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Brown patch, caused by Rhizoctonia solani, is a destructive disease on tall fescue. Compared with R. solani, Rhizoctonia zeae causes indistinguishable symptoms in the field but varies in geographic distribution. This may contribute to geographic variability observed in the resistance response of improved brown patch–resistant cultivars. This study examined R. solani and R. zeae susceptibility of four cultivars, selected based on brown patch performance in the National Turfgrass Evaluation Program (NTEP), and nine plant introductions (PIs). Twenty genotypes per PI/cultivar were evaluated by using four clonal replicates in a randomized complete block design. Plants were inoculated under controlled conditions with two repetitions per pathogen. Disease severity was assessed digitally in APS Assess, and analysis of variance and correlations were performed in SAS 9.3. Mean disease severity was higher for R. solani (65%) than for R. zeae (49%) (P = 0.0137). Interaction effects with pathogen were not significant for PI (P = 0.0562) but were for genotype (P < 0.001). Moderately to highly resistant NTEP cultivars compared with remaining PIs exhibited lower susceptibility to R. zeae (P < 0.0001) but did not differ in susceptibility to R. solani (P = 0.7458). Correlations between R. solani and R. zeae disease severity were not significant for either PI (R = 0.06, P = 0.8436) or genotype (R = 0.11, P = 0.09). Breeding for resistance to both pathogens could contribute to a more geographically stable resistance response. Genotypes were identified with improved resistance to R. solani (40), R. zeae (122), and both pathogens (26).

Tall fescue (Festuca arundinacea Shreb.) has exceptional utility as a low maintenance lawn in the transition zone. However, during the summer smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] infestations can reduce the aesthetic value and function of the turf and lead to a thinning of the tall fescue stand, noticeable after the crabgrass plants have senesced. Research was conducted to evaluate the impact of mowing height and nitrogen fertility on smooth crabgrass plant counts and tall fescue cover in Virginia Beach, VA. Plots were mowed at either 6 cm (2.5 in) or 10 cm (4 in) and received 49, 171, or 220 kg of nitrogen annually per hectare (44, 152, and 196 lb.A−1). Mowing at 10 cm with the highest level of fertility resulted in the most turfgrass cover among all the treatment combinations. Mowing at 10 cm as opposed to 6 cm resulted in less smooth crabgrass plants, regardless of nitrogen fertilization rate.Index words: fertilization, turfgrass, weed control.Species used in this study: Smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.]; tall fescue [Festuca arundinacea Shreb. synonym Schedonorus phoenix (Scop.) Holub].

Poor annual bluegrass control was reported in golf course roughs following treatment with prodiamine (1120 gaiha−1) and glyphosate (840 gaeha−1) during hybrid bermudagrass dormancy. Research was conducted to determine if this annual bluegrass phenotype was resistant to both prodiamine and glyphosate and to determine the efficacy of herbicide mixtures for controlling this phenotype in the field. In PRE or POST dose-response experiments, 9 to 31 times more prodiamine or glyphosate was needed to control (or reduce dry biomass of) this resistant phenotype by 50% compared to an herbicide-susceptible phenotype. Moreover, glyphosate-susceptible plants accumulated 50% more shikimic acid (898 mgkg−1) 6 d after treatment than those resistant to glyphosate (394 mgkg−1). October (fall) applications of herbicide mixtures containing trifloxysulfuron, simazine, S-metolachlor, or mesotrione controlled this resistant annual bluegrass phenotype 84 to 98% in April (spring), with no differences detected among treatments. Our findings document the second instance of annual bluegrass evolving multiple resistance in a managed turfgrass system. However, several herbicide mixtures can be used to effectively manage this resistant phenotype.Nomenclature: glyphosate; mesotrione; prodiamine; simazine; S-metolachlor; trifloxysulfuron; annual bluegrass, Poa annua L.; hybrid bermudagrass, Cynodon dactylon×Cynodon transvaalensis Burtt-Davy.Control limitado de Poa annua fue reportado en “roughs” de campos de golf despues de tratamientos con prodiamine (1120 g ai ha−1) y glyphosate (840 gaeha−1) durante el periodo de dormancia del cesped bermuda hibrido. Se realizo una investigacion para determinar si este fenotipo de P. annua era resistente a prodiamine y glyphosate y para determinar la eficacia de mezclas de herbicidas para controlar este fenotipo en el campo. En experimentos de respuesta a dosis con herbicidas PRE o POST, se necesito de 9 a 31 veces mas prodiamine o glyphosate para controlar (o reducir la biomasa seca) de este fenotipo resistente en 50% en comparacion a un fenotipo susceptible a estos herbicidas. Ademas, plantas susceptibles a glyphosate acumularon 50% mas acido shikimic (898 mg kg−1) 6 d despues del tratamiento que plantas resistentes a glyphosate (394 mg kg−1). Aplicaciones en Octubre (otono) de mezclas de herbicidas que contenian trifloxysulfuron, simazine, S-metolachlor, o mesotrione controlaron este fenotipo resistente de P. annua 84 a 98% en Abril (primavera), sin detectarse diferencias entre estos tratamientos. Nuestros resultados documentan la segunda instancia de P. annua que evoluciona resistencia multiple en un sistema manejado de cespedes. Sin embargo, varias mezclas de herbicidas pueden ser usadas para manejar efectivamente este fenotipo resistente.

