First Report of Brown Ring Patch Caused by Waitea circinata var. circinata on Poa annua and Agrostis stolonifera in New Jersey

Waitea circinata var. circinata was first reported as the causal agent of brown ring patch on annual bluegrass (Poa annua L.) in the United States in 2007 (2). In early April to mid-June of 2009, circular to irregularly shaped yellow rings resembling symptoms of this disease were observed on an annual bluegrass putting green at Rutgers University in North Brunswick, NJ. Severely infected foliage eventually turned brown as the disease progressed. During the same time period, similar disease symptoms were observed on creeping bentgrass (Agrostis stolonifera L.) from a golf course in Bedminster Township, NJ. The disease reappeared in both locations in April of 2010. Five additional samples with similar symptoms on creeping bentgrass and annual bluegrass were received at Rutgers Diagnostic Laboratory from Paramus, Madison, Allamuchy, and Farmingdale, NJ between late April and early May of 2010. Portions of diseased leaf and sheath tissue that displayed symptoms of the disease were disinfested for 1 min in 0.5% NaOCl, rinsed with sterile distilled water, and plated on potato dextrose agar (PDA) amended with 50 mg/liter of streptomycin sulfate. At the first sign of fungal growth, single hyphal tips were transferred to PDA. After 1 week at 25°C, white-to-orange mycelial colonies formed in culture and eventually turned brown with age. Minute sclerotia (≤3 mm), which followed the same color development pattern, formed within 10 days. These features are consistent with those described of W. circinata var. circinata (2,3). The internal transcribed spacer (ITS) region of the ribosomal RNA gene was amplified using primer pair ITS1/ITS4 and sequenced with ITS4 (GenBank Accession Nos. HQ166065 to HQ166071). BLASTn analysis of the ITS sequences showed a 99 to 100% similarity to W. circinata var. circinata sequences deposited in GenBank (1,2). Pathogenicity tests were conducted in 2010 using 6-week-old creeping bentgrass seedlings cv. Declaration inoculated with colonized oat grain that had been autoclaved and then infested with the Bedminster Township isolate. Eight colonized oat grains were uniformly spread around the crowns of seedlings grown in 10-cm-diameter pots. Control plants were treated with autoclaved grain. Plants were incubated at 25°C and high humidity maintained by misting the plants three times per day. Within 3 days postinoculation, foliage near infested grain turned chlorotic. All foliage in pots became completely blighted and spherical orange-brown sclerotia were observed on leaf sheaths by the eighth day. W. circinata var. circinata was consistently reisolated from inoculated plants (as confirmed by isolate morphology and ITS sequencing) but not from control plants. The ITS sequence data, morphological characters of the isolates, and pathogenicity tests demonstrate that W. circinata var. circinata is present in New Jersey. To our knowledge, this is the first report of W. circinata var. circinata infecting turfgrass in New Jersey. References: (1) C. M. Chen et al. Plant Dis. 93:906, 2009. (2) K. A. de la Cerda et al. Plant Dis. 91:791, 2007. (3) T. Toda et al. Plant Dis. 89:536, 2005.

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First Report of Brown Ring Patch Caused by Waitea circinata var. circinata on Poa annua in Pennsylvania

Plant Disease ◽

10.1094/pdis-93-9-0962a ◽

2009 ◽

Vol 93 (9) ◽

pp. 962-962

Author(s):

M. A. Fidanza ◽

S. J. McDonald ◽

F. P. Wong ◽

T. H. Mysliwiec ◽

R. M. Averell

Keyword(s):

