scholarly journals Preventive Control of Pythium Root Dysfunction in Creeping Bentgrass Putting Greens and Sensitivity of Pythium volutum to Fungicides

Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1275-1280 ◽  
Author(s):  
J. P. Kerns ◽  
M. D. Soika ◽  
L. P. Tredway
Keyword(s):  
Fungicidal Activity ◽  
Creeping Bentgrass ◽  
Disease Suppression ◽  
Preventive Control ◽  
Putting Greens ◽  
In Vitro Sensitivity ◽  
Putting Green ◽  
Field Efficacy

Pythium root dysfunction (PRD), caused by Pythium volutum, has been observed on golf course putting greens established with creeping bentgrass in the southeastern United States since 2002. To evaluate preventative strategies for management of this disease, a 3-year field experiment was conducted in Pinehurst, NC on a ‘G-2’ creeping bentgrass putting green. Fungicide treatments were applied twice in the fall (September and October) and three times in the spring (March, April, and May) in each of the 3 years. Applications of pyraclostrobin provided superior preventative control compared with the other fungicides tested. Azoxystrobin and cyazofamid provided moderate control of PRD in two of three seasons. Experiments were conducted to determine whether the disease suppression provided by pyraclostrobin was due to fungicidal activity or physiological effects on the host. In vitro sensitivity to pyraclostrobin, azoxystrobin, fluoxastrobin, cyazofamid, mefenoxam, propamocarb, and fluopicolide was determined for 11 P. volutum isolates and 1 P. aphanidermatum isolate. Isolates of P. volutum were most sensitive to pyraclostrobin (50% effective concentration [EC50] value = 0.005), cyazofamid (EC50 = 0.004), and fluoxastrobin (EC50= 0.010), followed by azoxystrobin (EC50 = 0.052), and mefenoxam (EC50 = 0.139). P. volutum isolates were not sensitive to fluopicolide or propamocarb. Applications of pyraclostrobin did not increase the foliar growth rate or visual quality of creeping bentgrass in growth-chamber experiments. This work demonstrates that fall and spring applications of pyraclostrobin, azoxystrobin, and cyazofamid suppress the expression of PRD symptoms during summer and that field efficacy is related to the sensitivity of P. volutum to these fungicides.

scholarly journals Evaluation of Preventive Fungicide Applications for Fairy Ring Control in Golf Putting Greens and In Vitro Sensitivity of Fairy Ring Species to Fungicides

Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 1001-1007 ◽  
Author(s):  
G. L. Miller ◽  
M. D. Soika ◽  
L. P. Tredway
Keyword(s):  
Soil Temperature ◽  
Field Experiments ◽  
Chemical Properties ◽  
Creeping Bentgrass ◽  
Fungicide Sensitivity ◽  
Putting Greens ◽  
Growth Assay ◽  
Ring Species ◽  
The Impact

Fairy ring species induce symptoms on putting greens mostly indirectly, by modifying the soil physical or chemical properties. Therefore, preventive rather than curative fungicide applications may be more effective in managing fairy ring. Two field experiments were conducted on a creeping bentgrass research green to evaluate fairy ring control from preventive fungicide applications. A 3-year study investigated the optimal rate and soil temperature-based timing of a preventive application of triadimefon and tebuconazole. A 2-year study evaluated the impact of irrigation timing and fungicide + surfactant tank mixtures on the efficacy of preventive applications of triadimefon and triticonazole. Fungicide-treated plots in both studies exhibited less fairy ring severity than untreated plots. Data suggest that a 5-day average soil temperature range of 13 to 16°C may be suitable for initiating preventive applications. Symptoms occurred earlier in plots treated with a surfactant tank mix than in those treated with fungicide alone. Irrigation timing had no effect on fungicide performance. The sensitivity of 16 isolates representing major fairy ring species to flutolanil, propiconazole, tebuconazole, triadimefon, and triticonazole was determined with a mycelial growth assay. No significant differences in fungicide sensitivity were detected among species. Isolates had significantly higher 50% effective concentration values for triadimefon than for the other fungicides tested.

