scholarly journals Herbicide mixtures control glyphosate-resistant kochia (Bassia scoparia) in chemical fallow, but their longevity warrants careful stewardship

2020 ◽  
Author(s):  
Alysha T Torbiak ◽  
Robert Blackshaw ◽  
Randall N Brandt ◽  
Linda M Hall ◽  
Bill Hamman ◽  
...  
Keyword(s):  
Weed Management ◽  
Integrated Weed Management ◽  
Group 14 ◽  
Herbicide Resistant ◽  
Group 4 ◽  
Synthetic Auxins ◽  
Auxin Transport Inhibitor ◽  
Herbicide Mixtures ◽  
Chemical Fallow ◽  
Herbicide Programs

Glyphosate-resistant kochia [Bassia scoparia (L.) A.J. Scott], the first known glyphosate-resistant weed in western Canada, was confirmed initially in chemical fallow fields located in Warner County, Alberta in 2011. Further selection, lack of control, and rampant spread of this biotype contributed to its increased incidence, now present in about 50% of kochia populations sampled in Alberta. In 2014 and 2015, herbicide mixtures were evaluated based on control of glyphosate-resistant and susceptible kochia in chemical fallow fields near Lethbridge and Coalhurst, Alberta. The most consistent control (≥ 80% visual control in all environments with ≥ 80% biomass reduction in 2014) was observed with glyphosate + dicamba (450 + 580 g ae ha-1), glyphosate + dicamba/diflufenzopyr (450 + 150/50 g ai/ae ha-1), glyphosate + saflufenacil (450 + 50 g ai/ae ha-1), and glyphosate + carfentrazone + sulfentrazone (450 + 9 + 105 g ai/ae ha-1). Reduced efficacy was observed for several herbicide mixtures when they were applied to glyphosate-resistant compared with glyphosate-susceptible kochia accessions. Effective modes of action mixed with glyphosate include synthetic auxins (group 4), a combination of a synthetic auxin and an auxin transport inhibitor (group 19), or protoporphyrinogen oxidase inhibitors (group 14). In response to glyphosate-resistant kochia, many farmers in this region shifted their herbicide programs resulting in greater reliance on synthetic auxins; likely contributing to the recent discovery of auxinic herbicide-resistant kochia biotypes in Alberta in 2017. Careful herbicide stewardship is warranted to mitigate further selection of multiple herbicide-resistant kochia, suggesting an important role for integrated weed management.

The Coaxium® Wheat Production System: A New Herbicide-Resistant System for Annual Grass Weed Control and Integrated Weed Management

2021 ◽  
Vol 32 (4) ◽  
pp. 151-157
Author(s):  
Raven A. Bough ◽  
Phillip Westra ◽  
Todd A. Gaines ◽  
Eric P. Westra ◽  
Scott Haley ◽  
...  
Keyword(s):  
Weed Management ◽  
Production System ◽  
Integrated Weed Management ◽  
State University ◽  
Wheat Production ◽  
Colorado State University ◽  
Herbicide Resistant ◽  
System A ◽  
Grass Weed ◽  
Global Food

The authors discuss the importance of wheat as a global food source and describe a novel multi-institutional, public-private partnership between Colorado State University, the Colorado Wheat Research Foundation, and private chemical and seed companies that resulted in the development of a new herbicide-resistant wheat production system.

scholarly journals Herbicide-resistant crops in resistant weed management : An industrial perspective

2005 ◽  
Vol 75 (4) ◽  
pp. 79-84 ◽  
Author(s):  
D. Shaner
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Wild Species ◽  
Integrated Weed Management ◽  
Herbicide Resistant ◽  
Resistant Varieties ◽  
Selection Of

Some of the first products of biotechnology to reach the marketplace have been herbicide-resistant crops. Industry sees the development of herbicide-resistant varieties as a way to increase the availability of proven herbicides for a broader range of crops. However, the development of herbicide- resistant crops requires special attention to potential environmental questions such as herbicide usage, selection of resistant weed biotypes and spread of resistance from the resistant crop to wild species. Industry is actively addressing these concerns during the process of development. Proper development and use of herbicide-resistant crops in integrated weed management programs will provide farmers with increased flexibility, efficiency, and decreased cost in their weed control practices without increasing the risk of herbicide-resistant weeds. Furthermore, herbicide-resistant crops should prove to be valuable tools in managing herbicide- resistant weeds.

