scholarly journals Infection, Survival, and Growth of Clavibacter nebraskensis on Crop, Weed, and Prairie Plant Species

Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 2108-2112 ◽  
Author(s):  
B. T. Webster ◽  
R. D. Curland ◽  
R. R. McNally ◽  
C. A. Ishimaru ◽  
D. K. Malvick
Keyword(s):  
United States ◽  
Plant Species ◽  
Bacterial Pathogen ◽  
Primary Source ◽  
The United States ◽  
Schizachyrium Scoparium ◽  
Grass Species ◽  
Leaf Sample ◽  
Maize Production ◽  
Little Bluestem

Clavibacter nebraskensis is the causal agent of Goss’s leaf blight and wilt, an important disease of maize in the United States and Canada. The epidemiology and ecology of this bacterial pathogen are poorly understood. Infested maize residue is often considered to be the primary source of inoculum for maize; however, the potential for many other plant species to be infected and serve as inoculum sources is unknown. The goal of this study was to determine if C. nebraskensis could infect, survive, and grow on common weed, crop, and grass species. Seedling leaves of 18 plant species that grow in maize production areas in the United States were inoculated with this pathogen in a controlled environment and in the field. Lesion development, bacterial streaming, and pathogen population size on leaves were then determined and used as criteria to evaluate host–pathogen interactions. Woolly cupgrass (Eriochloa villosa) and the native prairie grasses big bluestem (Andropogon gerardii) and little bluestem (Schizachyrium scoparium) developed lesions and bacterial streaming, identifying them as hosts and susceptible to infection. To our knowledge, this is the first report of these grass species being hosts of C. nebraskensis. Ten other grass species, including wheat and oats, were identified as potential sustaining hosts that maintained epiphytic or endophytic pathogen populations >106 colony forming units per leaf sample but displayed no evidence of infection. Five broadleaf species tested were nonhosts based on the three criteria. This study suggests that multiple plant species support infection and growth of C. nebraskensis and further elucidates the ecology of this pathogen and the epidemiology of Goss’s wilt.

scholarly journals Uso y manejo de Ibervillea millspaughii (Cogn.) C. Jeffrey, Melothria pendula L. y otras especies silvestres de la familia Cucurbitacea: Posibles procesos de domesticación incipiente

2017 ◽  
pp. 77
Author(s):  
Rafael Lira ◽  
Alejandro Casas
Keyword(s):  
United States ◽  
Traditional Medicine ◽  
Plant Species ◽  
Wild Species ◽  
The United States ◽  
Plant Domestication ◽  
Wild Populations ◽  
Perennial Plant ◽  
Muscular Pain ◽  
Stems And Leaves

Information on use and management of wild species of Cucurbitaceae is presented, in order to analyze processes of incipient plant domestication. Ibervillea millspaughii is a perennial plant species with massive roots, distributed from Tamaulipas to Belize. Roots of this species are utilized as medicine in the treatment of arthritis, inflammations and muscular pain. Roots are commonly collected from individuals in wild populations, but, in some villages of Quinatana Roo people tolerate and enhance individuals of this plant species in anthropogenic areas; also, people cultivate this plant species in home gardens. Melothria pendula is distributed from the United States to Argentina. Fruits and young stems and leaves of this species are consumed as food and used in traditional medicine. These products are generally gathered from wild or weedy populations, but in La Montaña de Guerrero region, the tolerance of this species and the intentional dispersion of its seeds in anthropogenic areas are also common, in order to increase its availability. Use and propagation of this plant species may involve selection by people who distinguish between "bitter" and "sweet" variants, preferring the "sweet" ones. Sicyos parviflorus, Cyclanthera dissecta, C. langaei and C. ribiflora are consumed as greens by people in different regions of Mexico, who gather them from wild or weedy populations, although individual plants of these species are also tolerated in anthropogenic areas. The different forms of management identified in the species mentioned are possibly causing processes of domestication, but such processes are yet to be evaluated.

scholarly journals Alternanthera mosaic virus Found in Scutellaria, Crossandra, and Portulaca spp. in Florida

Plant Disease ◽  
2006 ◽  
Vol 90 (6) ◽  
pp. 833-833 ◽  
Author(s):  
C. A. Baker ◽  
L. Breman ◽  
L. Jones
Keyword(s):  
Electron Microscopy ◽  
United States ◽  
Mosaic Virus ◽  
Plant Species ◽  
The United States ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rt Pcr ◽  
Indicator Plants ◽  
Partial Identity ◽  
Pcr Products

