15 results
Performance of Colletotrichum dematium for the Control of Fireweed (Epilobium angustifolium) Improved with Formulation
- Christian Léger, Steven G. Hallett, Alan K. Watson
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- Journal:
- Weed Technology / Volume 15 / Issue 3 / September 2001
- Published online by Cambridge University Press:
- 20 January 2017, pp. 437-446
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The potential of Colletotrichum dematium f.sp. epilobii (ATCC 20981) to control fireweed (Epilobium angustifolium) was investigated. Under controlled environment conditions, plant age, inoculum density, length of the dew period, and temperature during the dew period affected the efficacy of C. dematium f.sp. epilobii. Seedlings sprayed with 1 × 109 conidia/m2 sustained the most damage. Susceptibility decreased with increasing plant age, and 10-wk-old plants were slightly affected by the fungus. Satisfactory levels of control were achieved when the dew period was >20 h and temperature during the dew period was 30 C. Control of fireweed increased when the C. dematium f.sp. epilobii conidia were suspended in a 25% v/v canola oil/water emulsion. Using this formulation, control of 4-wk-old seedlings was obtained with a 10-fold reduction in inoculum concentration (1 × 108 conidia/m2), the required dew period was reduced to 12 h, and the effect of the temperature during the dew period was minimized. In the field, C. dematium f.sp. epilobii alone or when amended with an oil emulsion failed to control fireweed growth. When the oil formulation of C. dematium f.sp. epilobii was tank mixed with a low rate of glyphosate, high levels of control were consistently achieved. Growth reduction achieved with this formulation was more than additive, suggesting a synergistic interaction. The effectiveness of the formulated conidial suspension of C. dematium f.sp. epilobii decreased with plant maturity, and 15-wk-old plants were not controlled. C. dematium f.sp. epilobii alone has limited potential as a candidate bioherbicide, but when formulated in an oil/water emulsion and combined with low rates of glyphosate, suppression of fireweed can be attained in the field.
Soil Microbial Root Colonization of Glyphosate-Treated Giant Ragweed (Ambrosia trifida), Horseweed (Conyza canadensis), and Common Lambsquarters (Chenopodium album) Biotypes
- Jessica R. Schafer, Steven G. Hallett, William G. Johnson
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- Journal:
- Weed Science / Volume 61 / Issue 2 / June 2013
- Published online by Cambridge University Press:
- 20 January 2017, pp. 289-295
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Root colonization by soil microorganisms has been shown to increase the activity of glyphosate in resistant and susceptible biotypes of giant ragweed and a susceptible common lambsquarters biotype, but not in horseweed biotypes. The objective of this study was to investigate the colonization of roots in glyphosate-resistant and -susceptible giant ragweed and horseweed biotypes, and glyphosate-tolerant and -susceptible biotypes of common lambsquarters after a sublethal glyphosate application. The three weed species were grown separately in sterile and unsterile field soil and treated with glyphosate at two sublethal rates. Soil microbes were isolated from the roots onto sterile media 3 d after the glyphosate treatment. The susceptible biotypes of giant ragweed and horseweed grown in unsterile soil were colonized by more soil microbes at the higher rate of glyphosate, compared to the resistant biotype grown in unsterile soil. Oomycetes were isolated separately on a selective media and they were also more prevalent in the roots of the susceptible biotypes of each weed species grown in the unsterile soil when glyphosate was applied at the highest rate. Therefore, the ability of these three weed species to tolerate a glyphosate application may involve differences in the susceptibility to soil microbial colonization, especially oomycetes.
