause any undesirable injury, but when repeated in May, moderate to severe injury (28 to 33%) occurred in June. Oryzalin at ≥ 1.1 kg/ha, benefin plus oryzalin at ≥ 1.1 kg/ha, and oxyfluorfen plus oryzalin at ≥ 1.7 kg/ha severely injured (≥ 35%) roughstalk bluegrass. The rate of transition of mixed roughstalk bluegrass and bermudagrass back to permanent bermudagrass was not affected by any of the PRE herbicides except when oryzalin was applied alone or in combination with benefin or oxyfluorfen.