In the fall of 1998, the Division of Plant Industry (DPI) received vegetative propagations of Scutellaria longifolia (skullcap) with symptoms of foliar mosaic, chlorotic/necrotic ringspots, and wavy line patterns from a nursery in Manatee County. Flexuous particles approximately 500 nm long were found with electron microscopy. The plants tested positive for Papaya mosaic virus (PaMV) in an enzyme-linked immunosorbent assay (ELISA) test with antiserum to PaMV (Agdia, Elkhart, IN). However, in immunodiffusion tests (antiserum from D. Purcifull, University of Florida), this virus gave a reaction of partial identity indicating it was related but not identical to PaMV (1). The original infected plants were kept in a greenhouse. In January 2005, a specimen of Crossandra infundibuliformis (firecracker plant) with mosaic symptoms was submitted to the DPI from a nursery in Alachua County. Inclusions found with light microscopy and particles found with electron microscopy indicated that this plant was infected with a potexvirus. This was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) with primers designed to detect members of the virus family Potexviridae (3). These plants reacted positive to PaMV antiserum in ELISA and gave a reaction of partial identity to PaMV in immunodiffusion. A specimen of Portulaca grandiflora (moss rose) with distorted leaves found at a local retail store was also tested and gave the same results. Leaves from each of the three plant species were rubbed onto a set of indicator plants using Carborundum and potassium phosphate buffer. Total RNA was extracted from symptomatic indicator plants of Nicotiana benthamiana. RT-PCR (3) was performed, and PCR products were sequenced directly. Sequences of approximately 700 bp were obtained for all three plant species and showed 98% identity with each other. BLAST search results showed that these sequences were 93% identical to an Alternanthera mosaic virus (AltMV) sequence at the nucleotide level but only 76% identical to PaMV. The amino acid sequences were 98 and 82% identical to AltMV and PaMV, respectively. The PCR products of the virus from Scutellaria sp. were cloned, resequenced, and the sequence was entered into the GenBank (Accession No. DQ393785). The bioassay results matched those found for AltMV in Australia (2) and the northeastern United States (4), except that the Florida viruses infected Datura stramonium and Digitalis purpurea (foxglove). The virus associated with the symptoms of these three plants appears to be AltMV and not PaMV. AltMV has been found in ornamental plants in Australia, Italy, and the United States (Pennsylvania, Maryland, and now Florida). Since this virus is known to infect several plants asymptomatically and can be easily confused with PaMV serologically, it is likely that the distribution of this virus is much wider than is known at this time. References: (1) L. L. Breman. Plant Pathology Circular No. 396. Fla. Dept. Agric. Consum. Serv. DPI, 1999. (2) A. D. W. Geering and J. E. Thomas. Arch Virol 144:577, 1999. (3) A. Gibbs et al. J Virol Methods 74:67, 1998. (4) J. Hammond et al. Arch Virol. 151:477, 2006.

A Comparative Study on Undergraduate Computer Science Education between China and the United States

2015 ◽  
pp. 918-933
Author(s):  
Eric P. Jiang
Keyword(s):  
United States ◽  
Science Education ◽  
Comparative Study ◽  
Computer Science ◽  
Computer Science Education ◽  
Primary Source ◽  
The United States ◽  
Education Systems ◽  
Public And Private ◽  
Computer Scientists

With the rapid growth of the Internet and telecommunication networks, computer technology has been a driving force in global economic development and in advancing many areas in science, engineering, health care, business, and finance that carry significant impacts on people and society. As a primary source for producing the workforce of software engineers, computer scientists and information technology specialists, computer science education plays a particularly important role in modern economic growth and it has been invested heavily in many countries around the world. This chapter provides a comparative study of undergraduate computer science programs between China and the United States. The study focuses on the current curricula of computer science programs. It in part is based on the author's direct observation from his recent visits to several universities in China and the conversations he had with administrators and faculty of computer science programs at the universities. It is also based on the author's over two decades experience as a computer science educator at several public and private American institutions of higher educations. The education systems in China and the United States have different features and each of the systems has its strengths and weaknesses. This is likely also true for education systems in other countries. It would be an interesting and important task for us to explore an innovative computer science education program, which perhaps blends the best features of different systems and helps better prepare graduates for the challenges working in an increasingly globalized world. We hope the study presented in this chapter provides some useful insights in this direction.

