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 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.

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 Recovery Plan for Monilinia polystroma Causing Asiatic Brown Rot of Stone Fruit

2018 ◽  
Vol 19 (2) ◽  
pp. 107-124 ◽  
Author(s):  
K. D. Cox ◽  
S. M. Villani ◽  
Anna Poniatowska ◽  
Guido Schnabel ◽  
Imre Holb ◽  
...  
Keyword(s):  
United States ◽  
Crop Production ◽  
Plant Disease ◽  
Brown Rot ◽  
The United States ◽  
Stone Fruit ◽  
Fruit Rot ◽  
Eastern United States ◽  
Recovery Plan ◽  
The Impact

Stone fruit are an economically important group of specialty fruit crops in the United States. Species of the fungal genus Monilinia are some of the most important pathogens of stone fruit worldwide. These pathogens cause blossom blight, shoot blight, and brown fruit rot in temperate production regions. The most common species of Monilinia pathogenic on stone fruit include Monilinia fructicola, M. laxa, M. fructigena, and M. polystroma. Presently, neither M. polystroma, the causal agent of “Asiatic brown rot”, nor M. fructigena, one of the causal agents of “European brown rot”, have been reported in North America. Interestingly, both species can also cause brown rot of apple, which is densely planted in the eastern United States. This recovery plan was produced as part of the National Plant Disease Recovery System (NPDRS), called for in Homeland Security Presidential Directive Number 9 (HSPD-9) to ensure that the tools, infrastructure, communication networks, and capacity required to mitigate the impact of high-consequence plant disease outbreaks are such that a reasonable level of crop production is maintained. It is intended to provide a brief primer on the disease, assess the status of critical recovery components, and identify disease management research, extension, and education needs.

scholarly journals Recovery Plan for Laurel Wilt of Avocado, Caused by Raffaelea lauricola

2017 ◽  
Vol 18 (2) ◽  
pp. 51-77 ◽  
Author(s):  
R. C. Ploetz ◽  
M. A. Hughes ◽  
P. E. Kendra ◽  
S. W. Fraedrich ◽  
D. Carrillo ◽  
...  
Keyword(s):  
United States ◽  
Crop Production ◽  
Plant Disease ◽  
Value Added ◽  
The United States ◽  
Persea Americana ◽  
Laurel Wilt ◽  
Recovery Plan ◽  
Raffaelea Lauricola ◽  
The Impact

Laurel wilt kills American members of the Lauraceae plant family, including avocado (Persea americana). The disease threatens commercial production in the United States and other countries, and currently impacts the avocado industry in Florida. As laurel wilt spreads, the National Germplasm Repository for avocado in Miami (USDA-ARS) and commercial and residential production in other states (e.g., California and Hawaii), U.S. protectorates (Puerto Rico), and other countries are at risk. In the United States, value-added production of avocado of more than $1.3 billion/year is threatened. This recovery plan was produced as part of the National Plant Disease Recovery System (NPDRS), called for in Homeland Security Presidential Directive Number 9 (HSPD-9) to insure that the tools, infrastructure, communication networks, and capacity required to mitigate the impact of high-consequence plant disease outbreaks are such that a reasonable level of crop production is maintained. It is intended to provide a brief primer on the disease, assess the status of critical recovery components, and identify disease management research, extension, and education needs.

Adjuvants, Formulations, and Spraying Systems for Improvement of Mycoherbicides

1996 ◽  
Vol 10 (3) ◽  
pp. 637-644 ◽  
Author(s):  
C. Douglas Boyette ◽  
P. C. Quimby ◽  
A. J. Caesar ◽  
J. L. Birdsall ◽  
W. J. Connick ◽  
...  
Keyword(s):  
United States ◽  
Crop Production ◽  
Pathogenic Fungi ◽  
The United States ◽  
Biological Weed Control ◽  
Plant Pathogenic Fungi ◽  
Row Crops ◽  
Agronomic Crops ◽  
Environmentally Responsible ◽  
Public Pressure

Herbicides are used in the production of almost 100% of agronomic crops in the United States and in most horticultural row crops. By volume, herbicides represent nearly two-thirds of all pesticides used in crop production. However, public pressure is mounting to force industry to develop safer, more environmentally responsible approaches for controlling weeds. Biological weed control with plant pathogenic fungi used as mycoherbicides offers such an approach. But there are several biological and environmental limitations which are inherent to nearly all mycoherbicides which must be overcome before they will be widely acceptable for practical use. Recent advances in adjuvant formulation and delivery systems have been used to overcome some of these limitations, such as lengthy dew requirements, inconsistent efficacy, and limited host ranges. Examples of current research to overcome these limitations will be presented in this review.

scholarly journals Herbicide-resistant weeds in turfgrass: current status and emerging threats

2020 ◽  
Vol 34 (3) ◽  
pp. 424-430
Author(s):  
James T. Brosnan ◽  
Matthew T. Elmore ◽  
Muthukumar V. Bagavathiannan
Keyword(s):  
United States ◽  
Herbicide Resistance ◽  
Production Systems ◽  
The United States ◽  
Target Site ◽  
Current Status ◽  
Weed Species ◽  
Management Tools ◽  
Herbicide Resistant ◽  
Target Site Resistance

AbstractHerbicide-resistant weeds pose a severe threat to sustainable vegetation management in various production systems worldwide. The majority of the herbicide resistance cases reported thus far originate from agronomic production systems where herbicide use is intensive, especially in industrialized countries. Another notable sector with heavy reliance on herbicides for weed control is managed turfgrass systems, particularly golf courses and athletic fields. Intensive use of herbicides, coupled with a lack of tillage and other mechanical tools that are options in agronomic systems, increases the risk of herbicide-resistant weeds evolving in managed turfgrass systems. Among the notable weed species at high risk for evolving resistance under managed turf systems in the United States are annual bluegrass, goosegrass, and crabgrasses. The evolution and spread of multiple herbicide resistance, an emerging threat facing the turfgrass industry, should be addressed with the use of diversified management tools. Target-site resistance has been reported commonly as a mechanism of resistance for many herbicide groups, though non–target site resistance is an emerging concern. Despite the anecdotal evidence of the mounting weed resistance issues in managed turf systems, the lack of systematic and periodic surveys at regional and national scales means that confirmed reports are very limited and sparse. Furthermore, currently available information is widely scattered in the literature. This review provides a concise summary of the current status of herbicide-resistant weeds in managed turfgrass systems in the United States and highlights key emerging threats.

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