scholarly journals Frequency and Pathogenicity of Dematiaceous Hyphomycetes on Annual Ryegrass Overseeded on Bermudagrass in Mississippi

Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1085-1090 ◽  
Author(s):  
R. G. Pratt
Keyword(s):  
United States ◽  
North American ◽  
Fungal Pathogens ◽  
Cynodon Dactylon ◽  
Southeastern United States ◽  
Axenic Culture ◽  
Warm Season ◽  
Application Site ◽  
Annual Ryegrass ◽  
Dematiaceous Hyphomycetes

Fungal diseases of annual ryegrass (Lolium multiflorum Lam.), a cool-season species grown for forage and turf in the southeastern United States, and bermudagrass (Cynodon dactylon (L.) Pers.), a warm-season perennial, usually are considered distinct. In May 2002 and 2004, symptoms of leaf and stem necrosis were observed simultaneously in forage bermudagrass and overseeded annual ryegrass on a swine waste application site in Mississippi. Sporulation by nine species of Bipolaris, Curvularia, Drechslera, and Exserohilum was observed on symptomatic leaves of ryegrass that were surface disinfested and plated on agar each year, and axenic cultures were established by spore transfers. These isolations represent four new worldwide and two new North American records of occurrence of fungal pathogens on ryegrass, and three new records for the southeastern United States and Mississippi. Bipolaris cynodontis, a common bermudagrass pathogen, and Drechslera dictyoides were observed most frequently on ryegrass during both years. In excised leaves of ryegrass inoculated with infested agar discs, most isolates of B. cynodontis from ryegrass and bermudagrass were equally virulent and caused necrosis equal to or greater than that caused by D. dictyoides, an established ryegrass pathogen. Isolates of B. cynodontis from both hosts also caused similar symptoms in foliage of ryegrass and bermudagrass following spore inoculations. Pathogenicity to ryegrass of five other species of dematiaceous hyphomycetes that represented new worldwide or North American records of occurrence also was demonstrated by foliar inoculations. All pathogens were reisolated from symptomatic tissues and grown in axenic culture for fulfillment of Koch's postulates. Results demonstrate that most of the same species of dematiaceous hyphomycetes infect both forage ryegrass and bermudagrass in Mississippi and indicate that B. cynodontis, in particular, may be a common and virulent pathogen of ryegrass in the southeastern United States.

Breeding a heat‐tolerant annual ryegrass for earlier fall planting in the southeastern United States

Crop Science ◽  
2020 ◽  
Vol 60 (2) ◽  
pp. 830-840
Author(s):  
Eric D. Billman ◽  
Jesse I. Morrison ◽  
Brian S. Baldwin
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Annual Ryegrass ◽  
Heat Tolerant

scholarly journals Tilletia walkeri on Annual Ryegrass in Wheat Fields in the Southeastern United States

Plant Disease ◽  
1999 ◽  
Vol 83 (7) ◽  
pp. 685-689 ◽  
Author(s):  
Barry M. Cunfer ◽  
Lisa A. Castlebury
Keyword(s):  
United States ◽  
Lolium Multiflorum ◽  
Southeastern United States ◽  
Karnal Bunt ◽  
Annual Ryegrass ◽  
Wheat Seed ◽  
Tilletia Indica ◽  
Wheat Field ◽  
South Central ◽  
Low Levels