Its Region ◽

Creeping Bentgrass ◽

Poa Annua ◽

Fungal Mycelium ◽

First Report ◽

Annual Bluegrass ◽

Bright Yellow ◽

Agar Plug ◽

Putting Green ◽

Waitea Circinata

In late May and early June of 2008, bright yellow, thin, irregular-shaped rings that were 10 to 15 cm in diameter were observed on 30% of an annual bluegrass (Poa annua L.) putting green in Coopersburg, PA. The 46-year-old silt-loam soil green was mowed at a 3.1-mm height and consisted of 80% annual bluegrass and 20% creeping bentgrass (Agrostis stolonifera L., unknown cultivar). During the appearance of ring symptoms, the overall minimum and maximum daily air temperature ranged from 19.9 to 31.1°C, respectively, along with 40.3 mm of total rain accumulation. In late May, only individual affected annual bluegrass plants exhibited a bright yellow chlorosis of upper and lower leaf blades and crown. By early June, affected annual bluegrass plants appeared dark brown and water soaked, turning reddish brown and then tan as they dessicated, wilted, and died. Fungal mycelium, similar in appearance to Rhizoctonia spp., was found among affected leaf blades and within the thatch layer. A single fungal isolate was obtained from affected annual bluegrass tissue and grown on potato dextrose agar (PDA) plus 0.1 g of chloramphenicol per liter. Fungal colony morphology and sequencing of the ITS1F/ITS4-amplified rDNA internal transcribed spacer (ITS) region confirmed the isolate as Waitea circinata var. circinata, with ≥90% similar homology match to published W. circinata var. circinata ITS sequences (GenBank Accession No. DQ900586) (2,4). To confirm pathogenicity, the isolate was inoculated onto 6-week-old annual bluegrass (0.001 g of surface-sterilized seed per cm2) grown in 5- × 5-cm2 plastic pots containing autoclaved 70% sand and 30% potting soil. Plants were maintained daily at a 4.0-mm height using a hand-held scissors. One 6-mm-diameter plug of the isolate was removed from the active edge of a 5-day-old culture grown on PDA and placed in contact with the lower leaf blades of the target plants. Four pots were inoculated with the isolate and four pots were inoculated with an isolate-free agar plug for each of two experimental runs. After inoculation, all pots were placed in a moist chamber at 28°C. In both experiments leaf blade chlorosis and a modest amount of aerial mycelium was observed in all four isolate-introduced pots at 5 to 7 days after inoculation. Symptoms were similar to those expressed in the field, and by 21 to 28 days, all isolate-infected plants died, whereas the noninoculated plants remained healthy and nonsymptomatic. W. circinata var. circinata was reisolated from symptomatic tissue of those inoculated plants and again confirmed by colony traits and rDNA ITS region sequences. This pathogen was reported previously as the causal agent of brown ring patch on annual bluegrass and rough bluegrass (Poa trivialis L.) in the western United States. (1,2). To our knowledge, this is the first report of brown ring patch in Pennsylvania. The economic impact of this disease could be significant since intensive fungicide practices are used to produce high-quality putting green surfaces in the region (3). References: (1) C. Chen et al. Plant Dis. 91:1687, 2007. (2) K. de la Cerda et al. Plant Dis. 91:791, 2007. (3) J. Kaminski and F. Wong. Golf Course Mgmt. 75(9):98, 2007. (4) T. Toda et al. Plant Dis. 89:536, 2005.

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First Report of Brown Ring Patch Caused by Waitea circinata var. circinata on Poa annua in Wisconsin and Minnesota

Plant Disease ◽

10.1094/pdis-94-9-1165a ◽

2010 ◽

Vol 94 (9) ◽

pp. 1165-1165 ◽

Cited By ~ 1

Author(s):

J. P. Kerns ◽

P. L. Koch ◽

B. P. Horgan ◽

C. M. Chen ◽

F. P. Wong

Keyword(s):

