Identification of Waitea circinata as a Pathogen of the Moss Bryum argenteum var. argenteum on a Golf Course Fairway

Waitea circinata Warcup and Talbot (also referred to as W. circinata var. circinata) is an important fungal pathogen of amenity turfgrasses and is especially problematic on Poa annua in putting greens in the late spring or early summer. The pathogen was first identified in 2005 from Japan and has since been seen widely throughout the United States (1,2). On occasion, the pathogen has been observed attacking creeping bentgrass (Agrostis stolonifera) but is typically less virulent. Disease symptoms include prominent yellow rings appearing throughout established turf and moderate leaf necrosis. In the summer of 2012, moss from a section of fairway on a golf course in Edwards, CO was observed to be rapidly killed by a fungal pathogen producing copious amounts of aerial mycelium and appearing similar to Waitea microscopically. Aerial mycelium was transferred to acidified potato dextrose agar (PDA) (1 ml lactic/L). After 1 day at 25°C, mycelia were transferred to PDA. After 2 weeks, plates were covered with white aerial mycelium and separate, spherical, 0.5-mm diameter, salmon-colored sclerotia, which turned dark brown within a few days and were produced submerged throughout the media. Spores were never produced and right-angled branching of mycelia, characteristic of Waitea, was observed in mature cultures. Mycelial plugs were incubated in nutrient broth and DNA was extracted using a MoBio Power Plant DNA extraction kit. Amplification of ribosomal ITS sequences with ITS4 and ITS5 resulted in a 100% identity match with GenBank sequence HM807352, W. circinata var. circinta (3). To demonstrate pathogenicity on Bryum argenteum, unaffected moss from the submitted sample (identified as B. argenteum var. argenteum via 100% sequence identity with the published GenBank sequence GU907062) was removed from the originally submitted sample and placed in separate growth chambers at 95% humidity and 21, 26, and 31°C. An additional experiment employed local B. agenteum plants collected from the URI Kingston, RI campus. Agar plugs from the isolated W. circinata were placed on top of the moss and within 2 days the fungus had caused complete mortality at all three temperatures. The experiment was also undertaken using the same environmental conditions with 5-week-old annual bluegrass (P. annua) and creeping bentgrass cv. A4 grown from seed. Plants were inoculated with infected rye grains at 31, 26, and 21°C. After 1 week, the P. annua plants showed significant mortality at 26 and 31°C with little infection at 21°C and the A. stolonifera plants showed moderate mortality at 26°C and little infection at the other two temperatures. All experiments utilized an additional uninoculated control treatment that showed no moss/turf necrosis or mortality. Experiments were all repeated once and used three replicates per experiment. While moss is not intentionally cultivated on golf courses, it does occur with regularity and often presents itself as a difficult pest to manage. This particular isolate of W. circinata has identical ribosomal and physiological characteristics of the reported P. annua pathogen but can attack one moss species and may be a possible candidate for selective biological control of moss in golf course settings. It is unclear how widespread moss pathogenicity is within W. circinata. References: (1) E. N. Njambere et al. Plant Dis. 95:78 2011. (2) T. Toda et al. Plant Dis. 89:536, 2005. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications, 1990.

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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 Waitea circinata var. circinata Causing Brown Ring Patch on Poa trivialis in California

Plant Disease ◽

10.1094/pdis-91-12-1687a ◽

2007 ◽

Vol 91 (12) ◽

pp. 1687-1687 ◽

Cited By ~ 2

Author(s):

C. M. Chen ◽

G. W. Douhan ◽

F. P. Wong

Keyword(s):

