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

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.

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

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.

Cambios en las variables fisiológicas en equinos compitiendo en una prueba combinada / Changes in physiological variables in horses competing in a combined test

La frecuencia cardiaca (Fc), frecuencia respiratoria (Fr), temperatura rectal (Tr), glucosa (Gl), lactatoplasmático (Lp), hematocrito (Hto), proteínas totales (Pt), albúmina (Al), urea (U), creatinina (Cr), aspartatoaminotransferasa (AST), creatinquinasa (CK), lactato dehidrogenasa (LDH), gamaglutamiltransferasa (GGT),fosfatasa alcalina (FA), calcio (Ca) y fósforo (P) en un grupo de equinos, se estudiaron en reposo (R), a los 5minutos (T5), 30 minutos (T30) y 60 minutos (T60) de finalizada una Prueba Combinada, consistente en unafase de 8 saltos variados en pista de arena, con una distancia de 240 metros, a una velocidad de 400 metros porminuto (m/m) y un recorrido de exterior, con 15 obstáculos, con una distancia de 3.100 metros, a una velocidadde 690 m/m. La competición se desarrolló en el mes de mayo con una temperatura ambiente de 14° C y unahumedad del 88 %. Todos los parámetros se elevaron a T5, recuperándose a T30, excepto Fr y Lp, los que semantuvieron elevados a T30 y T60 por la acidosis metabólica propia de este tipo de ejercicio. La Gl se mantuvosin cambios a los distintos tiempos y el Ca descendió a T30. En las condiciones de esta Prueba Combinada,las variables medidas volvieron a valores fisiológicos en los tiempos considerados aceptables para caballos enbuen estado de entrenamiento, sin embargo, estas variables presentaron diferencias significativas (p<0.05) conlos valores de reposo

Heart rate, respiratory rate, rectal temperature, glucose, plasma lactate, pack cell volume, total proteins,albumin, urea, creatinine, aspartate aminotransferase, creatine kinase, lactate dehydrogenase, gamma glutamyltransferase, alkaline fosfatase, calcium and phosphorus, in a group of horses, were studied at rest, at five, thirty and sixty minutes from the end of a Combined Test, beginning with eight jumps in a sand ring, on a distance of240 meters, at a speed of 400 meters per minute and a cross country course with fifteen jumps, on a distance of3.100 meters, at a speed of 690 meters per minute. The event took place in May (Southern Hemisphere) with atemperature of 14° C and 88 % of humidity.All variables were elevated at five minutes, recovering at thirty minutes, except from respiratory rate andplasma lactate, both of witch remained elevate at thirty and sixty minutes, due to the metabolic acidosis, characteristicof this type of exercise.Glucose showed no changes at any time and calcium descended at thirty minutes.In the conditions of this Combined Test, all the variables measured in this experience, returned to physiologicalvalues at times considered acceptable for well trained horses, although there were significant differences(p<0.05) with rest values

Effects of Timing of Ethofumesate Application on Severity of Gray Leaf Spot of Perennial Ryegrass Turf.

Ethofumesate is a widely used herbicide for control of annual bluegrass (Poa annua) in perennial ryegrass (Lolium perenne) fairways on golf courses in the United States. Effect of timing of ethofumesate application on development of gray leaf spot was evaluated on perennial ryegrass turf treated with six classes of fungicide. Two applications of ethofumesate (2.28 kg a.i./ha) were made to perennial ryegrass turf maintained at a 2-cm height, at 4-week intervals, each fall (October and November 1999 and 2000) or spring (April and May 2000 and 2001). In addition, turf was treated with the fungicides, azoxystrobin, chlorothalonil, flutolanil, iprodione, propiconazole, or thiophanate-methyl at the label rates at 14-day intervals. There were significant effects (P ≤ 0.05) of ethofumesate application timing and fungicide regime on gray leaf spot development. There also were significant interactions between the ethofumesate application timing and fungicide. Severity of gray leaf spot was significantly greater in turf plots treated with ethofumesate in spring compared to turf treated in fall or nontreated control plots treated with fungicides, flutolanil, iprodione, and propiconazole that were relatively less effective in control of gray leaf spot. There was no significant difference in disease severity in turf treated with ethofumesate in fall or to turf not treated with herbicide regardless of the fungicide used. Results of this study indicate that spring application of ethofumesate contributes to development of gray leaf spot epidemics, and the application timing interacts with the classes of fungicides. This study suggests that ethofumesate should be applied only in fall for control of P. annua, particularly in golf courses with a chronic gray leaf spot problem, as part of an integrated management of gray leaf spot in perennial ryegrass fairways.

Influence of charged groups on the conformational stability of succinoglycan in dilute aqueous solution.

Viscosity, optical activity, and differential scanning calorimetry data clearly point out that partial and/or total removal of charged substituent groups, i.e. succinate and pyruvyl residues, from succinoglycan lead to water soluble derivatives exhibiting a higher stability order----disorder conformational changes with respect to the native polysaccharide. The new succinoglycan derivatives also exhibit very little, if any, hysteresis upon 'renaturation' (cooling) as opposed to the case of the parent polymer. The absence of ionized groups is thus beneficial, thermodynamically and kinetically, to the attainment in dilute aqueous solution of an ordered conformation by the uncharged succinoglycan backbone, as allowed by the regular enchainment of its constituent sugar residues.