Surveys for Tilletia walkeri on annual ryegrass (Lolium multiflorum) were conducted during 1997 and 1998 in the southeastern United States, where suspect teliospores of the Karnal bunt fungus, Tilletia indica, were found in USDA-APHIS surveys of wheat (Triticum aestivum) seed in 1996. T. walkeri is morphologically similar to T. indica. Annual ryegrass is a common weed in wheat fields in the southeastern United States. Between April and June 1997, ryegrass seed samples were collected from 190 fields of wheat in 47 counties in Georgia and from 26 fields in 17 counties in Alabama and south-central Tennessee. In 1998, 70 samples were collected from 40 counties in the same regions of the three states. The teliospores from these samples were 23 to 45 μm in diameter (average about 33 μm) and ranged from light brown to dark reddish brown. They had coarse, widely spaced cerebriform ridges on the surface and were surrounded by a gelatinous sheath. The ryegrass bunt was identified as the recently described species T. walkeri, occurring on ryegrass seed from Australia and Oregon. In 1997, teliospores of T. walkeri were found in 13 samples from eight counties in central Georgia and from one field in Tennessee. In 1998, more teliospores and bunted seeds were found, possibly due to frequent rain in the region throughout the flowering period for ryegrass. Teliospores were found in 26/70 of the samples, and among these, only a small number of bunted seed were found in 12 of 13/70 samples. In one wheat field in Morgan County, Georgia, about 50% of the ryegrass seed collected was partially bunted, and a small percentage was completely bunted. Fields with teliospores were widely distributed and generally matched the locations where teliospores were found in APHIS wheat seed surveys in 1996 to 1998. T. walkeri occurs at very low levels on ryegrass in the Southeast and is the source of teliospores, initially identified as those of T. indica, associated with wheat seed in APHIS surveys. No bunted wheat seeds or teliospores of T. indica were found in the survey.

scholarly journals Climatology and Environmental Characteristics of Extreme Precipitation Events in the Southeastern United States

2015 ◽  
Vol 143 (3) ◽  
pp. 718-741 ◽  
Author(s):  
Benjamin J. Moore ◽  
Kelly M. Mahoney ◽  
Ellen M. Sukovich ◽  
Robert Cifelli ◽  
Thomas M. Hamill
Keyword(s):  
United States ◽  
Extreme Precipitation ◽  
Southeastern United States ◽  
Warm Season ◽  
Stage Iv ◽  
Flow Patterns ◽  
Water Vapor Transport ◽  
Cool Season ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract This paper documents the characteristics of extreme precipitation events (EPEs) in the southeastern United States (SEUS) during 2002–11. The EPEs are identified by applying an object-based method to 24-h precipitation analyses from the NCEP stage-IV dataset. It is found that EPEs affected the SEUS in all months and occurred most frequently in the western portion of the SEUS during the cool season and in the eastern portion during the warm season. The EPEs associated with tropical cyclones, although less common, tended to be larger in size, more intense, and longer lived than “nontropical” EPEs. Nontropical EPEs in the warm season, relative to those in the cool season, tended to be smaller in size and typically involved more moist, conditionally unstable conditions but weaker dynamical influences. Synoptic-scale composites are constructed for nontropical EPEs stratified by the magnitude of vertically integrated water vapor transport (IVT) to examine distinct scenarios for the occurrence of EPEs. The composite results indicate that “strong IVT” EPEs occur within high-amplitude flow patterns involving strong transport of moist, conditionally unstable air within the warm sector of a cyclone, whereas “weak IVT” EPEs occur within low-amplitude flow patterns featuring weak transport but very moist and conditionally unstable conditions. Finally, verification of deterministic precipitation forecasts from a reforecast dataset based on the NCEP Global Ensemble Forecast System reveals that weak-IVT EPEs were characteristically associated with lower forecast skill than strong-IVT EPEs. Based on these results, it is suggested that further research should be conducted to investigate the forecast challenges associated with EPEs in the SEUS.

scholarly journals Two new species of <i>Mennerotodus</i> Zhelezko, 1994 (Chondrichthyes: Lamniformes: Odontaspididae), from the Paleogene of the southeastern United States

Fossil Record ◽  
2020 ◽  
Vol 23 (2) ◽  
pp. 117-140
Author(s):  
David J. Cicimurri ◽  
Jun A. Ebersole ◽  
George Martin
Keyword(s):  
United States ◽  
New Species ◽  
North American ◽  
Middle Eocene ◽  
Southeastern United States ◽  
Single Species ◽  
The World ◽  
Two New Species ◽  
Early Paleocene