Creeping Bentgrass (Agrostis stolonifera) Putting Green Tolerance to Bispyribac-Sodium

2009 ◽  
Vol 23 (3) ◽  
pp. 425-430 ◽  
Author(s):  
Patrick E. McCullough ◽  
Stephen E. Hart
Keyword(s):  
Growth Inhibition ◽  
Field Experiments ◽  
Creeping Bentgrass ◽  
Agrostis Stolonifera ◽  
Root Weight ◽  
Putting Greens ◽  
Annual Bluegrass ◽  
Greenhouse Experiments ◽  
Chelated Iron ◽  
Putting Green

Bispyribac-sodium is an efficacious herbicide for annual bluegrass control in creeping bentgrass fairways, but turf tolerance and growth inhibition may be exacerbated by low mowing heights on putting greens. We conducted field and greenhouse experiments to investigate creeping bentgrass putting green tolerance to bispyribac-sodium. In greenhouse experiments, creeping bentgrass discoloration from bispyribac-sodium was exacerbated by reductions in mowing height from 24 to 3 mm, but mowing height did not influence clipping yields or root weight. In field experiments, discoloration of creeping bentgrass putting greens was greatest from applications of 37 g/ha every 10 d, compared to 74, 111, or 222 g/ha applied less frequently. Chelated iron effectively reduced discoloration of creeping bentgrass putting greens from bispyribac-sodium while trinexapac-ethyl inconsistently reduced these effects. Overall, creeping bentgrass putting greens appear more sensitive to bispyribac-sodium than higher mowed turf, but chelated iron and trinexapac-ethyl could reduce discoloration.

scholarly journals Occurrence and Molecular Identification of Azoxystrobin-Resistant Colletotrichum cereale Isolates from Golf Course Putting Greens in the Southern United States

Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 751-757 ◽  
Author(s):  
Joseph R. Young ◽  
Maria Tomaso-Peterson ◽  
Lane P. Tredway ◽  
Karla de la Cerda
Keyword(s):  
United States ◽  
Creeping Bentgrass ◽  
Amino Acid Sequences ◽  
Golf Course ◽  
Southern United States ◽  
Common Disease ◽  
Putting Greens ◽  
Qoi Fungicides ◽  
Colletotrichum Cereale

Turfgrass anthracnose, caused by Colletotrichum cereale (≡C. graminicola), has become a common disease of creeping bentgrass and annual bluegrass putting greens throughout the southern United States. Strobilurin (QoI) fungicides such as azoxystrobin are single-site mode-of-action fungicides applied to control C. cereale. In vitro bioassays with azoxystrobin at 0.031 and 8 μg/ml incorporated into agar were performed to evaluate the sensitivity of 175 isolates collected from symptomatic turfgrasses in Alabama, Mississippi, North Carolina, Tennessee, and Virginia. Three sensitivity levels were identified among C. cereale isolates. Resistant, intermediately resistant, and sensitive isolates were characterized by percent relative growth based on the controls with means of 81, 23, and 4%, respectively, on media containing azoxystrobin at 8 μg/ml. The molecular mechanism of resistance was determined by comparing amino acid sequences of the cytochrome b protein. Compared with sensitive isolates, C. cereale isolates exhibiting QoI resistance had a G143A substitution, whereas isolates expressing intermediate resistance had a F129L substitution. C. cereale isolates displaying azoxystrobin resistance in vitro were not controlled by QoI fungicides in a field evaluation. The dominance of QoI-resistant C. cereale isolates identified in this study indicates a shift to resistant populations on highly managed golf course putting greens.

scholarly journals Creeping Bentgrass Quality following Preemergence and Postemergence Herbicide Applications

HortScience ◽  
1994 ◽  
Vol 29 (8) ◽  
pp. 880-883 ◽  
Author(s):  
B. Jack Johnson
Keyword(s):  
Field Experiments ◽  
Creeping Bentgrass ◽  
Monosodium Salt ◽  
Putting Green ◽  
Methylarsonic Acid ◽  
Turfgrass Quality ◽  
June July ◽  
Postemergence Herbicides ◽  
Quinolinecarboxylic Acid