Sequence Similarity ◽

Aerial Mycelium ◽

Creeping Bentgrass ◽

Poa Annua ◽

Minor Amount ◽

Molecular Characteristics ◽

Putting Greens ◽

First Report ◽

Annual Bluegrass ◽

Waitea Circinata

In summer of 2008, two turfgrass samples were submitted to the Turfgrass Diagnostic Lab at the University of Wisconsin–Madison. The samples were from golf courses in Beaver Dam, WI on 12 June and Minneapolis, MN on 14 July. Both samples were collected from 40-year-old native soil putting greens mowed at 3.2 mm that had received annual sand topdressing since 1992. The putting greens were a mixture of approximately 75% annual bluegrass (Poa annua L.) and 25% creeping bentgrass (Agrostis stolonifera L.) Stand symptoms observed in the field were bright yellow, sunken rings that were approximately 5 cm thick and 15 to 35 cm in diameter. Some rings were incomplete, giving a scalloped appearance. Affected plants were severely chlorotic and lacked any discrete lesions or spots. Symptoms were more prominent on annual bluegrass than creeping bentgrass. Upon incubation of samples at room temperature in a moist chamber for 24 h, fungal mycelia with septations and right-angle branching were observed in the foliage and thatch layer. Two isolates were obtained from affected annual bluegrass in each sample. Isolations were performed by washing affected leaves in 0.5% NaOCl solution for 2 min, blotting the tissue dry, and plating the tissue on potato dextrose agar (PDA) amended with chloramphenicol (0.05 g/liter), streptomycin (0.05 g/liter), and tetracycline (0.05 g/liter). After incubation for 2 days at 23°C, isolates were transferred and maintained on PDA. All four isolates had multinucleate hyphae and displayed sclerotial characteristics similar to those reported for Waitea circinata var. circinata (2). Sequencing the ITS1F/ITS4-amplified rDNA internal transcribed spacer (ITS) region confirmed the isolates as W. circinata var. circinata, with ≥99% sequence similarity to published W. circinata var. circinata ITS sequences (GenBank Accession No. FJ755849) (1,2,4). To confirm pathogenicity, isolates were inoculated onto 6-week-old annual bluegrass (True Putt/DW184) grown in 10-cm-diameter pots containing calcined clay (Turface; Profile Products LLC., Buffalo Grove, IL). Two 4-mm-diameter agar plugs for each isolate were removed from the margins of 3-day-old colonies grown on PDA and placed near the soil surface to ensure contact with the lower leaf blades. Each isolate was placed in four separate pots to have four replicated tests per isolate, and four noninfested pots were utilized as negative controls. All pots were placed in moist chambers at 28°C with a 12-h light/dark cycle. Within 4 to 6 days, inoculated plants exhibited severe chlorosis and a minor amount of aerial mycelium was observed. Inoculated plants became necrotic after 15 to 20 days, while the noninoculated plants remained healthy. W. circinata var. circinata was reisolated from inoculated plants and its identity was confirmed by morphological and molecular characteristics. This pathogen was previously reported as a causal agent of brown ring patch of creeping bentgrass in Japan and annual bluegrass in the western United States (2,4). To our knowledge, this is the first report of brown ring patch in Minnesota and Wisconsin. Intensive fungicide practices are needed to control brown ring patch; therefore, this disease could have significant economic impact throughout the Upper Midwest (3). References: (1) C. M. Chen et al. Plant Dis. 93:906, 2009 (2) K. de la Cerda et al. Plant Dis. 91:791, 2007. (3) J. Kaminski and F. Wong. Golf Course Manage. 75(9):98, 2007. (4) T. Toda et al. Plant Dis. 89:536, 2005.

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First Report of Brown Ring Patch on Poa annua Caused by Waitea circinata var. circinata in West Virginia

Plant Disease ◽

10.1094/pdis-04-10-0274 ◽

2010 ◽

Vol 94 (11) ◽

pp. 1379-1379

Author(s):

S. J. McDonald ◽

R. M. Averell ◽

M. E. Glass ◽

H. M. Young ◽

T. H. Mysliwiec ◽

...