Weed Problems in Uruguayan Agriculture: Evolution and Current Situation

2021 ◽  
Vol 32 (5) ◽  
pp. 203-207
Author(s):  
M. Alejandro Garcia ◽  
Lucia V. Meneses ◽  
Tiago Edu Kaspary
Keyword(s):  
Weed Management ◽  
Agricultural Production ◽  
Production Systems ◽  
Integrated Weed Management ◽  
Zero Tillage ◽  
Weed Species ◽  
Management Tools ◽  
Herbicide Resistant ◽  
Species Frequencies ◽  
Agricultural Production Systems

Uruguayan agriculture has undergone dramatic changes in the last 50 years driven by the adoption of new agricultural production systems that incorporate zero tillage and herbicide resistant crops. This has resulted in a shift in weed species frequencies and the dispersion of introduced herbicide resistant weed populations. Finally, integrated weed management tools are being developed by research and extension services to manage herbicide-resistant (HR) weeds better and to reduce environmental impact of herbicides.

Herbicide Timing and Rate Effects on Weed Management in Three Herbicide-Resistant Canola Systems

2004 ◽  
Vol 18 (4) ◽  
pp. 1006-1012 ◽  
Author(s):  
K. Neil Harker ◽  
George W. Clayton ◽  
John T. O'Donovan ◽  
Robert E. Blackshaw ◽  
F. Craig Stevenson
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Management Practices ◽  
Integrated Weed Management ◽  
Weed Biomass ◽  
Herbicide Resistant ◽  
Leaf Stage ◽  
Rate Effects ◽  
Herbicide Timing ◽  
Weed Removal

Herbicide-resistant canola dominates the canola market in Canada. A multiyear field experiment was conducted at three locations to investigate the effect of time of weed removal (two-, four-, or six-leaf canola) and herbicide rate (50 or 100% recommended) in three herbicide-resistant canola systems. Weeds were controlled in glufosinate-resistant canola (GLU) with glufosinate, in glyphosate-resistant canola (GLY) with glyphosate, and in imidazolinone-resistant canola (IMI) with a 50:50 mixture of imazamox and imazethapyr. Canola yields were similar among the three canola cultivar–herbicide systems. Yields were not influenced by 50 vs. 100% herbicide rates. Timing of weed removal had the greatest effect on canola yield, with weed removal at the four-leaf stage giving the highest yields in most cases. Percent dockage was often greater for GLU and IMI than for GLY. In comparison with the other treatments, dockage levels doubled for GLU after application at 50% herbicide rates. The consistency of monocot weed control was usually greater for GLY than for GLU or IMI systems. However, weed biomass data revealed no differences in dicot weed control consistency between IMI and GLY systems. Greater dockage and weed biomass variability after weed removal at the six-leaf stage or after low herbicide rates suggests higher weed seed production, which could constrain the adoption of integrated weed management practices in subsequent years.

scholarly journals Effective Preemergence and Postemergence Herbicide Programs for Kochia Control

2015 ◽  
Vol 29 (1) ◽  
pp. 24-34 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha
Keyword(s):  
Field Experiments ◽  
Agricultural Research ◽  
Residual Activity ◽  
Acetolactate Synthase ◽  
Test Site ◽  
Herbicide Resistant ◽  
Greenhouse Study ◽  
Chemical Fallow ◽  
Herbicide Programs ◽  
Crop Competition

Field experiments were conducted in 2011 through 2013 at the MSU Southern Agricultural Research Center near Huntley, MT, to evaluate the effectiveness of various PRE and POST herbicide programs for kochia control in the absence of a crop. PRE herbicides labeled for corn, grain sorghum, soybean, wheat/barley, and/or in chemical fallow were applied at recommended field-use rates. Acetochlor + atrazine,S-metolachlor + atrazine + mesotrione, and sulfentrazone applied PRE provided ≥91% control of kochia at 12 wk after treatment (WAT). Metribuzin, metribuzin + linuron, and pyroxasulfone + atrazine PRE provided 82% control at 12 WAT. PRE control with acetochlor + flumetsulam + clopyralid, pyroxasulfone alone, and saflufenacil + 2,4-D was ≤23% at 12 WAT. Paraquat + atrazine, paraquat + linuron, and paraquat + metribuzin controlled kochia ≥98% at 5 WAT. POST control with bromoxynil + fluroxypyr, paraquat, tembotrione + atrazine, and topramezone + atrazine treatments averaged 84% at 5 WAT, and did not differ from glyphosate. Control with POST-applied bromoxynil + pyrasulfotole, dicamba, diflufenzopyr + dicamba + 2,4-D, saflufenacil, saflufenacil + 2,4-D, saflufenacil + linuron was 67 to 78% at 5 WAT. Because of the presence of kochia resistant to acetolactate synthase-inhibiting herbicides at the test site, cloransulam-methyl was not a viable option for kochia control. In a separate greenhouse study, kochia accessions showed differential response to the POST herbicides (labeled for corn or soybean) tested. Tembotrione + atrazine, topramezone + atrazine, lactofen, or fomesafen effectively controlled the glyphosate-resistant kochia accession tested. Growers should utilize these effective PRE- or POST-applied herbicide premixes or tank mixtures (multiple modes of action) to control herbicide-resistant kochia accessions in the field. PRE herbicides with 8 wk of soil-residual activity on kochia would be acceptable if crop competition were present; however, a follow-up herbicide application may be needed to obtain season-long kochia control in the absence of crop competition.