scholarly journals Alternative Hosts in the Families Poaceae and Cyperaceae for Xanthomonas vasicola pv. vasculorum, Causal Agent of Bacterial Leaf Streak of Corn

2020 ◽  
Vol 110 (6) ◽  
pp. 1147-1152 ◽  
Author(s):  
T. Hartman ◽  
B. Tharnish ◽  
J. Harbour ◽  
G. Y. Yuen ◽  
T. A. Jackson-Ziems
Keyword(s):  
United States ◽  
Festuca Arundinacea ◽  
Field Experiments ◽  
The United States ◽  
Phleum Pratense ◽  
Schizachyrium Scoparium ◽  
Big Bluestem ◽  
Bacterial Leaf Streak ◽  
Alternative Hosts ◽  
Palm Species

The bacterial pathogen Xanthomonas vasicola pv. vasculorum was first reported in the United States causing bacterial leaf streak on Nebraska corn (Zea mays) in 2016. The bacterium is also known to cause disease in sugarcane, grain sorghum, broom bamboo, and various palm species. The objective of this study was to identify alternative hosts for X. vasicola pv. vasculorum among plants commonly found in corn growing areas of the United States. In repeated greenhouse experiments, 53 species of plants found in the United States that had not been tested previously for susceptibility to X. vasicola pv. vasculorum were inoculated with the pathogen and monitored for symptom development. Eleven species in the family Poaceae exhibited symptoms: oat (Avena sativa), rice (Oryza sativa), orchardgrass (Dactylis glomerata), indiangrass (Sorghastrum nutans), big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), timothy (Phleum pratense), sand bluestem (Andropogon hallii), green foxtail (Setaria viridis), bristly foxtail (Setaria verticillata), and johnsongrass (Sorghum halepense). Yellow nutsedge (Cyperus esculentus) in the Cyperaceae also was a symptomatic host. In addition, endophytic colonization by X. vasicola pv. vasculorum was found in three asymptomatic alternative hosts: downy brome (Bromus tectorum), tall fescue (Festuca arundinacea), and western wheatgrass (Pascopyum smithii). Experiments were also conducted in the field to determine the potential for alternative hosts to become infected by natural inoculum. Symptoms developed only in big bluestem and bristly foxtail in field experiments. These results suggest that infection of alternative hosts by X. vasicola pv. vasculorum can occur, but infection rates might be limited by environmental conditions.

scholarly journals “Battle of the Extremes”: Party Polarization in the 2010 Pennsylvanian Senatorial Election

2011 ◽  
Vol 1 ◽  
pp. 21-31
Author(s):  
Emily Lieffers
Keyword(s):  
United States ◽  
American Politics ◽  
Primary Source ◽  
Political Engagement ◽  
The United States ◽  
Election Campaigns ◽  
Primary Election ◽  
Party Polarization ◽  
Secondary Sources ◽  
Depth Analysis

This paper provides an in-depth analysis of the senatorial election held in Pennsylvania in November of 2010. The paper outlines the state's primary election campaigns and the eventual campaign between two ideologically-opposed candidates, Sestak and Toomey. By referencing extensive primary source documents (interviews, campaign videos, and speeches), supported by scholarly secondary sources, this paper argues that Pennsylvania's senatorial election is emblematic of greater party polarization across the United States. The candidates' unwillingness to provide moderate solutions to appeal to voters in this swing state is noteworthy and is reflective of the decline of centrist politics in the country. Though narrow in scope, the argument put forth in this paper has broader implications for polarization and political engagement in contemporary American politics.