Its Region ◽

Creeping Bentgrass ◽

The United States ◽

Negative Control ◽

Early Summer ◽

Putting Greens ◽

First Report ◽

Initial Symptoms ◽

Poa Trivialis ◽

Waitea Circinata

Rough bluegrass (Poa trivialis L.) is a C3 (cool-season) turfgrass used on golf course putting greens. It is often used to overseed C4 (warm-season) turf for fall through early-summer use. In March 2007, at maximium daytime air temperatures of approximately 30 to 35°C, irregular, thin, yellow rings approximately 10 to 20 cm in diameter were reported on P. trivialis in putting greens from two golf courses in the Coachella Valley of southern California. Affected plants had a blight of the leaves and stems and a rot of the crown, with initial symptoms being a yellowing of the tissue followed by the development of a dark, water-soaked appearance of the whole plant. Plants turned reddish brown as the water-soaked tissue dessicated. A Rhizoctonia-like fungus was found to be colonizing the leaves, stems, and upper roots and thatch. Three isolates were obtained from the diseased turf samples. All were identified as Waitea circinata var. circinata based on colony morphology (2) and rDNA internal transcribed spacer (ITS) region sequences (1). The sequences of the three isolates were more than 99% similar to those of W. circinata var. circinata deposited in the NCBI database (1,2). To confirm pathogenicity, each isolate was inoculated onto 4-week-old P. trivialis (2 mg of seed per cm2) grown in 10-cm-diameter pots containing steam-sterilized UC-mix at 28°C. Five 8-mm-diameter plugs of each isolate were taken from 7-day-old cultures grown on potato dextrose agar (PDA) and placed in direct contact with the bases of the stems. The pots were then incubated in a moist chamber at 28°C. Five noncolonized PDA plugs were used as a negative control. Three pots were used for each of the three isolates and the check treatment. For all isolates, chlorosis of leaf and stems were observed 5 days after inoculation and the tissue appeared water soaked after 7 days with the production of abundant aerial mycelia being observed. All plants, except the negative controls, died after 10 days. W. circinata var. circinata was reisolated from symptomatic tissue from the inoculated plants. W. circinata var. circinata was previously reported as the causal agent of brown ring patch on creeping bentgrass (Agrostis palustris) in Japan (2) and as a pathogen of annual bluegrass (P. annua) in the United States (1). To our knowledge, this is the first report of W. circinata var. circinata infecting P. trivialis in California. References: (1) K. de la Cerda et al. Plant Dis. 91:791, 2007. (2) T. Toda et al. Plant Dis. 89:536, 2005.

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

Plant Disease ◽

10.1094/pdis-05-20-1031-re ◽

2021 ◽

pp. PDIS-05-20-1031 ◽

Cited By ~ 1

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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Identification of a New Waitea circinata Variety Causing Basal Leaf Blight of Seashore Paspalum

Plant Disease ◽

10.1094/pdis-03-10-0204 ◽

2011 ◽

Vol 95 (5) ◽

pp. 515-522 ◽

Cited By ~ 9

Author(s):

S. J. Kammerer ◽

L. L. Burpee ◽

P. F. Harmon

Keyword(s):

Cynodon Dactylon ◽

Warm Season ◽

Creeping Bentgrass ◽

Leaf Blight ◽

Golf Course ◽

New Variety ◽

Seashore Paspalum ◽

Basal Leaf ◽

Poa Trivialis ◽

Waitea Circinata

Seashore paspalum (Paspalum vaginatum) is a saline-tolerant, warm-season turfgrass species popular for golf course use in tropical and subtropical climates. A new variety of Waitea circinata (proposed as W. circinata var. prodigus) is described as the causal agent of basal leaf blight, a novel disease of seashore paspalum. Foliar necrosis and canopy thinning of seashore paspalum were observed on three different golf course fairways in Florida over an 18-month period. Five isolates with profuse, pink to yellow mycelia and small, salmon-colored or yellow to light-brown sclerotia were cultured from diseased turf foliage. Isolates grew rapidly over a temperature range of 25 to 35°C and were initially identified as an uncharacterized variety of W. circinata. Internal transcribed spacer sequences of rDNA from the isolates were compared with sequences from previously described W. circinata varieties. The paspalum isolates formed a phylogenetic clade that was distinct from the other W. circinata varieties. Pathogenicity was confirmed on ‘SeaDwarf’ and ‘SeaIsle Supreme’ seashore paspalum, ‘Penncross’ creeping bentgrass (Agrostis stolonifera), ‘Senesta’ bermudagrass (Cynodon dactylon), and ‘Dark Horse’ roughstalk bluegrass (Poa trivialis). The geographical distribution and potential impact of basal leaf blight is unknown. However, the range of potential turfgrass hosts and environmental conditions conducive for disease development suggest that the pathogen may infect other species in addition to seashore paspalum.

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First Report of Brown Ring Patch Caused by Waitea circinata var. circinata on Poa trivialis in Florida

Plant Disease ◽

10.1094/pdis-92-11-1586a ◽

2008 ◽

Vol 92 (11) ◽

pp. 1586-1586

Author(s):

N. Flor ◽

P. Harmon ◽

L. Datnoff ◽

R. Raid ◽

R. Nagata

Keyword(s):

