Diagnosis of Trichodorus obtusus and Paratrichodorus minor on Turfgrasses in the Southeastern United States

2005 ◽  
Vol 6 (1) ◽  
pp. 20 ◽  
Author(s):  
William T. Crow
Keyword(s):  
United States ◽  
Plant Pathogens ◽  
Southeastern United States ◽  
Warm Season ◽  
Plant Viruses ◽  
Stubby Root Nematode

“Stubby-root” nematodes are of agricultural importance as plant-pathogens and as vectors for plant viruses. Two species of stubby-root nematode have been identified as pathogens on warm-season turfgrasses in the southern U.S.: Paratrichodorus minor and Trichodorus obtusus. Both are pathogens of bermudagrass and St. Augustinegrass, with T. obtusus more damaging than P. minor. Methods for distinguishing these species are described that do not require mounting of specimens and can be used at ×100 magnification or less. Accepted for publication 24 November 2004. Published 21 January 2005.

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.

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

scholarly journals First Report of Gaeumannomyces graminis var. graminis on Seashore Paspalum in the United States

Plant Disease ◽  
2002 ◽  
Vol 86 (12) ◽  
pp. 1405-1405 ◽  
Author(s):  
W. C. Elmore ◽  
M. D. Gooch ◽  
C. M. Stiles
Keyword(s):  
United States ◽  
Plant Pathogens ◽  
Warm Season ◽  
The United States ◽  
Gaeumannomyces Graminis ◽  
Sterile Soil ◽  
Seashore Paspalum ◽  
First Report ◽  
Fungal Plant Pathogens ◽  
Rot Disease

Gaeumannomyces graminis var. graminis is an ectotrophic, root-infecting fungus found on some warm-season turfgrass species (1). A sample of seashore paspalum (Paspalum vaginatum) exhibiting rotted roots and stolons was taken from dying patches of turf in a home lawn in Hernando County, FL, and submitted to the Florida Extension Plant Disease Clinic, Gainesville, in October 2001. The lawn had been established within the previous year. Strongly lobed hyphopodia typical of G. graminis var. graminis (3,4) were present on diseased roots and stolons, and no other fungal plant pathogens were detected in the sample. Diseased roots and stolons with lobed hyphopodia were surface-sterilized and placed on one-quarter-strength potato dextrose agar (PDA) amended with rifampicin and streptomycin. One isolate produced structures characteristic of G. graminis var. graminis (3,4), including dark, strongly lobed hyphopodia, and perithecia and ascospores in PDA after incubation. The isolate (PDC 2965) was grown on a sterile ryegrass seed substrate at 25°C for 4 weeks to produce inoculum (2). The isolate was used to inoculate pots of ‘Sea Isle 1’ seashore paspalum grown in sterile soil from sprigs. An inoculum layer, 1 to 2 cm deep, was placed 2 to 4 cm below each sprig and covered with an overlay of sterile soil prior to sprigging (2). Following 4 weeks of plant growth in a greenhouse, dark, necrotic lesions appeared on leaf bases. Very dark lesions developed on roots, and brown runner hyphae and strongly lobed hyphopodia were observed on root and shoot tissues. Selected pieces of symptomatic root and shoot tissue were surface-sterilized and placed on PDA. One week later, dark mycelia and deeply lobed hyphopodia were observed growing from roots and shoots on the PDA. After 1 month, black, flask-shaped perithecia, 156 to 234 μm in body width, developed in cultures. Hyaline, filiform, septate ascospores ranged from 75 to 100 μm (mean = 89 μm; n = 250) long and were approximately 2.5 μm wide. Hyphopodia, perithecia, and ascospores were characteristic of G. graminis var. graminis (3,4). To our knowledge, this is the first report of take-all root rot disease due to G. graminis var. graminis on seashore paspalum in the United States. References: (1) L. E. Datnoff et al. Plant Dis. 81:1127, 1997. (2) M. L. Elliott. Plant Dis. 79:699, 1995. (3) M. L. Elliott and P. J. Landschoot. Plant Dis. 75:238, 1991. (4) P. J. Landschoot. Taxonomy and biology of ectotrophic root-infecting fungi associated with patch diseases of turfgrasses. Pages 41–71 in: Turfgrass Patch Diseases. B. B. Clarke and A. B. Gould, eds. American Phytopathological Society, St. Paul, MN, 1997.