Rhizosphere Microbial Community Dynamics in Glyphosate-Treated Susceptible and Resistant Biotypes of Giant Ragweed (Ambrosia trifida)
- Jessica R. Schafer, Steven G. Hallett, William G. Johnson
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- Journal:
- Weed Science / Volume 62 / Issue 2 / June 2014
- Published online by Cambridge University Press:
- 20 January 2017, pp. 370-381
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In a previous study, glyphosate-susceptible and -resistant giant ragweed biotypes grown in sterile field soil survived a higher rate of glyphosate than those grown in unsterile field soil, and the roots of the susceptible biotype were colonized by a larger number of soil microorganisms than those of the resistant biotype when treated with 1.6 kg ae ha−1 glyphosate. Thus, we concluded that soil-borne microbes play a role in glyphosate activity and now hypothesize that the ability of the resistant biotype to tolerate glyphosate may involve microbial interactions in the rhizosphere. The objective of this study was to evaluate differences in the rhizosphere microbial communities of glyphosate-susceptible and -resistant giant ragweed biotypes 3 d after a glyphosate treatment. Giant ragweed biotypes were grown in the greenhouse in unsterile field soil and glyphosate was applied at either 0 or 1.6 kg ha−1. Rhizosphere soil was sampled 3 d after the glyphosate treatment, and DNA was extracted, purified, and sequenced with the use of Illumina Genome Analyzer next-generation sequencing. The taxonomic distribution of the microbial community, diversity, genera abundance, and community structure within the rhizosphere of the two giant ragweed biotypes in response to a glyphosate application was evaluated by metagenomics analysis. Bacteria comprised approximately 96% of the total microbial community in both biotypes, and differences in the distribution of some microbes at the phyla level were observed. Select soil-borne plant pathogens (Verticillium and Xanthomonas) and plant-growth–promoting rhizobacteria (Burkholderia) present in the rhizosphere were influenced by either biotype or glyphosate application. We did not, however, observe large differences in the diversity or structure of soil microbial communities among our treatments. The results of this study indicate that challenging giant ragweed biotypes with glyphosate causes perturbations in rhizosphere microbial communities and that the perturbations differ between the susceptible and resistant biotypes. However, biological relevance of the rhizosphere microbial community data that we obtained by next-generation sequencing remains unclear.
Herbicidal spectrum and activity of Myrothecium verrucaria
- Kathleen I. Anderson, Steven G. Hallett
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- Journal:
- Weed Science / Volume 52 / Issue 4 / August 2004
- Published online by Cambridge University Press:
- 20 January 2017, pp. 623-627
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Myrothecium verrucaria, isolated from sicklepod, was investigated for bioherbicide potential against a wide range of economically important weed species from agronomic, pasture, and horticultural systems. A number of different weed species from a range of plant families were highly susceptible to sprays of crude preparations of the fungus. A small number of species, primarily monocots, were tolerant, showing no damage symptoms or insignificant effects on biomass. Symptoms developed very rapidly in susceptible hosts, suggesting the activity of toxins, several of which are known to be produced by Myrothecium spp. The activity of crude harvests of M. verrucaria was not diminished when they were filtered to remove fungal mycelium and spores. In contrast, washed conidia had relatively little impact on weed species. We conclude that the activity of M. verrucaria is primarily caused by the activity of metabolites produced by the fungus in culture and not due to infection by the fungus per se. Myrothecium verrucaria cultural preparations have extremely potent herbicidal properties, but given its ability to produce mammalian toxins, we caution against its use.
Effect of Nozzle Type and Pressure on the Efficacy of Spray Applications of the Bioherbicidal Fungus Microsphaeropsis amaranthi
- David A. Doll, Paul E. Sojka, Steven G. Hallett
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- Journal:
- Weed Technology / Volume 19 / Issue 4 / December 2005
- Published online by Cambridge University Press:
- 20 January 2017, pp. 918-923
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The effect of application technology on efficacy has been thoroughly investigated for sprays of chemical pesticide but not biological pesticides. This study investigates the effect of applying conidia of Microsphaeropsis amaranthi, a candidate bioherbicide for Amaranthus spp., with a range of different hydraulic nozzle tips. The nozzle tips were selected to deliver sprays with different spectra of droplet sizes deployed at different angles. We found that sprays of large droplets gave poor coverage of the target and resulted in low levels of disease severity on common waterhemp. The most effective nozzle tip tested was a hollow cone nozzle tip, such as is commonly used for the application of fungicides. This nozzle tip deployed large numbers of fine droplets that swirled within the plant canopy, provided good coverage of all plant parts, and resulted in the highest levels of disease severity, particularly on stems.
Where are the bioherbicides?
- Steven G. Hallett
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- Journal:
- Weed Science / Volume 53 / Issue 3 / June 2005
- Published online by Cambridge University Press:
- 20 January 2017, pp. 404-415
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Since commercialization of Collego™ and Devine™ in the early 1980s, there has been a small but consistent research effort in the area of bioherbicides. The bioherbicide approach has promised effective weed management in cropping systems where the classical approach (using exotic natural enemies) is largely unsuitable. The overriding principle of the bioherbicide approach has been that a host-specific, coevolved natural enemy can be used as a bioherbicide when applied in simple formulations at inundative levels; however, two decades of research has effectively disproven this principle. Although research has revealed weaknesses in the bioherbicide approach, it has also revealed potential in a number of areas. A number of niche situations will remain in which host-specific plant pathogens can be developed as bioherbicides, such as for parasitic weeds and narcotic plants, but more research should be conducted with virulent, broad host range organisms, and more effort should be devoted to developing techniques for the cultural and genetic enhancement of bioherbicidal organisms.