Keyword(s):

West Virginia ◽

Aerial Mycelium ◽

Creeping Bentgrass ◽

Poa Annua ◽

Golf Course ◽

First Report ◽

5.8S Rdna ◽

Annual Bluegrass ◽

Agar Plug ◽

Waitea Circinata

In mid-November 2009, thin, yellow, and irregular-shaped scalloped rings 10 to 25 cm in diameter were observed on 5 to 10% of a golf course putting green in Charles Town, WV. The 20-year-old USGA-specification sand-based green was mowed at 3.1-mm height and consisted of 60% annual bluegrass (Poa annua L.) and 40% creeping bentgrass (Agrostis stoloniferous L. ‘Putter’). Minimum and maximum daily air temperature ranged from 2 to 22°C, respectively, with 38 mm of rainfall during the appearance of rings symptoms. Only affected annual bluegrass plants exhibited a peculiar yellow chlorosis of the upper and lower leaves. A single fungal isolate was obtained from active mycelium found within symptomatic annual bluegrass leaves and grown on potato dextrose agar (PDA) amended with chloramphenicol (0.1 g/liter). Fungal colony morphology (i.e., light yellow with irregular-shaped 2- to 4-mm-diameter sclerotia first appearing off-white but progressing to brown by 21 to 28 days in culture) and sequencing of the internal transcribed spacer (ITS) 5.8S rDNA region with primers ITS1 and ITS4 confirmed the isolate as Waitea circinata var. circinata (Warcup & Talbot) with ≥99% sequence identity with GenBank Accession No. FJ755889 (1,2,4). To confirm pathogenicity, a 6-mm-diameter plug of the isolate was removed from the expanding edge of a 4-day-old culture grown on PDA and placed in contact with the lower leaves of 12-week-old annual bluegrass (0.001 g of surface-sterilized seed per cm2) grown in 5- × 5-cm plastic pots of autoclaved 85% sand and 15% potting soil. Six pots were inoculated with the isolate and six pots were inoculated with an isolate-free agar plug and then placed in a moist chamber at 28°C. Leaf chlorosis and aerial mycelium was observed in all six inoculated pots 8 to 10 days after inoculation, and symptoms were similar to those expressed in the field. All noninoculated plants remained healthy and asymptomatic. W. circinata var. circinata was reisolated from symptomatic leaves and again confirmed by colony traits and sequencing of the ITS-5.8S rDNA region and submitted as GenBank Accession No. HM807582. To our knowledge, this is the first report of brown ring patch in West Virginia and could be economically important because of intensive fungicide practices used to maintain high-quality putting greens on golf courses (3). References: (1) C. Chen et al. Plant Dis. 91:1687, 2007. (2) K. de la Cerda et al. Plant Dis. 91:791, 2007. (3) J. Kaminski and F. Wong. Golf Course Manage. 75:98, 2007. (4) T. Toda et al. Plant Dis. 89:536, 2005.

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First Report of Brown Ring Patch Caused by Waitea circinata var. circinata on Poa annua in Virginia

Plant Disease ◽

10.1094/pdis-93-4-0426a ◽

2009 ◽

Vol 93 (4) ◽

pp. 426-426 ◽

Cited By ~ 2

Author(s):

S. Kammerer ◽

P. F. Harmon ◽

S. McDonald ◽

B. Horvath

Keyword(s):

