Distribution of herbicide-resistant waterhemp (Amaranthus tuberculatus) across row crop production systems in Texas

2019 ◽  
Vol 34 (1) ◽  
pp. 129-139 ◽  
Author(s):  
Vijay Singh ◽  
Russ Garetson ◽  
Josh McGinty ◽  
Peter Dotray ◽  
Gaylon Morgan ◽  
...  
Keyword(s):  
Crop Production ◽  
Production Systems ◽  
Gulf Coast ◽  
Acetolactate Synthase ◽  
Row Crop ◽  
Amaranthus Tuberculatus ◽  
High Level ◽  
Sites Of Action ◽  
Gulf Coast Region ◽  
Coast Region

AbstractWe conducted a survey in the major row-crop production regions of Texas to determine the response of waterhemp to glyphosate (5-enolpyruvylshikimate-3-phosphate synthase [EPSPS] inhibitor), atrazine (photosystem II [PSII] inhibitor), pyrithiobac (acetolactate synthase [ALS] inhibitor), tembotrione (hydroxyphenylpyruvate dioxygenase [HPPD] inhibitor), fomesafen (protoporphyrinogen oxidase [PPO] inhibitor), and dicamba (synthetic auxin). We evaluated 127 accessions for these herbicides. Resistance was confirmed on the basis of plant survival within an accession, and the injury ratings of surviving plants were used to categorize each accession as resistant (<50% injury) or less sensitive (50% to 89% injury). For glyphosate, approximately 27% of all tested accessions were resistant and 20% were less sensitive. The Gulf Coast region had the most glyphosate-resistant accessions (46% of the accessions from this region), followed by the Blacklands region (9%). A dose-response assay of the most resistant waterhemp accession (TX-25) exhibited 17-fold resistance to glyphosate when compared with a susceptible standard. Waterhemp resistance to atrazine also was common in the Gulf Coast region. The accession with the greatest atrazine resistance (TX-31) exhibited 47- and 68-fold resistance to this herbicide when applied POST and PRE, respectively. Widespread resistance to pyrithiobac was observed in waterhemp accessions throughout the Blacklands and Gulf Coast regions. The most resistant accession identified in this study was 61-fold resistant compared with a susceptible standard. No high-level resistance was detected for tembotrione, dicamba, or fomesafen, but high variability in sensitivity to tembotrione and dicamba was observed. One waterhemp accession exhibited reduced sensitivity to fomesafen; the rest were sensitive. Overall, at least two accessions exhibited resistance or reduced sensitivity to herbicides with five different sites of action. The study illustrates the prevalence of multiple herbicide resistance in waterhemp accessions in Texas and emphasizes the need to implement diversified management tactics.

Distribution of herbicide-resistant Palmer amaranth (Amaranthus palmeri) in row crop production systems in Texas

2019 ◽  
Vol 33 (2) ◽  
pp. 355-365 ◽  
Author(s):  
Russ Garetson ◽  
Vijay Singh ◽  
Shilpa Singh ◽  
Peter Dotray ◽  
Muthukumar Bagavathiannan
Keyword(s):  
Crop Production ◽  
Production Systems ◽  
Gulf Coast ◽  
State Level ◽  
Acetolactate Synthase ◽  
Palmer Amaranth ◽  
High Plains ◽  
Row Crop ◽  
Central Texas ◽  
Sites Of Action

AbstractA state-level survey was conducted across major row-crop production regions of Texas to document the level of sensitivity of Palmer amaranth to glyphosate, atrazine, pyrithiobac, tembotrione, fomesafen, and dicamba. Between 137 and 161 Palmer amaranth populations were evaluated for sensitivity to the labelled field rate (1X), and rated as resistant (≤49% injury), less sensitive (50% to 89% injury), or susceptible (90% to 100% injury). For glyphosate, 62%, 19%, 13%, and 13% of the populations from the High Plains, Central Texas, Rio Grande Valley, and Lower Gulf Coast, respectively, were resistant. Resistance to atrazine was more common in Palmer amaranth populations from the High Plains than in other regions, with 16% of the populations resistant and 22% less sensitive. Approximately 90% of the populations from the High Plains that exhibited resistance to atrazine POST also were resistant to atrazine PRE. Of the 160 populations tested for pyrithiobac, approximately 99% were resistant or less sensitive, regardless of the region. No resistance was found to fomesafen, tembotrione, or dicamba. However, 22% of the populations from the High Plains were less sensitive to 1X (93 g ai ha−1) tembotrione, but were killed at 2X, illustrating the background variability in sensitivity to this herbicide. For dicamba, three populations, all from the High Plains, exhibited less sensitivity at the 1X rate (controlled at the 2X rate; 1X = 560 g ae ha−1). One population exhibited multiple resistance to three herbicides with distinct sites of action (SOAs) involving acetolactate synthase, 5-enolpyruvylshikimate-3-phosphate synthase, and photosystem II inhibitors. Palmer amaranth populations exhibited less sensitivity to approximately 15 combinations of herbicides involving up to five SOAs. Dose-response assays conducted on the populations most resistant to glyphosate, pyrithiobac, or atrazine indicated they were 30-, 32-, or 49-fold or more resistant to these herbicides, respectively, compared with a susceptible standard.

scholarly journals The Roles of Labor and Profitability in Choosing a Grazing Strategy for Beef Production in the U.S. Gulf Coast Region

2008 ◽  
Vol 40 (1) ◽  
pp. 301-313 ◽  
Author(s):  
Jeffrey M. Gillespie ◽  
Wayne Wyatt ◽  
Brad Venuto ◽  
David Blouin ◽  
Robert Boucher
Keyword(s):  
Gulf Coast ◽  
Stocking Rate ◽  
Rotational Grazing ◽  
Data Set ◽  
Time And Motion ◽  
Continuous Grazing ◽  
Labor Requirements ◽  
Gulf Coast Region ◽  
Coast Region ◽  
The U.S

Comparisons are made concerning labor required and profitability associated with continuous grazing at three stocking rates and rotational grazing at a high stocking rate in the U.S. Gulf Coast region. A unique data set was collected using a time and motion study method to determine labor requirements. Profits are lowest for low stocking rate–continuous grazing and high stocking rate–rotational grazing. Total labor and labor in three specific categories are greater on per acre and/or per cow bases with rotational-grazing than with continuous-grazing strategies. These results help to explain relatively low adoption rates of rotational grazing in the region.

Three More Voices Papers for This Special Issue of New Solutions—Environmental Justice in the U.S. Gulf Coast Region

2018 ◽  
Vol 28 (4) ◽  
pp. 617-621
Author(s):  
John Sullivan
Keyword(s):  
Environmental Justice ◽  
Gulf Coast ◽  
Special Issue ◽  
Social Fabric ◽  
Economic Disparities ◽  
Climate Risks ◽  
History Of ◽  
Gulf Coast Region ◽  
Coast Region ◽  
The U.S

The U.S. states along the northern shores of the Gulf of Mexico have often been described as America’s Energy Colony. This region is festooned with polluting industries, storage and waste disposal sites for toxic products, and a history of generally lax approaches to environmental public health and enforcement of regulations. This issue of New Solutions includes three interviews of groups and individuals who work for Environmental Justice in the Gulf Coast region. The interviewees provide key insights into the diverse cultural texture and social fabric of the Gulf. Their range of gulf locales and population groups embody different styles of engagement and different relationships to organizing, disseminating health and environmental risk information, and advocating for social and environmental justice. Similarities among their communities in terms of health and economic disparities, climate risks, and vulnerabilities lend credence to the idea of the Gulf as a regional Environmental Justice community.

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