Variable Response of Common Waterhemp (Amaranthus rudis) Populations and Individuals to Glyphosate
- David A. Smith, Steven G. Hallett
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- Journal:
- Weed Technology / Volume 20 / Issue 2 / June 2006
- Published online by Cambridge University Press:
- 20 January 2017, pp. 466-471
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Putatively resistant (PR) and putatively susceptible (PS) common waterhemp populations were grown in the greenhouse and sprayed at the three- to four-leaf stage with glyphosate (0.63 kg ae/ha). Surviving plants from PR populations and randomly selected plants from PS populations were clonally propagated and the clones were sprayed with 0.1 to 10.0 kg/ha glyphosate. The glyphosate rates required to reduce growth by 50% (GR50) among the clones were relatively similar, but the concentration required to reduce growth by 90% (GR90) ranged from 1.5 to 16.3 kg/ha. The concentration of glyphosate required to kill 90% of plants (LD90) ranged from 2.3 kg/ha to over 10.0 kg/ ha. This range of responses to glyphosate in common waterhemp clones from different parts of the Midwestern United States indicates a risk of evolution of resistance in common waterhemp populations that are repeatedly selected by applications of glyphosate in the field.
Dislocation from coevolved relationships: a unifying theory for plant invasion and naturalization?
- Steven G. Hallett
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- Journal:
- Weed Science / Volume 54 / Issue 2 / April 2006
- Published online by Cambridge University Press:
- 20 January 2017, pp. 282-290
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Invasions of many different plants have occurred in ecosystems around the world and theories of the mechanisms of these invasions abound. All the proposed theories have value, and many of the proposed mechanisms may at least serve as facilitating factors, but no overarching conceptual framework for the mechanisms of plant invasion has emerged. One common theme in all invasions is that the invading plant, in the process of geographic displacement, has been dislocated from its coevolved biota and relocated with a less-familiar biota. The impacts of dislocation from coevolved mutualists, parasites, and competitors are different but follow general principles. The impacts of relocation with new mutualists, parasites, and competitors are also variable and will change as the introduced plant coevolves with its new biotic environment. I propose some hypotheses to guide predictions of the outcomes of the dislocation of plants from coevolved relationships and, hence, the outcomes of plant geographic displacement. Invasiveness in plants is not determined by their life history traits or the nature of the ecosystem they are invading. Invasiveness is primarily a result of the process of invasion itself. When plants are dislocated from coevolved relationships and confronted with new relationships, they can become ecologically transformed. This transformation can affect the ability of a plant population to become established, invasive, and naturalized in a new environment.
Weed seed mortality in soils with contrasting agricultural management histories
- Adam S. Davis, Kathleen I. Anderson, Steven G. Hallett, Karen A. Renner
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- Journal:
- Weed Science / Volume 54 / Issue 2 / April 2006
- Published online by Cambridge University Press:
- 20 January 2017, pp. 291-297
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It has been proposed that cropping systems can be managed to promote the development of soil microbial communities that accelerate weed seed mortality. We examined soil fungal and bacterial communities, soil C:N ratio, soil particle size fractions, and weed seed mortality in soil from fields with over 10 yr of five contrasting management histories with the objective of determining if seed mortality could be explained by differences in soil properties. Seed mortality of giant foxtail and velvetleaf were greatest in soil from the conventionally managed systems and lowest in soil from a reduced input system. Principal-components analysis of soil microbial communities, as determined through denaturing gradient gel electrophoresis of polymerase chain reaction–amplified ribosomal RNA genes (PCR-DGGE), showed distinct differences in the composition of fungal and bacterial communities among the study soils. The first principal component of the 18S rDNA PCR-DGGE analysis of fungal community composition showed a strong negative correlation with both giant foxtail (− 0.52, P < 0.05) and velvetleaf (− 0.57, P < 0.01) seed mortality, as did ordination with nonmetric multidimensional scaling (NMS) [giant foxtail (− 0.54, P < 0.01) and velvetleaf (− 0.60, P < 0.01)], suggesting that seeds of the two species were affected similarly by changes in the soil fungal community. For giant foxtail, weed seed mortality was also positively correlated (r = 0.48, P < 0.05) with the first NMS axis of the bacterial 16S rDNA analysis. None of the other measured soil properties were significantly correlated with weed seed mortality. Thus, for the soils tested here, management history, microbial community composition, and weed seed mortality were linked. To extend these results to the field, more work is needed to identify components of the fungal and bacterial communities that are active in seed degradation, and to develop conservation biocontrol recommendations for these species.