Brown patch, caused by

Tall fescue has great utility as a low maintenance turfgrass in the northern and transition zone regions of the United States. A factor limiting tall fescue utility is its susceptibility to the pathogen Rhizoctonia solani Kuhn, the causal agent of foliar brown patch. Chitinase activity has been positively correlated with resistance to R. solani in other plant species. A chitinase assay was developed for tall fescue. Three tall fescue cultivars with differing agronomic qualities and brown patch susceptibility as well as a resistant hybrid bluegrass cultivar were inoculated with R. solani in a greenhouse humidity chamber. Chitinase activity 48 hours after inoculation was negatively correlated with percent brown patch severity 10 days after inoculation. ‘Jaguar’ tall fescue was the most tolerant to R. solani and exhibited the highest chitinase activity before and after inoculation. No significant increase in chitinase activity was observed in the other tall fescue cultivars following R. solani inoculation. Identifying tall fescue cultivars expressing high amounts of chitinase activity could be important for developing brown patch-tolerant tall fescue cultivars.

Dollar spot is one of the most common diseases of golf course turfgrass and numerous fungicide applications are often required to provide adequate control. Weather-based disease warning systems have been developed to more accurately time fungicide applications; however, they tend to be ineffective and are not currently in widespread use. The primary objective of this research was to develop a new weather-based disease warning system to more accurately advise fungicide applications to control dollar spot activity across a broad geographic and climactic range. The new dollar spot warning system was developed from data collected at field sites in Madison, WI and Stillwater, OK in 2008 and warning system validation sites were established in Madison, WI, Stillwater, OK, Knoxville, TN, State College, PA, Starkville, MS, and Storrs, CT between 2011 and 2016. A meta-analysis of all site-years was conducted and the most effective warning system for dollar spot development consisted of a five-day moving average of relative humidity and average daily temperature. Using this model the highest effective probability that provided dollar spot control similar to that of a calendar-based program across the numerous sites and years was 20%. Additional analysis found that the 20% spray threshold provided comparable control to the calendar-based program while reducing fungicide usage by up to 30%, though further refinement may be needed as practitioners implement this warning system in a range of environments not tested here. The weather-based dollar spot warning system presented here will likely become an important tool for implementing precision disease management strategies for future turfgrass managers, especially as financial and regulatory pressures increase the need to reduce pesticide usage on golf course turfgrass.