Creeping Bentgrass ◽

Internal Transcribed Spacers ◽

Poa Annua ◽

Golf Course ◽

Mixed Stands ◽

Putting Greens ◽

First Report ◽

Annual Bluegrass ◽

Plastic Bag ◽

Waitea Circinata

Brown ring patch was first described as a disease of cool-season turfgrass on creeping bentgrass (Agrostis palustris) (4) in Japan and later reported in California on annual bluegrass (Poa annua) (2). Brown ring patch symptoms were observed beginning in December 2007 through spring 2008 on 6 of 18 putting greens on a golf course in Reston, VA. Symptoms included yellow rings and patches of blighted turfgrass on the mixed stands of creeping bentgrass (A. palustris) and primarily annual bluegrass (Poa annua). Chlorosis and blight occurred predominantly on P. annua. A turfgrass sample was received from a consultant in April 2008, and disease severity on affected greens was estimated to be 40%. After incubating for 2 days in a moist chamber, Rhizoctonia-like aerial mycelia were observed. The pathogen was isolated on water agar and potato dextrose agar amended with thiophanate-methyl (100 mg/L), rifampicin (100 mg/L), and ampicillin (500 mg/L) from P. annua plants that had been surface sterilized with 70% ethanol for 15 s. Colony and sclerotia morphology were consistent with Waitea circinata var. circinata as previously described (2,4). Hyphae were stained with aniline blue and multiple nuclei were observed per cell. The teleomorph was not observed on plant material or in culture. Amplified fragments of rDNA including internal transcribed spacers from the isolate were amplified in three bacterial clones and sequenced bidirectionally (GenBank Accession Nos. FJ154894, FJ154895, and FJ154896) using primers ITS1/ITS4 (2,4). The consensus sequences matched, with 99% homology and 99% sequence overlap, isolate TRGC1.1 of W. circinata var. circinata (GenBank Accession No. DQ900586) (2). Annual bluegrass was not available for use in performing Koch's postulates, but previous studies have shown that W. circinata var. circinata is pathogenic to roughstalk bluegrass (P. trivialis) (1,3). Pots of P. trivialis cv. Cypress that were 1 week postemergence were inoculated with seven wheat grains that had been autoclaved and then infested with the isolate. Plants were incubated at 25°C in a sealed plastic bag with a moist paper towel on the bottom. Hyphae grew from the grains and colonized the grass. Individual plants began to turn chlorotic within 3 days, and more than 80% of the turf in pots was dead after 1 week. Control pots were inoculated with autoclaved wheat seed and showed no disease symptoms after 1 week. Inoculations were repeated twice more with the same results. W. circinata var. circinata was reisolated from affected plants in all replications of the test. To our knowledge, this is the first report of brown ring patch in Virginia. Additional research is needed to assess the prevalence and importance of this disease on golf course putting greens in Virginia. References: (1) C. M. Chen et al. Plant Dis. 91:1687, 2007. (2) K. A. de la Cerda et al. Plant Dis. 91:791, 2007. (3) N. Flor et al. Plant Dis. 92:1586, 2008. (4) T. Toda et al. Plant Dis. 89:536, 2005.

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Temperature Influences Creeping Bentgrass (Agrostis stolonifera) and Annual Bluegrass (Poa annua) Response to Bispyribac-Sodium

Weed Technology ◽

10.1614/wt-05-010r2.1 ◽

2006 ◽

Vol 20 (3) ◽

pp. 728-732 ◽

Cited By ~ 24

Author(s):

Patrick E. McCullough ◽

Stephen E. Hart

Keyword(s):

New Jersey ◽

New Brunswick ◽

Creeping Bentgrass ◽

Agrostis Stolonifera ◽

Poa Annua ◽

Growth Chamber ◽

Annual Bluegrass ◽

Temperature Regimes ◽

Leaf Chlorosis ◽

Research Complex

Bispyribac-sodium is a POST herbicide that selectively controls annual bluegrass in creeping bentgrass, but inconsistent results with seasonal applications are believed to occur from temperature influences on bispyribac-sodium efficacy. Growth chamber experiments at the New Jersey Experimental Greenhouse Research Complex, New Brunswick, NJ, investigated three temperature regimes on ‘L-93’ creeping bentgrass and annual bluegrass responses to bispyribac-sodium. Annual bluegrass and creeping bentgrass exhibited contrasting responses to bispyribac-sodium as temperature increased from 10 to 30 C. Regressions of 4 week after treatment (WAT) data revealed as temperature increased from 10 to 30 C, required bispyribac-sodium rates for 50% clipping reduction (CR50) of annual bluegrass decreased from 85 to 31 g ai/ha and required rates for 50% leaf chlorosis decreased from greater than 296 to 98, indicating increased herbicidal efficacy at higher temperatures. In contrast, required bispyribac-sodium rates for creeping bentgrass CR50increased from 200 to greater than 296 as temperature increased from 10 to 30 C. Bispyribac-sodium discolored creeping bentgrass 0 to 20% at 20 and 30 C and discoloration increased 10 to 50% at 10 C. Thus, warmer temperatures (20 and 30 C) increase bispyribac-sodium efficacy for annual bluegrass control with minimal bentgrass discoloration; however, cooler temperatures (10 C) have minimal efficacy on annual bluegrass and increase bentgrass chlorosis.