Response of Giant Ragweed (Ambrosia trifida), Horseweed (Conyza canadensis), and Common Lambsquarters (Chenopodium album) Biotypes to Glyphosate in the Presence and Absence of Soil Microorganisms
- Jessica R. Schafer, Steven G. Hallett, William G. Johnson
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- Journal:
- Weed Science / Volume 60 / Issue 4 / December 2012
- Published online by Cambridge University Press:
- 20 January 2017, pp. 641-649
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In previous research conducted on nonweed species, the efficacy of glyphosate was shown to be greater in unsterile soils compared to sterile soils and soil microorganisms were found to play an important role in glyphosate efficacy. Conducting greenhouse studies in microbe-free soil may therefore produce unreliable data, leading to erroneous conclusions. The objective of this study was to determine the effect of soil microorganisms on the response of glyphosate-resistant and -susceptible biotypes of three problematic weeds of the midwestern United States: giant ragweed, horseweed, and common lambsquarters. A greenhouse dose–response study was conducted on each of the three weed species grown in sterile and unsterile field soil, and the dry weight response of roots and shoots was measured. The three weed species responded differently to glyphosate when grown in the sterile and unsterile soil; that is, in the presence and absence of soil microbes. Soil microbes influenced the response of the susceptible and resistant giant ragweed biotypes and the susceptible common lambsquarters, but not the tolerant common lambsquarters or either horseweed biotype. The different responses of the three species to glyphosate in the presence and absence of soil microbes demonstrates that rhizosphere interactions are fundamental to the mode of action of glyphosate. These findings suggest that the range of tolerance to glyphosate observed in weeds and the evolution of resistance in weed biotypes may also be influenced by rhizosphere interactions. The soil media used in dose–response screenings to identify susceptible and resistant weed biotypes is very important. Unsterile field soil should be incorporated into growth media when conducting dose–response screenings to avoid false-positive results. In addition, researchers performing glyphosate dose–response assays should be aware of these findings.
Heritability of Glyphosate Resistance in Indiana Horseweed (Conyza canadensis) Populations
- Vince M. Davis, Greg R. Kruger, Steven G. Hallett, Patrick J. Tranel, William G. Johnson
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- Journal:
- Weed Science / Volume 58 / Issue 1 / March 2010
- Published online by Cambridge University Press:
- 20 January 2017, pp. 30-38
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Horseweed has rapidly become a major weed in soybean and cotton production fields of the United States, and Indiana farmers ranked horseweed as one of the five worst weeds in their fields during a mail survey in 2003. Glyphosate resistance in horseweed is conferred by a single, incompletely dominant gene. Horseweed populations possess a high level of variability in their response to glyphosate. Horseweed has also evolved resistance to acetolactate synthase (ALS) inhibitors, and biotypes resistant to ALS-inhibiting herbicides and glyphosate are in many of the same areas. An experiment was designed to determine whether glyphosate resistance can be transferred by pollen. We found glyphosate-resistant plants in 1.1 to 3.8% of the progeny. Segregation ratios fit the expected 3 : 1 resistant : sensitive ratios confirming that glyphosate resistance in horseweed can transfer to closely located glyphosate-susceptible biotypes under open-pollinated conditions at low frequencies. The hypothesis of a follow-up experiment was that first-generation progeny of parent plants, selected on a continuum of low to high phenotypic response to glyphosate, will inherit respective low to high phenotypic responses to glyphosate. The variability in field-collected populations (low-level to high-level glyphosate resistance) ranged from 2 to 14 times the commonly recommended field use rate of glyphosate. However, low- and high-levels of glyphosate resistance were not observed in first-generation progeny. We conclude that differential glyphosate responses observed among parental populations was due to different frequencies of the resistance allele within the populations, rather than the presence of different resistance alleles.