Three field experiments were conducted to determine if several preemergence and postemergence herbicides were safe to apply to creeping bentgrass (Agrostis stolonifera L. `Penncross') maintained at putting green height. When dithiopyr was applied at preemergence in late February or early March, the emulsifiable concentrate formulation (≤1.7 kg·ha-1) and granular formulation (≤1.1 kg·ha-1) did not reduce the quality or cover of creeping bentgrass. Applied at preemergence, bensulide plus oxadiazon at 6.7 + 1.7 kg·ha-1 and 13.4 + 3.4 kg·ha-1 reduced turfgrass quality for 2 to 3 weeks and 8 weeks after treatment, respectively. When MON 12051 and monosodium salt of methylarsonic acid (MSMA) (≤0.14 and ≤2.2 kg·ha-1, respectively) were applied at postemergence to creeping bentgrass in early June, the reduction in turfgrass quality varied from slight to moderate for 1 to 2 weeks, but turfgrass fully recovered with no effect on turfgrass cover. Quinclorac applied at postemergence in early June at ≥0.6 kg·ha-1 severely reduced creeping bentgrass quality and cover for ≥8 weeks. Diclofop at 0.6 kg·ha-1 applied to creeping bentgrass in June, July, or August maintained consistently higher quality and cover ratings than when applied at ≥1.1 kg·ha-1. Diclofop applied at 0.6 kg·ha-1 in June and repeated at the same rate in July reduced quality of creeping bentgrass less than when applied at 1.1 kg·ha-1 at any date. Chemical names used: O,O-bis (1-methylethyl) S-{2-[(phenylsulfonyl)amino]ethyl} phosphorodithioate (bensulide); (±)-2-[4-(2,4-dichlorophenoxy)phenoxy]propanoic acid (diclofop); S,S-dimethyl-2-(difluoromethyl)-4-(2-methylpropyl)-6-(trifluoromethyl)-3,5-pyridinedicarbothioate (dithiopyr); methyl-5-{[(4,6-dimethoxy-2-pyrimidinyl)amino] carbonylaminosulfonyl}-3-chloro-1-methyl-1-H-pyrazol-4-carboxylate (MON 12051); 3-[2,4-dicloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3H)-one (oxadiazon); 3,7-dicloro-8-quinolinecarboxylic acid (quinclorac).

scholarly journals Loss of Putting Greens-grade Fertilizer Granules Due to Mowing

HortScience ◽  
2001 ◽  
Vol 36 (6) ◽  
pp. 1123-1126 ◽  
Author(s):  
Charles F. Mancino ◽  
Dianne Petrunak ◽  
Douglas Wilkinson
Keyword(s):  
Water Solubility ◽  
Creeping Bentgrass ◽  
Fertilizer Application ◽  
Application Rate ◽  
N Fertilizer ◽  
Putting Greens ◽  
Total Percentage ◽  
K Fertilizer ◽  
Putting Green ◽  
The Difference

The loss of fertilizer granules collected in turf clippings during routine putting green mowing has not been determined. The objective of this study was to quantify the amounts of greens-grade granular potassium (K) and nitrogen (N) fertilizers collected during the routine mowing of a `Pennlinks' creeping bentgrass (Agrostis palustris Huds.) putting green. In the first study, five K-containing granular fertilizers were applied at K rates of 2.43 and 4.86 g·m-2. A second study was also performed with six granular Ncontaining fertilizers and one liquid N fertilizer applied at an N rate of 4.86 g·m-2. Both studies were performed twice. Irrigation (6.4 mm) was applied immediately after each fertilizer application and again on the following day. These two irrigations, plus additional irrigation and rain, resulted in each study receiving about 2.54 cm of water over each nineday study period. Mowing and clipping collection using a walk-behind greens mower set to cut at 3.96 mm began two days after treatment (2 DAT) and continued until 9 DAT. The clippings were oven-dried and separated from the fertilizer using a small pneumatic seed cleaner. Collected fertilizer was weighed and expressed as a percentage of the fertilizer applied. Liquid N fertilizer loss was estimated to be the difference between clipping N content of treated plots and untreated controls. Total K fertilizer loss was: UHS Signature 15-0-30 (15.3% to 22.9%) > Lebanon Isotek 11-3-22 (8.7% to 10.7%) > Scott's Contec 13-2-26 (4.9% to 7.4%) > Lesco Matrix 12-0-22 (0.1% to 0.4%) = Lesco Matrix 5-0-28 (0.1% to 0.5%). Signature was the only fertilizer significantly affected by rate and a greater percentage of loss occurred at the lower K application rate. Most loss occurred during the first and second mowing events with small amounts of fertilizer found in clippings from later mowings. The two Lesco materials were not found in clippings after the first mowing. Nitrogen fertilizer granule loss was also greatest with the first and second mowings. Total percentage of losses were IBDU 31-0-0 (75.4%) > Polyon 41-0-0 (70.8%)> Milorganite 6-2-0 (55.7%) > Nutralene 40-0-0 (47.0%) > UHS Signature (19.3%) > Isotek 11-3-22 (9.5%) > N-Sure Pro 30-0-0 (1.9%). In both studies, fertilizer loss appeared to be most related to water-solubility of the fertilizer, but size and density might also be factors.