Abstract. Mennerotodus Zhelezko, 1994, is an extinct lamniform shark known to occur in Paleogene strata of the Tethyan region of Asia and Europe. Although only a single species has been named, multiple subspecies have been erected and used as biostratigraphic tools in Asia. The genus has not been reported with confidence outside of the Tethyan region, but we have identified two new species of Mennerotodus from Paleogene deposits of the southeastern United States. Mennerotodus mackayi sp. nov. is described by teeth occurring in the lower Paleocene (Danian Stage) Pine Barren Member of the Clayton Formation of southern Alabama. A middle Eocene (Bartonian) species, Mennerotodus parmleyi sp. nov., is based on material occurring in the Clinchfield Formation in central Georgia. The early Paleocene record could indicate a North American origin for Mennerotodus relatively soon after the K–Pg event, with subsequent radiation to other parts of the world. The genus is likely more widely distributed than is currently known, but teeth can easily be overlooked due to their similarity to other taxa.

scholarly journals “Peach and Nectarine Varieties”-A Hypertext Index

HortScience ◽  
1993 ◽  
Vol 28 (12) ◽  
pp. 1186-1187 ◽  
Author(s):  
W.R. Okie
Keyword(s):  
United States ◽  
Computer Program ◽  
North American ◽  
Southeastern United States ◽  
The United States ◽  
General Information ◽  
Breeding Programs

“Peach and Nectarine Varieties” is a self-contained computer program describing more than 600 varieties and their performance in the southeastern United States. The information can be accessed in various ways, including searching for any word or name. A Master Index of names and synonyms lists more than 6000 names used in the United States, plus many foreign names. This index includes pedigree, origin, and a coded description. General information is included regarding peaches and nectarines. All North American breeding programs are chronicled. The program is available for MS-DOS computers with an EGA or VGA monitor, and may be freely distributed.

Sulfometuron for Eliminating Bahiagrass (Paspalum notatum) From Centipedegrass (Eremochloa ophiuroides) and Bermudagrass (Cynodon dactylon)

1989 ◽  
Vol 3 (3) ◽  
pp. 509-512 ◽  
Author(s):  
Wayne W. Hanna ◽  
Charles W. Swann ◽  
Jill Schroeder ◽  
Phil R. Utley
Keyword(s):  
United States ◽  
Cynodon Dactylon ◽  
Southeastern United States ◽  
Paspalum Notatum ◽  
Coastal Bermudagrass ◽  
Eremochloa Ophiuroides

This study was conducted to determine if ‘Pensacola’ bahiagrass, a major weed in turf and pastures in the southeastern United States, could be eliminated selectively from centipedegrass and ‘Tifway’ bermudagrass turf and a ‘Coastal’ bermudagrass pasture by treating with sulfometuron. Established Pensacola bahiagrass usually was controlled satisfactorily in Tifway bermudagrass and centipedegrass turf and in a Coastal bermudagrass pasture with sulfometuron at 210, 160, 105 g ai/ha applied twice, respectively. Bahiagrass seedlings were eliminated from both newly planted centipedegrass and Tifway bermudagrass turf with 105 g/ha sulfometuron applied once.

scholarly journals Effects of Topramezone and Bispyribac-sodium in Irrigation Water on Warm-season Turfgrasses

2017 ◽  
Vol 27 (5) ◽  
pp. 599-606
Author(s):  
William T. Haller ◽  
Lyn A. Gettys ◽  
Taizo Uchida
Keyword(s):  
Weed Control ◽  
Cynodon Dactylon ◽  
Southeastern United States ◽  
Warm Season ◽  
Hydrilla Verticillata ◽  
Paspalum Notatum ◽  
Aquatic Weed ◽  
Primary Target ◽  
Low Concentrations ◽  
Herbicide Concentration