Brown patch (Rhizoctonia solani Kuhn), a destructive disease of tall fescue (Festuca arundinacea Schreb.), is typically evaluated visually. The subjectivity of visual evaluations may be reduced using technology like digital image analysis (DIA). This study compared DIA and visual evaluations for accuracy and precision of brown patch ratings of glasshouse grown tall fescue plants. Across four experiments, 112 plants were inoculated with R. solani. Disease was rated visually and using DIA-WP (digital image analysis whole plant canopy). In two experiments, disease evaluations were replicated using three images and three visual evaluations per pot. Absolute error was calculated as the difference between actual disease severity [calculated using an individual leaf DIA method previously quantified as highly predictive of actual brown patch disease severity on tall fescue (r(2) = 0.99)] and DIA-WP and visual evaluations, respectively. Standard deviations within repeated measures were also calculated. A mixed-model ANOVA was used to determine differences (P < 0.05) in mean absolute error and mean standard deviation by method, disease range, and method by disease range. Disease ranged from 0 to 100%. Mean absolute error did not differ between methods but did by disease range, exhibiting a bell-shaped curve from 0% to 100% disease severity. Mean standard deviation exhibited significant method by disease range interaction. Mean standard deviation did not differ across the disease range within DIA-WP evaluations but did across the disease range within visual evaluations. The more consistent precision of DIA across the disease range could reduce variability in brown patch evaluations of tall fescue. Public domain – authored by a U.S. government employee

Divoting is a common occurrence on golf courses and athletic fields. Research was conducted at the University of Tennessee Center for Athletic Field Safety (Knoxville, TN) during 2012–13 evaluating the effects of preemergence (PRE) herbicide applications on hybrid bermudagrass [C. dactylon (L.) Pers. × C. transvaalensis Burtt-Davy, cv. Tifway] divot resistance and recovery. Plots were subjected to the factorial combination of seven herbicide treatments (indaziflam at 35 and 52.5 g·ha−1; prodiamine at 840 g·ha−1; pendimethalin at 3360 g·ha−1; dithiopyr at 560 g·ha−1; oxadiazon at 3360 g·ha−1; non-treated control) and three divot timings [1, 2, and 3 months after herbicide treatment (MAT)]. Rates were based on label recommendations for preemergence crabgrass (Digitaria spp.) control. Herbicides were applied on 15 Mar. 2012 and 2013. Divots were generated using a weighted pendulum apparatus designed to impart 531 J of impact energy to the turf sward with a golf club. Divot resistance was quantified by measuring divot volume at each timing while divot recovery was quantified by measuring turf cover in the divot scar using digital image analysis. All herbicide-treated plots produced divots with volumes ≤ the non-treated control. In 2013, volumes were greater for divots produced 1 MAT (215 cm3) than those created 2 MAT (191 cm3) or 3 MAT (157 cm3). No differences in divot recovery were detected as a result of herbicide treatment in either year. Under the conditions of this study, applications of PRE herbicides at labeled rates did not affect divot resistance or recovery.Chemical names: N-[(1R,2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1-yl]-6-(1-fluoroethyl)-1,3,5-triazine-2,4-diamine (indaziflam), 2,4 dinitro-N3,N3-dipropyl-6-(trifluoromethyl)-1,3-benzenediamine (prodiamine), N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin), S,S-dimethyl 2-(difluoromethyl)-4-(2-methylpropyl)-6-(trifluoromethyl)-3,5-pyridinedicarbothioate (dithiopyr), 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3H)-one (oxadiazon)

Different Rhizoctonia species and anastomosis groups (AGs) have been reported to show variable sensitivity to commercial fungicides. Thirty-six isolates of Rhizoctonia collected from turfgrasses were tested in vitro for sensitivity to commercial formulations of iprodione, triticonazole, and pyraclostrobin. Tested isolates represented R. solani AG 1-IB and AG 2-2IIIB; W. circinata varieties zeae (Wcz) and circinata (Wcc); and binucleate Rhizoctonia-like fungi (BNR) from different locations in Virginia and Maryland. Each fungicide was added to PDA medium to obtain concentrations at 0, 0.1, 1, 10 and 100 mg a.i.·L−1 (0.00001, 0.0001, 0.001 and 0.01 oz a.i.·gal−1). A mycelium plug from each isolate was grown on these plates. The fungicide concentration needed for 50% inhibition of radial growth (EC50) was determined for each isolate by fungicide combination. Waitea circinata isolates were moderately sensitive (EC50 = 1 to 10 mg a.i.·L−1) (0.0001 to 0.001 oz a.i.·gal−1) to iprodione while isolates of R. solani and BNR were extremely sensitive (EC50 < 1 mg a.i.·L−1). Isolates of AG 2-2IIIB exhibited less sensitivity to triticonazole (mean EC50 = 1.26 mg a.i.·L−1) than AG 1-IB and W. circinata (mean EC50 = 0.2, and 0.06 mg a.i.·L−1, respectively). BNR isolates varied in inhibition of growth by triticonazole, exhibiting extreme to moderate sensitivity. Isolates of W. circinata were moderately sensitive to pyraclostrobin while most cultures of R. solani and BNR were extremely sensitive. Geographic origin of isolates had no influence on the level of fungicide sensitivity. This study demonstrates the importance of accurately identifying the Rhizoctonia pathogen causing disease symptoms on a turfgrass for choosing an effective fungicide.