Cynodon Dactylon ◽

Aerial Mycelium ◽

Creeping Bentgrass ◽

Internal Transcribed Spacers ◽

Wheat Grains ◽

First Report ◽

Poa Trivialis ◽

Putting Green ◽

Plastic Bag ◽

Waitea Circinata

Brown ring patch is a newly described disease of cool-season turfgrass first reported in Japan on creeping bentgrass (Agrostis palustris) (2) and later reported in California on annual bluegrass (Poa annua) (1). The disease is characterized by either patches or rings of discolored to blighted turfgrass that can range from a few centimeters to a meter in diameter. Affected turfgrass plants turn chlorotic and can be blighted from the crown to the leaf tips. Blight symptoms have been associated with fluffy white-to-cream aerial mycelium after extended incubation of the sample. Symptoms including patches of blighted turfgrass approximately 10 cm in diameter were observed on roughstalk bluegrass (Poa trivialis) that had been overseeded onto a dormant ‘Tifdwarf’ bermudagrass (Cynodon dactylon) putting green in Palatka, FL. A sample was submitted by the superintendent in June 2005 because symptoms were confused with dollar spot and a fungicide resistance issue was suspected. The sample produced abundant aerial mycelium after incubation. The pathogen was isolated on potato dextrose agar amended with rifampicin (100 ppm) and streptomycin (100 ppm) from Poa plants surface disinfested with 70% ethanol for 30 s. Colony and sclerotia morphology were consistent with Waitea circinata var. circinata as previously described (1,2). The teleomorph W. circinata var. circinata was not observed on plant material or culture plates. Amplified fragments of rDNA including internal transcribed spacers from the isolate were sequenced bidirectionally from four bacterial clones. The consensus sequences (GenBank Accession Nos. FJ029103, FJ029104, FJ029105, and FJ029106) matched with 99% homology (99% sequence overlap) isolate TRGC1.1 of W. circinata var. circinata described by Wong, NCBI Accession No. DQ900586 (1). Pots of ‘Cypress’ roughstalk bluegrass that were 1 week postemergence were inoculated with the pathogen using 10 infested wheat grains. Plants were incubated at 25°C in a sealed plastic bag with a moist paper towel in the bottom. Hyphae grew from the grains and colonized the grass. Individual plants began to turn chlorotic within 3 days and greater than 90% of the turf in pots was dead after 1 week. The fungus was reisolated from affected plants. Control pots were inoculated with uninfested wheat grains and showed no disease symptoms after 1 week. Inoculations were repeated twice more with the same results. To our knowledge, this is the first report of brown ring patch on P. trivialis in Florida. References: (1) K. A. de la Cerda et al. Plant Dis. 91:791, 2007. (2) 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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Dose responses of silvery-thread moss (Bryum argenteum) to carfentrazone-ethyl

Weed Technology ◽

10.1017/wet.2021.42 ◽

2021 ◽

pp. 1-24

Author(s):

Zane Raudenbush ◽

Steven J. Keeley ◽

Cole Thompson ◽

Mithila Jugulam

Keyword(s):

Dose Response ◽

Creeping Bentgrass ◽

Field Studies ◽

Golf Course ◽

Short Term ◽

Putting Greens ◽

San Luis ◽

Bryum Argenteum ◽

Petri Dishes ◽

Dose Responses

Abstract Carfentrazone-ethyl is one of few herbicides labeled for control of silvery-thread moss (STM) in golf course putting greens, but common use rates are up to three times higher than for broadleaf weeds. Our objective was to determine the efficacy of a single postemergence application of carfentrazone-ethyl for STM control in greenhouse and field dose response studies. In the greenhouse, carfentrazone-ethyl was applied at 0, 14, 28, 56, 112, and 224 g ai ha−1 to pots containing established STM and creeping bentgrass. Percent gametophyte injury was visually estimated at 14, 28, 49, and 77 d after treatment (DAT). Shoot viability was determined by excising shoots from treated pots and plating them in petri dishes containing sand. The 28 and 49 DAT ED90 (dose required to cause 90% gametophyte injury) were 26.8 and 54.3 g ha−1, respectively; both of these doses are substantially lower than the label rates for long- and short-term control, respectively. All doses reduced the viability of transplanted shoots at 10 DAT compared to untreated STM; however, regrowth occurred in all petri dishes by 17 DAT. Field studies were initiated in Manhattan, Kansas and San Luis Obispo, California to corroborate greenhouse results. Averaged across locations, carfentrazone-ethyl applied at 56 and 112 g ha−1 caused 76% and 84% STM injury at 14 DAT, but quickly reduced to 45% and 48% STM injury by 28 DAT, respectively. In greenhouse and field studies, STM recovery did not occur until after 2 wk after treatment (WAT), which indicates the label-stipulated application interval of 2 wk is too short. Our research suggests 56 g ha−1 can provide similar burndown control of STM as compared to the highest label rate (112 g ha−1), and turfgrass managers should consider extending the reapplication interval to 3 or 4 wk when moss recovery is observed.