scholarly journals Use of High-pressure Injection to Alleviate Type-I Fairy Ring Symptoms in Turfgrass

2005 ◽  
Vol 15 (1) ◽  
pp. 169-172 ◽  
Author(s):  
M.A. Fidanza ◽  
P.F. Colbaugh ◽  
M.C. Engelke ◽  
S.D. Davis ◽  
K.E. Kenworthy
Keyword(s):  
High Pressure ◽  
Root Zone ◽  
Creeping Bentgrass ◽  
Golf Course ◽  
Type I ◽  
Putting Greens ◽  
Pressure Injection ◽  
Spray Method ◽  
Putting Green ◽  
High Pressure Injection

Fairy ring is a common and troublesome disease of turfgrasses maintained on golf course putting greens. Type-I fairy ring is especially destructive due to the development of hydrophobic conditions in the thatch and root zone, thus contributing to turfgrass injury and loss. The objective of this 2-year field study was to evaluate the application and novel delivery method of two fungicides and a soil surfactant for curative control of type-I fairy ring in a 20-year-old creeping bentgrass [Agrostis palustris (synonym A. stolonifera)] putting green. In both years, all treatments were applied twice on a 28-day interval. In 1998, flutolanil and azoxystrobin fungicides were applied alone and in combination with Primer soil surfactant by a conventional topical spray method, and fungicides without Primer applied via high-pressure injection (HPI). Acceptable type-I fairy ring control was observed in plots treated with flutolanil plus Primer, HPI flutolanil, azoxystrobin alone, azoxystrobin plus Primer, or HPI azoxystrobin. In 1999, treatments were HPI flutolanil, HPI flutolanil plus Primer, HPI azoxystrobin, HPI water only, and aeration only. Acceptable type-I fairy ring control was observed in plots treated with HPI flutolanil plus Primer or HPI azoxystrobin. HPI of fungicides alone or in combination with a soil surfactant may be a viable option for alleviating type-I fairy ring symptoms on golf course putting greens.

scholarly journals Moss Control on Creeping Bentgrass Greens with Standard and Alternative Approaches

HortScience ◽  
2010 ◽  
Vol 45 (4) ◽  
pp. 654-659 ◽  
Author(s):  
Megan M. Kennelly ◽  
Timothy C. Todd ◽  
Derek M. Settle ◽  
Jack D. Fry
Keyword(s):  
Sodium Bicarbonate ◽  
Organic Fertilizer ◽  
Creeping Bentgrass ◽  
Threshold Level ◽  
Organic Fertilizers ◽  
Dollar Spot ◽  
Putting Greens ◽  
Management Regime ◽  
Alternative Approach ◽  
Putting Green

Moss is common on creeping bentgrass (Agrostis stolonifera L.) putting greens, and more control options are needed. Spot treatment of sodium bicarbonate (44.2 g·L−1) was compared with broadcast sprays of carfentrazone-ethyl (50.5 or 101 g a.i./ha), chlorothalonil (8.2 or 12.8 kg a.i./ha) and a tank mixture of chlorothalonil, mancozeb, and thiram (8.2, 9.8, and 11.5 kg a.i./ha) in 2006 in Lemont, IL. Sodium bicarbonate suppressed moss growth equally as the conventional products. These results led to further experiments in 2008 in which moss suppression was evaluated within standard and alternative putting green management regimes in Manhattan, KS, and Lemont, IL. The standard approach included spring and fall applications of carfentrazone-ethyl (101 g a.i./ha) for moss control, biweekly applications of urea (46N–0P–0K) at 15 kg N/ha, and applications of chlorothalonil (8.2 kg a.i./ha) on a 14-day interval. Conversely, the alternative approach included spring and fall spot treatments of sodium bicarbonate (44.2 g·L−1) for moss control, biweekly applications of a natural organic fertilizer (8N–1P–3K) to provide nitrogen at 15 kg N/ha, and applications of chlorothalonil (8.2 kg a.i./ha) only when dollar spot reached a predetermined threshold level. Standard and alternative regimes were compared at both 3.2- and 4.0-mm mowing heights; synthetic and organic fertilizers applied alone without pest control approaches were included as controls. In Kansas and Illinois, moss coverage using the alternative management regime was not significantly different from that on greens managed using the standard regime. In Kansas, moss severity at a 3.2 mm was 1.6-fold higher than at the 4.0-mm height. In Illinois, sodium bicarbonate suppressed moss equivalently to the carfentrazone-ethyl treatment, and in the fertilizer-only controls, mowing at 3.2 versus 4.0 mm led to more moss coverage. These studies demonstrate that moss can be effectively suppressed on greens using spot applications of sodium bicarbonate and reduced moss encroachment is possible with higher mowing heights.