Topramezone and bispyribac-sodium were registered for aquatic weed control in the last decade. A primary target for these products is fluridone-resistant hydrilla (Hydrilla verticillata), which is one of the most invasive submersed weeds in the southeastern United States. Both products have water use restrictions that prohibit irrigation of turfgrasses with treated waters until the herbicides have degraded to very low concentrations. The objective of these studies was to identify the concentrations of topramezone and bispyribac-sodium that are phytotoxic to turfgrasses that are commonly planted in Florida. Three species of turfgrass were irrigated twice weekly with 0.5 inch of treated water for 4 weeks (eight irrigations total). Cumulative EC10 values (the herbicide concentration that caused a 10% reduction in biomass compared with untreated control plants) after eight irrigations with water containing topramezone were 3.5, 4.3, and 17 ppb for ‘Palmetto’ st. augustinegrass (Stenotaphrum secundatum), ‘Pensacola’ bahiagrass (Paspalum notatum), and ‘Tifway 419’ hybrid bermudagrass (Cynodon dactylon × C. transvaalensis), respectively. Bispyribac-sodium was less toxic to all turfgrasses evaluated, with EC10 values of 56, 16, and >800 ppb for ‘Palmetto’ st. augustinegrass, ‘Pensacola’ bahiagrass, and ‘Tifway 419’ hybrid bermudagrass, respectively. These results support label instructions and highlight the need to comply with irrigation restrictions because the typical use concentrations for submersed weed control with topramezone and bispyribac-sodium are in the 20–40-ppb range.

IPCC’s Twentieth-Century Climate Simulations: Varied Representations of North American Hydroclimate Variability

2006 ◽  
Vol 19 (16) ◽  
pp. 4041-4058 ◽  
Author(s):  
Alfredo Ruiz-Barradas ◽  
Sumant Nigam
Keyword(s):  
United States ◽  
Twentieth Century ◽  
North American ◽  
Warm Season ◽  
Precipitation Variability ◽  
Model Version ◽  
Central United States ◽  
Hydroclimate Variability ◽  
Moisture Fluxes ◽  
The U.S

Abstract The annual cycle of precipitation and the interannual variability of the North American hydroclimate during summer months are analyzed in coupled simulations of the twentieth-century climate. The state-of-the-art general circulation models, participating in the Fourth Assessment Report for the Intergovernmental Panel on Climate Change (IPCC), included in the present study are the U.S. Community Climate System Model version 3 (CCSM3), the Parallel Climate Model (PCM), the Goddard Institute for Space Studies model version EH (GISS-EH), and the Geophysical Fluid Dynamics Laboratory Coupled Model version 2.1 (GFDL-CM2.1); the Met Office’s Third Hadley Centre Coupled Ocean–Atmosphere GCM (UKMO-HadCM3); and the Japanese Model for Interdisciplinary Research on Climate version 3.2 [MIROC3.2(hires)]. Datasets with proven high quality such as NCEP’s North American Regional Reanalysis (NARR), and the Climate Prediction Center (CPC) U.S.–Mexico precipitation analysis are used as targets for simulations. Climatological precipitation is not easily simulated. While models capture winter precipitation very well over the U.S. northwest, they encounter failure over the U.S. southeast in the same season. Summer precipitation over the central United States and Mexico is also a great challenge for models, particularly the timing. In general the UKMO-HadCM3 is closest to the observations. The models’ potential in simulating interannual hydroclimate variability over North America during the warm season is varied and limited to the central United States. Models like PCM, and in particular UKMO-HadCM3, exhibit reasonably well the observed distribution and relative importance of remote and local contributions to precipitation variability over the region (i.e., convergence of remote moisture fluxes dominate over local evapotranspiration). However, in models like CCSM3 and GFDL-CM2.1 local contributions dominate over remote ones, in contrast with warm-season observations. In the other extreme are models like GISS-EH and MIROC3.2(hires) that prioritize the remote influence of moisture fluxes and neglect the local influence of land surface processes to the regional precipitation variability.

Curvularia malina sp. nov. incites a new disease of warm-season turfgrasses in the southeastern United States

Mycologia ◽  
2016 ◽  
Vol 108 (5) ◽  
pp. 915-924 ◽  
Author(s):  
Maria Tomaso-Peterson ◽  
Young-Ki Jo ◽  
Phillip L. Vines ◽  
Federico G. Hoffmann
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Warm Season ◽  
New Disease
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