Tall fescue is a commonly used turfgrass in the temperate and transition zone areas of the United States. During hot, humid summers, tall fescue is under stress and is susceptible to Rhizoctonia solani (brown patch) infection, causing turf thinning, leading to encroachment from weeds, such as bermudagrass. Field trials were established to evaluate the effect of mowing height and fertility programs on disease severity and bermudagrass encroachment in tall fescue. Mowing at 10 cm resulted in less bermudagrass encroachment than did a 6-cm mowing height. Increasing the nitrogen fertilization level from 49 to 171 and 220 kg N ha−1 generally led to more bermudagrass encroachment at the 6-cm, but not the 10-cm, mowing height. Plots receiving 220 kg N ha−1 annually at the 6-cm mowing height had the most brown patch. Turfgrass cover was greatest in plots mowed at 10 cm and receiving 220 kg N ha−1 annually. Nomenclature: Bermudagrass; Cynodon dactylon (L.) Pers.; brown patch; Rhizoctonia solani Kuhn; tall ...

Field research was conducted in 2010 and 2011 to investigate the efficacy of herbicides for dallisgrass control when applied at various growing (GDD) or cooling degree day (CDD) –based application timings. Herbicide treatments included fluazifop-p-butyl (fluazifop; 105 g ai ha−1), mesotrione (280 g ai ha−1), tembotrione (92 g ai ha−1), topramezone (37 g ai ha−1), and tank mixtures of fluazifop plus mesotrione, tembotrione, or topramezone. Herbicide treatments were applied at either 75, 175, 375, 775 GDD, or 5 CDD. Treated plots were subjected to three tall fescue interseeding regimes: no seeding, seeding in spring, or seeding in fall (0, 353, and 353 kg pure live seed ha−1, respectively). In 2010, dallisgrass control from fluazifop applied at 75, 375, and 775 GDD was poor (< 50%) by 52 wk after treatment (WAT); in 2011, control from fluazifop application at these timings was higher (62 to 72%). When applied at 175 GDD or 5 CDD in 2010 and 2011, dallisgrass control from fluazifop ranged from 79 to 93% at 52 WAT. The addition of mesotrione, tembotrione, or topramezone to fluazifop did not affect dallisgrass control at any application timing, and control provided by these herbicides alone was low (< 65%). Interseeding tall fescue in the fall improved dallisgrass control from herbicides applied at 75 GDD in 2010 and 175, 375, and 775 GDD at 52 WAT in both years. Results suggest that timing of fluazifop applications at 175 GDD and 5 CDD enhances dallisgrass control.