scholarly journals Winter grazing stockpiled native warm‐season grasses in the Southeastern United States

2018 ◽  
Author(s):  
Neal R. Wepking ◽  
Renata L. G. Nave ◽  
J. Travis Mulliniks ◽  
Zachary D. McFarlane
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Warm Season ◽  
Winter Grazing ◽  
Warm Season Grasses

Tolerance of pintoi peanut to PRE and POST herbicides

2020 ◽  
Vol 34 (6) ◽  
pp. 870-875
Author(s):  
Logan J. Martin ◽  
José Luiz C.S. Dias ◽  
Brent A. Sellers ◽  
Jason A. Ferrell ◽  
Ramon G. Leon ◽  
...  
Keyword(s):  
United States ◽  
Weed Management ◽  
Southeastern United States ◽  
Warm Season ◽  
Future Research ◽  
Herbicide Application ◽  
Forage Crop ◽  
Herbicide Treatments ◽  
Perennial Legume ◽  
Significant Injury

AbstractPintoi peanut is a warm-season perennial legume that shows promise as a forage crop for the southeastern United States, however, little is known about the proper methods of weed management during establishment for this species. The objective of this study was to determine the ability of pintoi peanut to tolerate applications of PRE and POST herbicides during the year of and year after planting. The effects of herbicide treatments on percentage of visual estimates of injury and stand counts of pintoi peanut were investigated at Ona and Marianna, FL, in 2015 and 2016. All PRE herbicides did not result in significant injury or stand reduction. Pintoi peanut’s tolerance to POST herbicides was higher when plants were emerged for at least 2 wk prior to herbicide application. Stands of pintoi peanut that were planted the previous year appear to tolerate all herbicides examined in this work, except sulfosulfuron. Results of this study indicate that at the year of planting pintoi peanut is tolerant to PRE applications of pendimethalin, imazethapyr, and imazapic. Pintoi peanut appears to tolerate applications of 2,4-D, carfentrazone, imazapic and imazethapyr the year after planting at the rates utilized in this study. Future research should evaluate the effects of multiple herbicide applications and tank-mixes to obtain satisfactory weed control and selectivity in pintoi peanut swards.

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.

scholarly journals Warm Season Mesoscale Superensemble Precipitation Forecasts in the Southeastern United States

2007 ◽  
Vol 22 (4) ◽  
pp. 873-886 ◽  
Author(s):  
T. J. Cartwright ◽  
T. N. Krishnamurti
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Warm Season ◽  
Stage Iv ◽  
Time Of Day ◽  
Florida State University ◽  
State University ◽  
Synoptic Conditions ◽  
Subtropical Highs ◽  
Operational Models

Abstract With current computational limitations, the accuracy of high-resolution precipitation forecasts has limited temporal and spatial resolutions. However, with the recent development of the superensemble technique, the potential to improve precipitation forecasts at the regional resolution exists. The purpose of this study is to apply the superensemble technique to regional precipitation forecasts to generate more accurate forecasts pinpointing exact locations and intensities of strong precipitation systems. This study will determine the skill of a regional superensemble forecast out to 60 h by examining its equitable threat score and its false alarm ratio. The regional superensemble consists of 12–60-h daily quantitative precipitation forecasts from six models. Five are independent operational models, and one comes from the physically initialized Florida State University regional spectral model. The superensemble forecasts are verified during the summer 2003 season over the southeastern United States using merged River Forecast Center stage-IV radar–gauge and satellite analyses. Precipitation forecasts were skillful in outperforming the operational models at all model times. Precipitation results were stratified by time of day to allow detections of the diurnal cycle. As expected, warm season daytime precipitation is commonly forced by convection, which is difficult to accurately model. Major synoptic regimes, including subtropical highs, midlatitude troughs/fronts, and tropical cyclones, were examined to determine the skill of the superensemble under various synoptic conditions.

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