Influence of Winter Annual Weed Removal Timings on Soybean Cyst Nematode Population Density and Plant Biomass
- Valerie A. Mock, J. Earl Creech, Virginia R. Ferris, Steven G. Hallett, William G. Johnson
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- Journal:
- Weed Science / Volume 58 / Issue 4 / December 2010
- Published online by Cambridge University Press:
- 20 January 2017, pp. 381-386
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Soybean cyst nematode (SCN) is one of the most yield limiting pathogens in U.S. soybean production. Henbit and purple deadnettle are winter annual weeds shown to facilitate SCN reproduction after crop harvest in the eastern Corn Belt. These weeds, along with volunteer soybean that germinates in autumn after harvest, are common to postharvest soybean production fields and provide an opportunity for SCN reproduction and population increase outside of the typical soybean production season. The objective of this experiment was to determine if autumn removal of these weeds and volunteer soybean can influence the winter weed seedbank, plant biomass, and SCN population densities. Microplots were established with or without Lamium spp. and volunteer soybean, and four winter weed removal timings (none, October, December, and May). Dry weights of autumn Lamium spp. were reduced 50% in October when grown in competition with volunteer soybean. SCN juveniles were found in henbit roots at higher densities in October (42 per gram of root) than December (5 per gram of root) and were also found in the roots of volunteer soybean (14 per gram of root) in October. SCN egg population densities were 50% lower in August after the summer fallow period. The results of this experiment suggest that autumn removal of winter annual weeds and volunteer soybean did not reduce SCN populations.
Interactions between chemical herbicides and the candidate bioherbicide Microsphaeropsis amaranthi
- David A. Smith, Steven G. Hallett
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- Journal:
- Weed Science / Volume 54 / Issue 3 / June 2006
- Published online by Cambridge University Press:
- 20 January 2017, pp. 532-537
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The fungal plant pathogen Microsphaeropsis amaranthi is virulent against a number of key weeds in the Amaranthaceae, including common waterhemp, and is under investigation as a bioherbicide. Common waterhemp has become a key weed in midwestern crop production systems and is a good target for a bioherbicide that could be integrated into weed management systems. We investigated the direct effects of a range of chemical herbicides and adjuvants upon conidia of M. amaranthi and found that many herbicides and most adjuvants were strongly inhibitory to germination. On the other hand, M. amaranthi was compatible with a selection of postemergence herbicides commonly used in midwestern weed management systems, including carfentrazone, chloransulam, and imazethapyr. Most glyphosate products suppressed or abolished germination of M. amaranthi conidia, but by testing adjuvants commonly used in glyphosate products and technical-grade glyphosate salts, it was revealed that this inhibition was due to formulation additives and not the active ingredient. When glyphosate and conidia of M. amaranthi were sprayed onto common waterhemp seedlings, the herbicide predisposed plants to infection by M. amaranthi. When M. amaranthi was applied 1 to 3 d after glyphosate, the glyphosate rate required to control common waterhemp was reduced by half. Similar results were observed on clones propagated from a common waterhemp plant resistant to glyphosate. When M. amaranthi was applied to seedlings 2 d before glyphosate, the efficacy of the herbicide was reduced. These findings demonstrate that positive interactions between herbicides and M. amaranthi exist but reveal practical difficulties that may limit the integration of the strategy in the field.
Hydroponic production of vegetable Amaranth (Amaranthus cruentus) for improving nutritional security and economic viability in Kenya
- Marcia M. Croft, Steven G. Hallett, Maria I. Marshall
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- Journal:
- Renewable Agriculture and Food Systems / Volume 32 / Issue 6 / December 2017
- Published online by Cambridge University Press:
- 09 January 2017, pp. 552-561
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This study used a multidisciplinary approach to evaluate the potential for hydroponic production of vegetable amaranth (Amaranthus cruentus) in Kenya. Hydroponic systems have potential for increased efficiency in water and land use, but their potential has not been critically evaluated in many developing countries. To address this gap in knowledge, this study assessed the nutritional density and economic viability of hydroponic systems built from local materials. Specifically, vegetable amaranth was grown hydroponically and evaluated for increased nutritional density of key micronutrients. Manipulation of the nutrient solution used in hydroponic systems changed the bioaccumulation of zinc, iron and carotenoids, which are three of the most common micronutrients lacking in Kenyan diets. Economic viability was assessed with a benefit-cost analysis that compared three different hydroponic systems to soil-based production and purchasing vegetables from local markets. This analysis showed that none of the hydroponic systems were profitable under current conditions, but sensitivity analyses revealed certain scenarios where they could become so. Overall, hydroponic production has the potential to create nutrient-dense crops with high levels of zinc, iron, or carotenoids. However, hydroponic systems may be better suited to crops of higher value than amaranth, areas where soil-based production is not an option, or regions where vegetable markets are not available.