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Absorption, Translocation, and Metabolism of Amicarbazone in Annual Bluegrass (Poa annua), Creeping Bentgrass (Agrostis stolonifera), and Tall Fescue (Festuca arundinacea)

Weed Science ◽

10.1614/ws-d-12-00136.1 ◽

2013 ◽

Vol 61 (2) ◽

pp. 217-221 ◽

Cited By ~ 15

Author(s):

Jialin Yu ◽

Patrick E. McCullough ◽

William K. Vencill

Keyword(s):

Tall Fescue ◽

Festuca Arundinacea ◽

Creeping Bentgrass ◽

Agrostis Stolonifera ◽

Poa Annua ◽

Physiological Effects ◽

Cool Season ◽

Foliar Absorption ◽

Annual Bluegrass

Amicarbazone controls annual bluegrass in cool-season turfgrasses but physiological effects that influence selectivity have received limited investigation. The objective of this research was to evaluate uptake, translocation, and metabolism of amicarbazone in these species. Annual bluegrass, creeping bentgrass, and tall fescue required < 3, 56, and 35 h to reach 50% foliar absorption, respectively. At 72 h after treatment (HAT), annual bluegrass and creeping bentgrass translocated 73 and 70% of root-absorbed14C to shoots, respectively, while tall fescue only distributed 55%. Annual bluegrass recovered ≈ 50% more root-absorbed14C in shoots than creeping bentgrass and tall fescue. Creeping bentgrass and tall fescue metabolism of amicarbazone was ≈ 2-fold greater than annual bluegrass from 1 to 7 d after treatment (DAT). Results suggest greater absorption, more distribution, and less metabolism of amicarbazone in annual bluegrass, compared to creeping bentgrass and tall fescue, could be attributed to selectivity of POST applications.

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Annual Bluegrass (Poa Annua) Control in Creeping Bentgrass (Agrostis Stolonifera) Putting Greens with Bispyribac-sodium

Weed Technology ◽

10.1614/wt-06-023 ◽

2007 ◽

Vol 21 (2) ◽

pp. 426-430 ◽

Cited By ~ 7

Author(s):

Travis C. Teuton ◽

Christopher L. Main ◽

John C. Sorochan ◽

J. Scott McElroy ◽

Thomas C. Mueller

Keyword(s):

Creeping Bentgrass ◽

Agrostis Stolonifera ◽

Poa Annua ◽

Putting Greens ◽

Annual Bluegrass

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First Report of Typhula Blight on Agrostis stolonifera and Poa annua in Italy

Plant Disease ◽

10.1094/pdis.2003.87.7.875c ◽

2003 ◽

Vol 87 (7) ◽

pp. 875-875 ◽

Cited By ~ 1

Author(s):

P. Titone ◽

M. Mocioni ◽

A. Garibaldi ◽

M. L. Gullino

Keyword(s):

Agrostis Stolonifera ◽

Northern Italy ◽

Potato Dextrose Agar ◽

Poa Annua ◽

Golf Course ◽

Pathogenicity Test ◽

Potato Dextrose Broth ◽

First Report ◽

Pathogenicity Tests ◽

Typhula Incarnata

During January 2002, Agrostis stolonifera and Poa annua turfgrasses on a golf course in Avigliana (northern Italy) exhibited 10- to 45-cm-diameter circular patches when the snow melted from the greens, tees, and fairways. Many patches coalesced to form large areas of strawcolored blighted turfgrass. At the patch margin, infected plants were covered with white-to-gray mycelium. Plants within patches were matted and appeared slimy with mycelium and sclerotia that were light pink, irregularly shaped, and less than 5 mm in diameter. Isolation from infected leaves on potato dextrose agar, supplemented with 100 mg/l of streptomycin sulfate, consistently yielded a fungus with mycelial, sclerotia, and cultural characteristics of Typhula incarnata (1). Pathogenicity tests were performed by spraying a suspension of mycelium and sclerotia, prepared by chopping mycelium and sclerotia produced in potato dextrose broth, onto 8-week-old A. stolonifera plants grown in plastic trays (45 × 30 cm). Trays were maintained at 0°C for 8 weeks in the dark. Blight symptoms developed on inoculated plants after 6 weeks. Non-inoculated plants remained healthy. The pathogen was reisolated from inoculated plants, and the pathogenicity test was repeated once. Typhula blight incited by T. incarnata was reported in Scandinavian countries and in several European countries including Holland, Germany, Austria, and Switzerland (1). To our knowledge, this is the first report of Typhula blight on turfgrass in Italy. Reference: (1) J. D. Smith et al. 1989. Fungal Diseases of Amenity Turf Grasses. E & FN Spong Ltd, London.