Effect of Benefin and DCPA on Overseeded Grasses Maintained as Putting Greens

Weed Science ◽  
1973 ◽  
Vol 21 (6) ◽  
pp. 528-531 ◽  
Author(s):  
G. E. Coats ◽  
C. Y. Ward ◽  
E. L. McWhirter
Keyword(s):  
Cynodon Dactylon ◽  
Lolium Multiflorum ◽  
Creeping Bentgrass ◽  
Italian Ryegrass ◽  
Agrostis Palustris ◽  
Putting Greens ◽  
Red Fescue ◽  
Poa Trivialis ◽  
Putting Green ◽  
Green Conditions

Overseeded rough bluegrass (Poa trivialisL. ‘Danish common’) and Italian ryegrass (Lolium multiflorumLam. ‘Gulf’) maintained under putting green conditions were more susceptible to benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) and DCPA (dimethyl tetrachloroterephthalate) than creeping bentgrass (Agrostis palustrisHud. ‘Penn-cross’), red fescue (Festuca rubraL. ‘Dawson’), or perennial ryegrass (Lolium perenneL. ‘Medalist II’). February applications of 1.68 or 3.36 kg/ha of benefin and 6.72 or 13.44 kg/ha of DCPA caused significantly more discoloration and reductions in density than equivalent rates applied in March or April. Benefin was more injurious than DCPA to all overseeded species as judged by quality or density. DCPA caused significant delays in the breaking of dormancy of bermudagrass [Cynodon dactylon(L.) Pers. ‘Tifdwarf’].

scholarly journals Dollar Spot Suppression on Creeping Bentgrass in Response to Repeated Foliar Nitrogen Applications

Plant Disease ◽  
2021 ◽  
pp. PDIS-05-20-1031 ◽  
Author(s):  
Ronald Townsend ◽  
Michael D. Millican ◽  
Damon Smith ◽  
Ed Nangle ◽  
Kurt Hockemeyer ◽  
...  
Keyword(s):  
Calcium Nitrate ◽  
Creeping Bentgrass ◽  
The United States ◽  
Fertilizer Application ◽  
N Fertilization ◽  
Disease Suppression ◽  
Golf Course ◽  
Dollar Spot ◽  
Putting Greens ◽  
The Impact

Dollar spot is caused by the fungus Clarireedia spp. and is the most economically important disease of golf course turfgrass in temperate regions of the United States. Previous research has demonstrated that nitrogen (N) fertilization may reduce dollar spot severity, but the results have been inconsistent, and the impact of N as part of repeated foliar fertilization applications to golf course putting greens remains unclear. Two independent trials were replicated in Madison, Wisconsin and Glenview, Illinois in the 2015, 2016, and 2017 growing seasons. The objective of the first trial was to evaluate the effect of four different N rates applied as urea (4.9, 9.8, 19.4, and 29.3 kg N/ha applied every 2 weeks) on dollar spot severity, and the objective of the second trial was to evaluate the effect of three N sources (calcium nitrate, ammonium sulfate, and ammonium nitrate applied every 2 weeks) on dollar spot severity. Results from the N rate trial at both locations indicated that only the highest (29.3 kg N/ha) rate consistently reduced dollar spot severity relative to the nontreated control. Nitrogen source had minimal and inconsistent impacts on dollar spot severity based on location and year. Although these results show that meaningful reductions in dollar spot severity can be achieved by manipulating N fertilizer application rates, the rate of N needed for disease suppression may be impractical for most superintendents to apply and result in undesirable nontarget impacts.

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