Tall fescue (Festuca arundinacea) and hybrid bluegrass (Poa pratensis L. × Poa arachnifera) can both be successfully grown in the transition zone of the United States. However, each grass has limitations. Tall fescue is susceptible to the fungal pathogen Rhizoctonia solani, whereas slow establishment and susceptibility to weed infestations limit hybrid bluegrass. Previous studies have shown the benefits of combining kentucky bluegrass with tall fescue in seeding mixtures. Research was conducted to evaluate the impact of two seeding combinations of hybrid bluegrass and tall fescue (one combination seeded at a 1.9:1 seed count ratio favoring tall fescue, the other combination seeded at a 1:1.8 seed count ratio favoring hybrid bluegrass) as well as monocultures of the species on turfgrass cover, weed species infestation, brown patch disease severity caused by R. solani, sod strength and species ecology. The seeding combinations had lower weed density during establishment and greater turf cover than the monoculture of hybrid bluegrass. The monoculture of tall fescue was subjected to more brown patch disease than the seeding combinations during and after the first year of establishment. Brown patch infestations likely reduced tall fescue cover and led to a species shift favoring hybrid bluegrass in the seeding combinations based on tiller count and weight data. Seeding combinations of tall fescue and hybrid bluegrass are beneficial from an epidemiological perspective because they reduce disease and weed infestations compared with monocultures of either species. From an agronomic perspective, the seeding combination favoring tall fescue provided the densest turf, whereas the seeding combination favoring hybrid had the greatest sod strength. Chemical name used: clopyralid (3,6 dichloropyridine-2 carboxylic acid)

Annual bluegrass (Poa annua L.) is a problematic weed in tall fescue [Festuca arundinacea (Schreb.) S.J. Darbyshire], with limited options available for postemergence control. Field research was conducted to evaluate bispyribac-sodium application rates (37 or 74 g ai·ha−1) (0.033 or 0.066 lb ai·A−1) and timings (March, April or May) as well as iron supplementation on brown patch (Rhizoctonia solani) severity, annual bluegrass control, and tall fescue quality. In general, applying bispyribac-sodium to tall fescue did not result in significantly more brown patch than in untreated plots in field trials. Applying bispyribac-sodium in March or April resulted in significantly higher annual bluegrass control than applications in May. In greenhouse experiments, bispyribac-sodium at 37 and 74 g ai·ha−1 (0.033 or 0.066 lb ai·A−1) was applied to brown patch-inoculated tall fescue plants. Under conditions of high inoculum and humidity in those greenhouse studies, applications of bispyribac-sodium increased the number of brown patch lesions relative to untreated plants. Tall fescue plant height was initially reduced after being treated with bispyribac-sodium; however, six weeks after application tall fescue plants in treated with herbicide were taller than the nontreated plants.

Nitrogen fertilization of turfgrass continues to be scrutinized due to environmental concerns. Practices that reduce fertilizer inputs without sacrifi cing turfgrass quality are needed, but a reliable test of N status in turfgrass is not currently available. The Illinois soil N test has been developed to predict crop response to applied N by measuring the amount of amino sugar N in the soil. Amino sugar N does not fl uctuate as rapidly as other forms of N in soil. Our objective is to determine the spatial variation of amino sugar N in soil to determine sampling frequency requirements for use of the Illinois soil N test as a management tool on golf course fairways. Soil samples from 0 to 15, 15 to 30, and 30 to 45 cm were collected from golf course fairways in Minnesota and analyzed for amino sugar N concentration. Our data indicate that amino sugar N concentration decreases with depth but is not correlated to the concentration in the 0 to 15 cm layer. Amino sugar N concentrations measured on the four sampled fairways varied, but the spatial correlation present would allow for traditional soil sampling techniques to be used to assess the soil amino sugar N concentration within an area such as a golf course fairway. D.S. Gardner, Dep. of Horticulture and Crop Science, 2021 Coff

Dollar spot (Sclerotinia homoeocarpa F.T. Ben- nett) causes one of the most important diseases faced by golf course superintendents through- out the USA. Fungicides are effective, but fun- gicide resistance and regulation have restricted their use. Site-specifi c application allows more judicious use of fungicides, but the spatial het- erogeneity of dollar spot incidence has been unknown. An intensive study was designed to determine the spatial distribution of dollar spot incidence using geostatistical analysis. Dollar spot foci were manually counted every 2 to 3 d in 200 quadrats in 2000, and in 888 quadrats in 2001 and 2002. Variograms showed spatial aggregation of dollar spot foci on a small scale, and remained stable throughout the growing season despite increasing disease incidence. The range parameter of the variograms was stable within a season, with values ranging between 2.5 and 9.5, 1.3 and 1.9, and 1.2 and 2.2 m in 2000, 2001, and 2002, respectively. Kriged maps of dollar spot incidence also show a stable pattern of spatial aggregation remains throughout the growing season. The locations of dollar spot clusters changed between sea- sons, but the variograms from each season were similar, further suggesting stability of the spatial structure. It appears that limited second- ary dispersal of S. homoeocarpa occurs during epidemics, as evidenced by the stable vario- grams observed throughout the three growing seasons. The underlying factors involved in the observed stability are unknown.