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Effects of Rolling and Sand Topdressing on Dollar Spot Severity in Fairway Turfgrass

HortTechnology ◽

10.21273/horttech04272-19 ◽

2019 ◽

Vol 29 (4) ◽

pp. 394-401 ◽

Cited By ~ 1

Author(s):

Thomas O. Green ◽

John N. Rogers ◽

James R. Crum ◽

Joseph M. Vargas ◽

Thomas A. Nikolai

Keyword(s):

Cost Saving ◽

Creeping Bentgrass ◽

Agrostis Stolonifera ◽

Poa Annua ◽

Mixed Stand ◽

Dollar Spot ◽

Annual Bluegrass ◽

Spot Activity ◽

Effective Cost

Results suggest that sand topdressing was more consistent at reducing dollar spot (Clarireedia jacksonii) in fairway turfgrass more so than rolling. This practice could be an effective cost-saving alternative to reduce frequent fungicide applications. Research was conducted from 2011 to 2014 on a simulated golf fairway and examined dollar spot severity responses in a mixed-stand of creeping bentgrass (Agrostis stolonifera) and annual bluegrass (Poa annua ssp. reptans) to sand topdressing and rolling. Treatments consisted of biweekly sand topdressing, rolling at three frequencies (one, three, or five times weekly), a control, and three replications. Infection was visually estimated. Sand topdressing significantly (P < 0.05) reduced disease up to 50% at the peak of the dollar spot activity in 2011, 2013, and 2014. Results on the effects of rolling on dollar spot were inconsistent.

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Nitrogen Influences Bispyribac-Sodium Efficacy and Metabolism in Annual Bluegrass (Poa annua) and Creeping Bentgrass (Agrostis stolonifera)

Weed Technology ◽

10.1614/wt-d-10-00136.1 ◽

2011 ◽

Vol 25 (3) ◽

pp. 385-390

Author(s):

Patrick E. McCullough ◽

Stephen E. Hart ◽

Thomas Gianfagna ◽

Fabio Chaves

Keyword(s):

Nitrogen Fertilization ◽

Laboratory Experiments ◽

Field Experiments ◽

Creeping Bentgrass ◽

Agrostis Stolonifera ◽

Poa Annua ◽

Annual Bluegrass ◽

Increased Sensitivity ◽

Sodium Metabolism ◽

Nitrogen Treatments

Field and laboratory experiments were conducted in New Jersey to investigate the influence of nitrogen on annual bluegrass and creeping bentgrass metabolism and responses to bispyribac-sodium. In field experiments, withholding nitrogen during the test period increased sensitivity of both grasses to bispyribac-sodium, and grasses fertilized biweekly had darker color on most rating dates. Nitrogen generally increased annual bluegrass tolerance to bispyribac-sodium at 74 g ha−1but not at 148 g ha−1. Creeping bentgrass was influenced by nitrogen at both herbicide rates. In laboratory experiments, weekly nitrogen treatments increased14C-bispyribac-sodium metabolism in both grasses compared to unfertilized plants. Annual bluegrass metabolized approximately 50% less herbicide regardless of nitrogen regime compared to creeping bentgrass. Overall, routine nitrogen fertilization appears to improve annual bluegrass and creeping bentgrass tolerance to bispyribac-sodium, which may be attributed to higher metabolism.

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