Contributors
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- By Mitchell Aboulafia, Frederick Adams, Marilyn McCord Adams, Robert M. Adams, Laird Addis, James W. Allard, David Allison, William P. Alston, Karl Ameriks, C. Anthony Anderson, David Leech Anderson, Lanier Anderson, Roger Ariew, David Armstrong, Denis G. Arnold, E. J. Ashworth, Margaret Atherton, Robin Attfield, Bruce Aune, Edward Wilson Averill, Jody Azzouni, Kent Bach, Andrew Bailey, Lynne Rudder Baker, Thomas R. Baldwin, Jon Barwise, George Bealer, William Bechtel, Lawrence C. Becker, Mark A. Bedau, Ernst Behler, José A. Benardete, Ermanno Bencivenga, Jan Berg, Michael Bergmann, Robert L. Bernasconi, Sven Bernecker, Bernard Berofsky, Rod Bertolet, Charles J. Beyer, Christian Beyer, Joseph Bien, Joseph Bien, Peg Birmingham, Ivan Boh, James Bohman, Daniel Bonevac, Laurence BonJour, William J. Bouwsma, Raymond D. Bradley, Myles Brand, Richard B. Brandt, Michael E. Bratman, Stephen E. Braude, Daniel Breazeale, Angela Breitenbach, Jason Bridges, David O. Brink, Gordon G. Brittan, Justin Broackes, Dan W. Brock, Aaron Bronfman, Jeffrey E. Brower, Bartosz Brozek, Anthony Brueckner, Jeffrey Bub, Lara Buchak, Otavio Bueno, Ann E. Bumpus, Robert W. Burch, John Burgess, Arthur W. Burks, Panayot Butchvarov, Robert E. Butts, Marina Bykova, Patrick Byrne, David Carr, Noël Carroll, Edward S. Casey, Victor Caston, Victor Caston, Albert Casullo, Robert L. Causey, Alan K. L. Chan, Ruth Chang, Deen K. Chatterjee, Andrew Chignell, Roderick M. Chisholm, Kelly J. Clark, E. J. Coffman, Robin Collins, Brian P. Copenhaver, John Corcoran, John Cottingham, Roger Crisp, Frederick J. Crosson, Antonio S. Cua, Phillip D. Cummins, Martin Curd, Adam Cureton, Andrew Cutrofello, Stephen Darwall, Paul Sheldon Davies, Wayne A. Davis, Timothy Joseph Day, Claudio de Almeida, Mario De Caro, Mario De Caro, John Deigh, C. F. Delaney, Daniel C. Dennett, Michael R. DePaul, Michael Detlefsen, Daniel Trent Devereux, Philip E. Devine, John M. Dillon, Martin C. Dillon, Robert DiSalle, Mary Domski, Alan Donagan, Paul Draper, Fred Dretske, Mircea Dumitru, Wilhelm Dupré, Gerald Dworkin, John Earman, Ellery Eells, Catherine Z. Elgin, Berent Enç, Ronald P. Endicott, Edward Erwin, John Etchemendy, C. Stephen Evans, Susan L. Feagin, Solomon Feferman, Richard Feldman, Arthur Fine, Maurice A. Finocchiaro, William FitzPatrick, Richard E. Flathman, Gvozden Flego, Richard Foley, Graeme Forbes, Rainer Forst, Malcolm R. Forster, Daniel Fouke, Patrick Francken, Samuel Freeman, Elizabeth Fricker, Miranda Fricker, Michael Friedman, Michael Fuerstein, Richard A. Fumerton, Alan Gabbey, Pieranna Garavaso, Daniel Garber, Jorge L. A. Garcia, Robert K. Garcia, Don Garrett, Philip Gasper, Gerald Gaus, Berys Gaut, Bernard Gert, Roger F. Gibson, Cody Gilmore, Carl Ginet, Alan H. Goldman, Alvin I. Goldman, Alfonso Gömez-Lobo, Lenn E. Goodman, Robert M. Gordon, Stefan Gosepath, Jorge J. E. Gracia, Daniel W. Graham, George A. Graham, Peter J. Graham, Richard E. Grandy, I. Grattan-Guinness, John Greco, Philip T. Grier, Nicholas Griffin, Nicholas Griffin, David A. Griffiths, Paul J. Griffiths, Stephen R. Grimm, Charles L. Griswold, Charles B. Guignon, Pete A. Y. Gunter, Dimitri Gutas, Gary Gutting, Paul Guyer, Kwame Gyekye, Oscar A. Haac, Raul Hakli, Raul Hakli, Michael Hallett, Edward C. Halper, Jean Hampton, R. James Hankinson, K. R. Hanley, Russell Hardin, Robert M. Harnish, William