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| Web URL(s): | http://www.newss.org/proceedings/proceedings_2005.pdf#page=43
Last checked: 07/22/2013
Requires: PDF Reader
Notes: Item is within a single large file |
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| Publication Type:
| Report |
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| Content Type: | Abstract or Summary only |
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| Author(s): | Maxwell, B. D. |
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| Author Affiliation: | Montana State University, Bozeman |
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| Title: | Herbicide resistance management: What have we learned? |
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| Section: | General symposium
Other records with the "General symposium" Section
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| Meeting Info.: | Capital Hilton, Washington, D.C.: January 3-6, 2005 |
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| Source: | Proceedings: NortheasternWeed Science Society. Vol. 59, 2005, p. 29. |
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| Publishing Information: | Ithaca, NY: Northeastern Weed Science Society |
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| # of Pages: | 1 |
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| Keywords: | TIC Keywords: Models; Herbicide resistance; Anilazine; Weed resistance to herbicides; Dominant genes; Genetic drift; Preventive control
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| Abstract/Contents: | "Herbicide resistance was initially regarded as a weed biology phenomenon of purely academic interest. Cases of weed resistance to the triazine herbicides became common, but were not regarded as a major management problem because there were alternative herbicides and the reduced fitness of the resistant phenotype prevented populations from expanding when triazine herbicides were not used. By the 1980s, cases of resistance to a wide array of herbicide modes-of-action raised the concern for managing the phenomenon. The severity of the issue was compounded because the resistance was primarily due to single allele dominant trait with little fitness penalty. Development of management strategies was, and continues to be, hindered by two major problems. First, it is very difficult to experimentally select for resistance and follow its evolution, frequency and spread in populations under a range of management practices. Seeds from resistant weeds have been collected, screened for resistance and their progeny or pure-bred progeny lines created for experimentation. This empirical approach to understanding the basic physiology of resistance has been fruitful, but it provides little ecological context and has not been effective for understanding the population or community biology that is relevant for development of management strategies. Second, there is reluctance by the herbicide industry to admit that resistance to their products exists until it is well characterized and documented, and once resistance is established, management practices that include products from other companies or non-chemical practices have not been encouraged. Given these constraints to developing resistance management strategies, the discipline has largely turned to models to predict resistance evolution and spread and subsequent management strategies. Models have been used to examine preventative and reactive resistance management approaches. Results from simulation experiments generally suggest that prevention may best be accomplished by a reduction in selection intensity by reducing the efficacy on susceptible phenotype reproduction. Models used to investigate preventative stratefies have showed that reduced herbicide efficacy and subsequent selection for resistance can be accomplished by reducing rates to non-lethal doses, not applying to the entire population (leaving susceptible refugia), and reducing the frequency of use over time through crop rotations where different modes-of-action herbicides can be rotated or non-chemical means can be used. Modeling of reactive management approaches (i.e. once resistance is at a high frequency in a weed population) has been limited to causing a weed species shift away from the resistant species by changing crops or production system (e.g. crops to grazing), or relying on differential fitness to select against the resistant phenotype when the selective agent (herbicide) is removed from the system. The models have demonstrated the benefit of some strategies over others and have been variously promoted in industry and extension literature." |
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| Language: | English |
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| References: | 0 |
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| Note: | This item is an abstract only! |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Maxwell, B. D. 2005. Herbicide resistance management: What have we learned?. Proc. Annu. Meet. Northeast. Weed Sci. Soc. 59:p. 29. |
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| Web URL(s):
http://www.newss.org/proceedings/proceedings_2005.pdf#page=43
Last checked: 07/22/2013
Requires: PDF Reader
Notes: Item is within a single large file |
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MSU catalog number: SB 610 .N62 v. 57 |
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