Patterns and Sources of Ticket Splitting in Subpresidential Voting

1992 ◽  
Vol 86 (4) ◽  
pp. 916-928 ◽  
Author(s):  
Paul Allen Beck ◽  
Lawrence Baum ◽  
Aage R. Clausen ◽  
Charles E. Smith
Keyword(s):  
United States ◽  
Primary Source ◽  
The United States ◽  
Individual Characteristics ◽  
Divided Government ◽  
Comprehensive Model ◽  
Research Traditions ◽  
Comprehensive Examination ◽  
New Type ◽  
The Individual

The primary source of divided government in the United States is voters who split their ballots between the parties. Yet there has been little comprehensive examination of either patterns or sources of ticket splitting in recent years. Instead, divergent lines of research have emerged, emphasizing such things as voter partisanship, incumbency, and a “new” (young, well-educated, even partisan) kind of ticket splitter; and their focus has been too often restricted to the atypical president–Congress pair. We seek to unify these research traditions in a comprehensive model of split-ticket voting and to test this model across the partisan ballot in a typical election setting-here, the contests for five Ohio state-wide offices in 1990. The model incorporates partisan strength, candidate visibility, and the individual characteristics that distinguish the “new ticket splitters”. The results support our partisan strength and candidate visibility explanations but provide little support for the emergence of a new type of ticket splitter.

La Campaña Permanente: Mexico's Antidrug Campaign

1978 ◽  
Vol 20 (2) ◽  
pp. 107-131 ◽  
Author(s):  
Richard B. Craig
Keyword(s):  
United States ◽  
Drug Abuse ◽  
Drug Use ◽  
South America ◽  
Primary Source ◽  
The United States ◽  
High Potency ◽  
Psychotropic Substances ◽  
Antidrug Campaign ◽  
The U.S

The problems associated with drug abuse in the United States have received considerable attention in recent years. By the mid-1970s, approximately 500,000 Americans were addicted to heroin, while at least 15 million were regular or casual users of marijuana. None of this heroin originates domestically, and only a small percentage of the marijuana, and this of low potency, is home-grown. Consequently, the question of source has become cardinal to most analyses of drug use and abuse in the United States.Mexico has long been the primary source of high potency marijuana for the American market. Despite the recent influx from Jamaica and Colombia, Mexico still supplies an estimated 70% of the annual American consumption, or some 10 million pounds. More importantly, Mexico is currently the source of 70% to 80% of the heroin on the U.S. market, an alarming 6-8 ton annual figure. Furthermore, Mexico is both a primary transshipment route for cocaine, an increasingly popular drug originating in South America, and the source of vast quantities of psychotropic substances.

A Worthwhile Effort? History of Organized Youth Sport in the United States

2013 ◽  
Vol 2 (1) ◽  
pp. 65-75 ◽  
Author(s):  
David K. Wiggins
Keyword(s):  
United States ◽  
Twentieth Century ◽  
Youth Sports ◽  
Primary Source ◽  
Youth Sport ◽  
The United States ◽  
Source Material ◽  
Educational Institutions ◽  
Sports Programs ◽  
History Of

This essay examines the evolution of highly organized youth sports in the United States. Through an examination of both secondary and primary source material, an analysis is made of children's participation in sport from the turn of the twentieth century to the present day. Particular attention is paid to the types of sports programs established for children as well as the various discussions involving the supposed benefits and negative aspects of youth sports. Included is information on Progressive Reformers, youth sport programs outside of educational institutions, and guidelines, reports, assessments, and scholarly evaluation of children and their involvement in sport.

scholarly journals Buried Treasure or Buried Hope? The Status of Mexico-U.S. Transboundary Aquifers under International Law

2011 ◽  
Vol 13 (3) ◽  
pp. 273-290 ◽  
Author(s):  
Gabriel E. Eckstein
Keyword(s):  
United States ◽  
International Law ◽  
Groundwater Resources ◽  
Primary Source ◽  
The United States ◽  
International Agreement ◽  
National Economic ◽  
The Status ◽  
Critical Resource ◽  
Transboundary Aquifers

AbstractTransboundary aquifers found along the 2,000 mile-long border between Mexico and the United States are not governed by any treaty. Yet, these aquifers are the primary source of water for many of the twelve million people who live in this parched region. The region’s groundwater, however, is being overexploited and contaminated, which is threatening the very life that it currently sustains. As populations continue to expand and current rates of haphazard development persist, the absence of an agreement for the management and allocation of this critical resource could lead to bi-national economic, social and environmental tragedies. This study reviews groundwater resources along the Mexico-United States border and considers the obstacles to the development of an international agreement. It also looks at existing sources of law at the local, regional, national, and international levels of governance. The article offers recommendations that may lead to an amicable arrangement between the two nations.

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