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

Plant Disease ◽

10.1094/pdis-08-10-0606 ◽

2011 ◽

Vol 95 (1) ◽

pp. 78-78 ◽

Cited By ~ 1

Author(s):

E. N. Njambere ◽

B. B. Clarke ◽

S. A. Bonos ◽

J. A. Murphy ◽

R. Buckley ◽

...

Keyword(s):

New Jersey ◽

Creeping Bentgrass ◽

The United States ◽

Agrostis Stolonifera ◽

Poa Annua ◽

Its Sequencing ◽

First Report ◽

Annual Bluegrass ◽

Pathogenicity Tests ◽

Waitea Circinata

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 Cabbage Head Rot Caused by Fusarium avenaceum in Poland

Plant Disease ◽

10.1094/pdis-05-14-0507-pdn ◽

2014 ◽

Vol 98 (12) ◽

pp. 1741-1741 ◽

Cited By ~ 2

Author(s):

J. Robak ◽

A. Czubatka ◽

A. Czajka ◽

U. Smolinska

Keyword(s):

Aerial Mycelium ◽

Colony Growth ◽

The United States ◽

Control Treatment ◽

Its2 Region ◽

Academic Press ◽

Laboratory Manual ◽

First Report ◽

Head Rot ◽

Excised Tissue

Cabbage (Brassica oleracea L. var. capitata L.) is an important crop in Poland. Symptoms of a disease affecting cabbage were observed in 2012 and 2013 both in mid-August during the growing season and during storage in January and February. The disease affected about 30 to 40% of crops grown on ~9,000 ha over three locations: Charsznica in south Poland and Bedlno and Skierniewice in central Poland. Circular, watery lesions ranging from 10 to 60 mm in diameter on the surface of affected cabbage heads included whitish aerial mycelium that developed orange sporodochia in the center of each lesion. After 2 to 3 weeks, infection covered each entire cabbage head. A fungal pathogen was isolated from the orange lesions and from infected internal tissue. After sterilization of the excised tissue in 70% ethanol, the sections were each rinsed twice with sterilized water, dried on sterilized filter paper, and plated onto potato dextrose agar (PDA). Isolations consistently yielded morphologically homogeneous fungal colonies with abundant aerial mycelium that ranged from yellow to brownish yellow. The fungus produced pigmentation that changed the agar medium from dark yellow to brownish-burgundy. The mean colony growth was 66 mm after 7 days at 25°C. The fungus formed macroconidia, but microconidia and chlamydospores were not observed. Macroconidia were slender, slightly falcate, usually 3- to 5-septate, 44.7 to 60.7 × 3.7 to 5.5 μm, and formed in abundant orange sporodochia. On PDA, the isolates lost the ability to form sporodochia. Morphological and cultural features were typical of those of F. avenaceum (Fries) Saccardo (2). Koch's postulates were conducted to establish pathogenicity of each of four of the isolates on cabbage heads of the cv. Jaguar F1 (Bejo Seeds, Poland). The outer leaf of each head was inoculated with an 8-mm-diameter PDA plug colonized by the appropriate isolate (four cabbage heads/isolate), and the heads stored in a growth chamber at 25°C. After 5 to 7 days, lesions similar to those observed on naturally infested cabbage were observed on all the inoculated cabbage leaves. Four cabbage heads treated similarly with water as a control treatment remained symptomless. The experiment was repeated. DNA extracted from two of the four isolates was subjected to a PCR assay with primers ITS5 and ITS4 (4) for species identification based on the ITS1 and ITS2 sequences of ribosomal DNA (rDNA). The two sequences differed by 1 bp in the ITS2 region and had 100% identity with ITS sequences of F. avenaceum Accession Nos. AY147283 and AY147285 in GenBank. The sequences were deposited in GenBank as KM189440 and KM189441. Descriptions of fusarium head rot of cabbage in the United States (1) and Canada (3) were consistent with these observations in Poland. To our knowledge, this is the first report of F. avenaceum causing head rot of cabbage in Poland and in Europe. References: (1) H. R. Dillard and A. C. Cobb. Phytopathology 96:30. 2006. (2) J. F. Leslie and B. A. Summerell. Page 132 in: The Fusarium Laboratory Manual, Blackwell Publishing, Hoboken, NJ, 2006. (3) R. D. Peters et al. HortSci. 42:737. 2007. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

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