A rapid identification assay for Waitea circinata (anamorph: Rhizoctonia spp.) varieties zeae and circinata causing patch diseases on turfgrasses was developed based on the universally primed PCR (UP- PCR) products cross-blot hybridization. Tester isolates belonging to the two varieties of W. circinata were amplified with a single UP primer L21, which generated multiple DNA fragments for each variety. Probes were prepared with UP-PCR products of each tester isolate by labeling with digoxigenin. Field- collected W. circinata isolates and representative isolates of different R. solani anastomosis groups (AG) and AG subgroups were amplified with L21, immobilized on nylon membrane and cross hybrid- ized with the two probes. Isolates within a W. circinata variety cross-hybridized strongly, while non-homolo- gous isolates did not cross-hybridize or did so weakly. Closely related W. circinata varieties zeae and circinata were clearly distinguished with this assay. Sequence- characterized amplified region (SCAR) markers also were developed from UP-PCR products to identify isolates of Thanatephorus cucumeris (anamorph: R. solani) AG 1-IB and AG 2-2IIIB. These two AGs are commonly isolated from diseased, cool-season turf- grasses. The specific SCAR markers that were devel- oped could differentiate isolates of AG 1-IB or AG 2- 2IIIB groups. These SCAR markers did not amplify a product from genomic DNA of nontarget isolates of Rhizoctonia. The specificities and sensitivities of the SCAR primers were tested on total DNA extracted from several field-grown, cool-season turf species having severe brown-patch symptoms. First, the leaf samples from diseased turf species were tested for the anastomosis groups of the causal pathogen, and thereafter the total DNA was amplified with the specific primers. The specific primers were sensitive and unique enough to produce a band from total DNA of diseased turfgrasses infected with either AG 1-IB or AG 2-2IIIB.

Rhizoctonia blight is a common and serious disease of many turfgrass species. The most widespread causal agent, Thanatephorus cucumeris (anamorph: R. solani), consists of several genetically different subpopulations. In addition, Waitea circinata varieties zeae, oryzae and circinata (anamorph: Rhizoctonia spp.) also can cause the disease. Accurate identification of the causal pathogen is important for effective management of the disease. It is challenging to distinguish the specific causal pathogen based on disease symptoms or macroscopic and microscopic morphology. Traditional methods such as anastomosis reactions with tester isolates are time consuming and sometimes difficult to interpret. In the present study universally primed PCR (UP-PCR) fingerprinting was used to assess genetic diversity of Rhizoctonia spp. infecting turfgrasses. Eighty-four Rhizoctonia isolates were sampled from diseased turfgrass leaves from seven distinct geographic areas in Virginia and Maryland. Rhizoctonia isolates were characterized by ribosomal DNA internal transcribed spacer (rDNA-ITS) region and UP-PCR. The isolates formed seven clusters based on ITS sequences analysis and unweighted pair group method with arithmetic mean (UPGMA) clustering of UP-PCR markers, which corresponded well with anastomosis groups (AGs) of the isolates. Isolates of R. solani AG 1-IB (n = 18), AG 2-2IIIB (n = 30) and AG 5 (n = 1) clustered separately. Waitea circinata var. zeae (n = 9) and var. circinata (n = 4) grouped separately. A cluster of six isolates of Waitea (UWC) did not fall into any known Waitea variety. The binucleate Rhizoctonia-like fungi (BNR) (n = 16) clustered into two groups. Rhizoctonia solani AG 2-2IIIB was the most dominant pathogen in this study, followed by AG 1-IB. There was no relationship between the geographic origin of the isolates and clustering of isolates based on the genetic associations. To our knowledge this is the first time UP-PCR was used to characterize Rhizoctonia, Waitea and Ceratobasidium isolates to their infra-species level.

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.