Harper, David Harrah, Kevin Hart, Ali Hasan, William Hasker, John Haugeland, Roger Hausheer, William Heald, Peter Heath, Richard Heck, John F. Heil, Vincent F. Hendricks, Stephen Hetherington, Francis Heylighen, Kathleen Marie Higgins, Risto Hilpinen, Harold T. Hodes, Joshua Hoffman, Alan Holland, Robert L. Holmes, Richard Holton, Brad W. Hooker, Terence E. Horgan, Tamara Horowitz, Paul Horwich, Vittorio Hösle, Paul Hoβfeld, Daniel Howard-Snyder, Frances Howard-Snyder, Anne Hudson, Deal W. Hudson, Carl A. Huffman, David L. Hull, Patricia Huntington, Thomas Hurka, Paul Hurley, Rosalind Hursthouse, Guillermo Hurtado, Ronald E. Hustwit, Sarah Hutton, Jonathan Jenkins Ichikawa, Harry A. Ide, David Ingram, Philip J. Ivanhoe, Alfred L. Ivry, Frank Jackson, Dale Jacquette, Joseph Jedwab, Richard Jeffrey, David Alan Johnson, Edward Johnson, Mark D. Jordan, Richard Joyce, Hwa Yol Jung, Robert Hillary Kane, Tomis Kapitan, Jacquelyn Ann K. Kegley, James A. Keller, Ralph Kennedy, Sergei Khoruzhii, Jaegwon Kim, Yersu Kim, Nathan L. King, Patricia Kitcher, Peter D. Klein, E. D. Klemke, Virginia Klenk, George L. Kline, Christian Klotz, Simo Knuuttila, Joseph J. Kockelmans, Konstantin Kolenda, Sebastian Tomasz Kołodziejczyk, Isaac Kramnick, Richard Kraut, Fred Kroon, Manfred Kuehn, Steven T. Kuhn, Henry E. Kyburg, John Lachs, Jennifer Lackey, Stephen E. Lahey, Andrea Lavazza, Thomas H. Leahey, Joo Heung Lee, Keith Lehrer, Dorothy Leland, Noah M. Lemos, Ernest LePore, Sarah-Jane Leslie, Isaac Levi, Andrew Levine, Alan E. Lewis, Daniel E. Little, Shu-hsien Liu, Shu-hsien Liu, Alan K. L. Chan, Brian Loar, Lawrence B. Lombard, John Longeway, Dominic McIver Lopes, Michael J. Loux, E. J. Lowe, Steven Luper, Eugene C. Luschei, William G. Lycan, David Lyons, David Macarthur, Danielle Macbeth, Scott MacDonald, Jacob L. Mackey, Louis H. Mackey, Penelope Mackie, Edward H. Madden, Penelope Maddy, G. B. Madison, Bernd Magnus, Pekka Mäkelä, Rudolf A. Makkreel, David Manley, William E. Mann (W.E.M.), Vladimir Marchenkov, Peter Markie, Jean-Pierre Marquis, Ausonio Marras, Mike W. Martin, A. P. Martinich, William L. McBride, David McCabe, Storrs McCall, Hugh J. McCann, Robert N. McCauley, John J. McDermott, Sarah McGrath, Ralph McInerny, Daniel J. McKaughan, Thomas McKay, Michael McKinsey, Brian P. McLaughlin, Ernan McMullin, Anthonie Meijers, Jack W. Meiland, William Jason Melanson, Alfred R. Mele, Joseph R. Mendola, Christopher Menzel, Michael J. Meyer, Christian B. Miller, David W. Miller, Peter Millican, Robert N. Minor, Phillip Mitsis, James A. Montmarquet, Michael S. Moore, Tim Moore, Benjamin Morison, Donald R. Morrison, Stephen J. Morse, Paul K. Moser, Alexander P. D. Mourelatos, Ian Mueller, James Bernard Murphy, Mark C. Murphy, Steven Nadler, Jan Narveson, Alan Nelson, Jerome Neu, Samuel Newlands, Kai Nielsen, Ilkka Niiniluoto, Carlos G. Noreña, Calvin G. Normore, David Fate Norton, Nikolaj Nottelmann, Donald Nute, David S. Oderberg, Steve Odin, Michael O’Rourke, Willard G. Oxtoby, Heinz Paetzold, George S. Pappas, Anthony J. Parel, Lydia Patton, R. P. Peerenboom, Francis Jeffry Pelletier, Adriaan T. Peperzak, Derk Pereboom, Jaroslav Peregrin, Glen Pettigrove, Philip Pettit, Edmund L. Pincoffs, Andrew Pinsent, Robert B. Pippin, Alvin Plantinga, Louis P. Pojman, Richard H. Popkin, John F. Post, Carl J. Posy, William J. Prior, Richard Purtill, Michael Quante, Philip L. Quinn, Philip L. Quinn, Elizabeth