scholarly journals The Impact of Herbicide-Resistant Rice Technology on Phenotypic Diversity and Population Structure of United States Weedy Rice

2014 ◽  
Vol 166 (3) ◽  
pp. 1208-1220 ◽  
Author(s):  
N. R. Burgos ◽  
V. Singh ◽  
T. M. Tseng ◽  
H. Black ◽  
N. D. Young ◽  
...  
Keyword(s):  
United States ◽  
Population Structure ◽  
Phenotypic Diversity ◽  
Weedy Rice ◽  
Herbicide Resistant ◽  
The Impact

Herbicide-Resistant Weeds in the United States and Their Impact on Extension

2009 ◽  
Vol 23 (4) ◽  
pp. 599-603 ◽  
Author(s):  
Barbara A. Scott ◽  
Mark J. Vangessel ◽  
Susan White-Hansen
Keyword(s):  
United States ◽  
Crop Production ◽  
The United States ◽  
Extension Education ◽  
Weed Species ◽  
Common Lambsquarters ◽  
Herbicide Resistant ◽  
Agronomic Crops ◽  
Survey Results ◽  
The Impact

Herbicide-resistant weeds have impacted crop production throughout the United States, but the effect they have on extension programming has not been evaluated. In June 2007, 38 extension weed specialists throughout the United States, responded to a survey on herbicide-resistant (HR) weeds and the impact they are having on extension education programming. Survey results revealed that HR weeds have had a significant impact on extension programming particularly for agronomic crops. In the last 10 yr, agronomic weed specialists' extension programming was almost twice as likely to be impacted by the presence of HR weeds as compared to horticultural programming. In the next 5 yr, agronomic extension programming is twice as likely to be altered. Of 37 weed species reported, seven genera or species of weeds represented 80% of the major HR biotypes reported. These include Amaranthus species, horseweed, Setaria species, common lambsquarters, kochia, giant ragweed, and Lolium species. Five weed species (common ragweed, common lambsquarters, horseweed, kochia, and three foxtail species) exhibited weed by mode of action (MOA) interactions when evaluated as major or minor problems. Herbicide resistance problem severity differed for weed species, herbicide MOA, and crops. The results of this survey of university extension personnel confirm that HR weeds have impacted extension programming and will continue to impact programming in the future.

scholarly journals Sources of Verticillium dahliae Affecting Lettuce

2012 ◽  
Vol 102 (11) ◽  
pp. 1071-1078 ◽  
Author(s):  
Zahi K. Atallah ◽  
Karunakaran Maruthachalam ◽  
Krishna V. Subbarao
Keyword(s):  
United States ◽  
Population Structure ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Crop Production ◽  
The United States ◽  
Lettuce Seed ◽  
Disease Epidemiology ◽  
Santa Clara Valley ◽  
The Impact

Since 1995, lettuce in coastal California, where more than half of the crop in North America is grown, has consistently suffered from severe outbreaks of Verticillium wilt. The disease is confined to this region, although the pathogen (Verticillium dahliae) and the host are present in other crop production regions in California. Migration of the pathogen with infested spinach seed was previously documented, but the geographic sources of the pathogen, as well as the impact of lettuce seed sparsely infested with V. dahliae produced outside coastal California on the pathogen population in coastal California remain unclear. Population analyses of V. dahliae were completed using 16 microsatellite markers on isolates from lettuce plants in coastal California, infested lettuce seed produced in the neighboring Santa Clara Valley of California, and spinach seed produced in four major spinach seed production regions: Chile, Denmark, the Netherlands, and the United States (Washington State). California produces 80% of spinach in the United States and all seed planted with the majority infested by V. dahliae comes from the above four sources. Three globally distributed genetic populations were identified, indicating sustained migration among these distinct geographic regions with multiple spinach crops produced each year and repeated every year in coastal California. The population structure of V. dahliae from coastal California lettuce plants was heavily influenced by migration from spinach seed imported from Denmark and Washington. Conversely, the sparsely infested lettuce seed had limited or no contribution to the Verticillium wilt epidemic in coastal California. The global trade in plant and seed material is likely contributing to sustained shifts in the population structure of V. dahliae, affecting the equilibrium of native populations, and likely affecting disease epidemiology.

scholarly journals Genetically Engineered Herbicide-Resistant Crops and Herbicide-Resistant Weed Evolution in the United States

Weed Science ◽  
2017 ◽  
Vol 66 (2) ◽  
pp. 260-273 ◽  
Author(s):  
Andrew R. Kniss
Keyword(s):  
United States ◽  
The United States ◽  
Genetically Engineered ◽  
Weed Species ◽  
Herbicide Resistant ◽  
Resistant Varieties ◽  
Weed Evolution ◽  
Sites Of Action ◽  
Herbicide Use ◽  
The Impact

Genetically engineered (GE) herbicide-resistant crops have been widely adopted by farmers in the United States and other countries around the world, and these crops have caused significant changes in herbicide use patterns. GE crops have been blamed for increased problems with herbicide-resistant weeds (colloquially called by the misnomer “superweeds”); however, there has been no rigorous analysis of herbicide use or herbicide-resistant weed evolution to quantify the impact of GE crops on herbicide resistance. Here, I analyze data from the International Survey of Herbicide Resistant Weeds and the USDA and demonstrate that adoption of GE corn varieties did not reduce herbicide diversity, and therefore likely did not increase selection pressure for herbicide-resistant weeds in that crop. Adoption of GE herbicide-resistant varieties substantially reduced herbicide diversity in cotton and soybean. Increased glyphosate use in cotton and soybean largely displaced herbicides that are more likely to select for herbicide-resistant weeds, which at least partially mitigated the impact of reduced herbicide diversity. The overall rate of newly confirmed herbicide-resistant weed species to all herbicide sites of action (SOAs) has slowed in the United States since 2005. Although the number of glyphosate-resistant weeds has increased since 1998, the evolution of new glyphosate-resistant weed species as a function of area sprayed has remained relatively low compared with several other commonly used herbicide SOAs.

Wrestling with 9/11: Immigrant Perceptions and Perceptions of Immigrants

2006 ◽  
Vol 3 (2) ◽  
pp. 107-124 ◽  
Author(s):  
Caroline Brettell
Keyword(s):  
United States ◽  
Immigration Policy ◽  
Asian Indians ◽  
World Trade Center ◽  
The United States ◽  
Fort Worth ◽  
Foreign Born ◽  
Immigrant Populations ◽  
Trade Center ◽  
The Impact

Soon after 9/11 a research project to study new immigration into the Dallas Fort Worth metropolitan area got under way. In the questionnaire that was administered to 600 immigrants across five different immigrant populations (Asian Indians, Vietnamese, Mexicans, Salvadorans, and Nigerians) between 2003 and 2005 we decided to include a question about the impact of 9/11 on their lives. We asked: “How has the attack on the World Trade Center on September 11, 2001 affected your position as an immigrant in the United States?” This article analyzes the responses to this question, looking at similarities and differences across different immigrant populations. It also addresses the broader issue of how 9/11 has affected both immigration policy and attitudes toward the foreign-born in the United States. 

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