S. Radcliffe, Diana Raffman, Gerard Raulet, Stephen L. Read, Andrews Reath, Andrew Reisner, Nicholas Rescher, Henry S. Richardson, Robert C. Richardson, Thomas Ricketts, Wayne D. Riggs, Mark Roberts, Robert C. Roberts, Luke Robinson, Alexander Rosenberg, Gary Rosenkranz, Bernice Glatzer Rosenthal, Adina L. Roskies, William L. Rowe, T. M. Rudavsky, Michael Ruse, Bruce Russell, Lilly-Marlene Russow, Dan Ryder, R. M. Sainsbury, Joseph Salerno, Nathan Salmon, Wesley C. Salmon, Constantine Sandis, David H. Sanford, Marco Santambrogio, David Sapire, Ruth A. Saunders, Geoffrey Sayre-McCord, Charles Sayward, James P. Scanlan, Richard Schacht, Tamar Schapiro, Frederick F. Schmitt, Jerome B. Schneewind, Calvin O. Schrag, Alan D. Schrift, George F. Schumm, Jean-Loup Seban, David N. Sedley, Kenneth Seeskin, Krister Segerberg, Charlene Haddock Seigfried, Dennis M. Senchuk, James F. Sennett, William Lad Sessions, Stewart Shapiro, Tommie Shelby, Donald W. Sherburne, Christopher Shields, Roger A. Shiner, Sydney Shoemaker, Robert K. Shope, Kwong-loi Shun, Wilfried Sieg, A. John Simmons, Robert L. Simon, Marcus G. Singer, Georgette Sinkler, Walter Sinnott-Armstrong, Matti T. Sintonen, Lawrence Sklar, Brian Skyrms, Robert C. Sleigh, Michael Anthony Slote, Hans Sluga, Barry Smith, Michael Smith, Robin Smith, Robert Sokolowski, Robert C. Solomon, Marta Soniewicka, Philip Soper, Ernest Sosa, Nicholas Southwood, Paul Vincent Spade, T. L. S. Sprigge, Eric O. Springsted, George J. Stack, Rebecca Stangl, Jason Stanley, Florian Steinberger, Sören Stenlund, Christopher Stephens, James P. Sterba, Josef Stern, Matthias Steup, M. A. Stewart, Leopold Stubenberg, Edith Dudley Sulla, Frederick Suppe, Jere Paul Surber, David George Sussman, Sigrún Svavarsdóttir, Zeno G. Swijtink, Richard Swinburne, Charles C. Taliaferro, Robert B. Talisse, John Tasioulas, Paul Teller, Larry S. Temkin, Mark Textor, H. S. Thayer, Peter Thielke, Alan Thomas, Amie L. Thomasson, Katherine Thomson-Jones, Joshua C. Thurow, Vzalerie Tiberius, Terrence N. Tice, Paul Tidman, Mark C. Timmons, William Tolhurst, James E. Tomberlin, Rosemarie Tong, Lawrence Torcello, Kelly Trogdon, J. D. Trout, Robert E. Tully, Raimo Tuomela, John Turri, Martin M. Tweedale, Thomas Uebel, Jennifer Uleman, James Van Cleve, Harry van der Linden, Peter van Inwagen, Bryan W. Van Norden, René van Woudenberg, Donald Phillip Verene, Samantha Vice, Thomas Vinci, Donald Wayne Viney, Barbara Von Eckardt, Peter B. M. Vranas, Steven J. Wagner, William J. Wainwright, Paul E. Walker, Robert E. Wall, Craig Walton, Douglas Walton, Eric Watkins, Richard A. Watson, Michael V. Wedin, Rudolph H. Weingartner, Paul Weirich, Paul J. Weithman, Carl Wellman, Howard Wettstein, Samuel C. Wheeler, Stephen A. White, Jennifer Whiting, Edward R. Wierenga, Michael Williams, Fred Wilson, W. Kent Wilson, Kenneth P. Winkler, John F. Wippel, Jan Woleński, Allan B. Wolter, Nicholas P. Wolterstorff, Rega Wood, W. Jay Wood, Paul Woodruff, Alison Wylie, Gideon Yaffe, Takashi Yagisawa, Yutaka Yamamoto, Keith E. Yandell, Xiaomei Yang, Dean Zimmerman, Günter Zoller, Catherine Zuckert, Michael Zuckert, Jack A. Zupko (J.A.Z.)
- Edited by Robert Audi, University of Notre Dame, Indiana
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- Book:
- The Cambridge Dictionary of Philosophy
- Published online:
- 05 August 2015
- Print publication:
- 27 April 2015, pp ix-xxx
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