scholarly journals A New Approach to Weed Management to Mitigate Herbicide Resistance in Argentina

Weed Science ◽  
2016 ◽  
Vol 64 (SP1) ◽  
pp. 641-648 ◽  
Author(s):  
Claudio Rubione ◽  
Sarah M. Ward
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Integrated Weed Management ◽  
National Committee ◽  
Weed Species ◽  
Corn Production ◽  
Public And Private ◽  
Herbicide Resistant ◽  
Crop Varieties ◽  
Export Taxes

The evolution of herbicide-resistant weeds is a major concern in the corn- and soybean-producing Pampas region of Argentina, where growers predominantly plant glyphosate-resistant crop varieties and depend heavily on glyphosate for weed control. Currently, 16 weed species in Argentina are resistant to one or more of three different herbicide mechanisms of action, and resistant weed populations continue to increase, posing a serious threat to agricultural production. Implementation of integrated weed management to address herbicide resistance faces significant barriers in Argentina, especially current land ownership and rental patterns in the Pampas. More than 60% of Pampas cropland is rented to tenants for periods that rarely exceed 1 yr, resulting in crop rotation being largely abandoned, and crop export taxes and quotas have further discouraged wheat and corn production in favor of continuous soybean production. In this paper we discuss ways to facilitate new approaches to weed management in Argentina, including legal and economic reforms and the formation of a national committee of stakeholders from public and private agricultural sectors.

Suppression of Glyphosate-resistant Canada Fleabane (Conyza canadensis) in Corn with Cover Crops Seeded after Wheat Harvest the Previous Year

2018 ◽  
Vol 32 (3) ◽  
pp. 244-250 ◽  
Author(s):  
Taïga B. Cholette ◽  
Nader Soltani ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
Peter H. Sikkema
Keyword(s):  
Cover Crops ◽  
Weed Management ◽  
Cover Crop ◽  
Management Strategies ◽  
Late Summer ◽  
Growing Season ◽  
Integrated Weed Management ◽  
Crop Species ◽  
Herbicide Resistant ◽  
Crimson Clover

AbstractGlyphosate-resistant (GR) and multiple herbicide–resistant (groups 2 and 9) Canada fleabane have been confirmed in 30 and 23 counties in Ontario, respectively. The widespread incidence of herbicide-resistant Canada fleabane highlights the importance of developing integrated weed management strategies. One strategy is to suppress Canada fleabane using cover crops. Seventeen different cover crop monocultures or polycultures were seeded after winter wheat harvest in late summer to determine GR Canada fleabane suppression in corn grown the following growing season. All cover crop treatments seeded after wheat harvest suppressed GR Canada fleabane in corn the following year. At 4 wk after cover crop emergence (WAE), estimated cover crop ground cover ranged from 31% to 68%, a density of 124 to 638 plants m–2, and a range of biomass from 29 to 109 g m–2, depending on cover crop species. All of the cover crop treatments suppressed GR Canada fleabane in corn grown the following growing season from May to September compared to the no cover crop control. Among treatments evaluated, annual ryegrass (ARG), crimson clover (CC)/ARG, oilseed radish (OSR)/CC/ARG, and OSR/CC/cereal rye (CR) were the best treatments for the suppression of GR Canada fleabane in corn. ARG alone or in combination with CC provided the most consistent GR Canada fleabane suppression, density reduction, and biomass reduction in corn. Grain corn yields were not affected by the use of the cover crops evaluated for Canada fleabane suppression.

Effectiveness of Herbicides for Control of Hairy Vetch (Vicia villosa) in Winter Wheat

2015 ◽  
Vol 29 (3) ◽  
pp. 509-518 ◽  
Author(s):  
William S. Curran ◽  
John M. Wallace ◽  
Steven Mirsky ◽  
Benjamin Crockett
Keyword(s):  
Winter Wheat ◽  
Weed Management ◽  
Acetolactate Synthase ◽  
Oxidase Inhibitor ◽  
Management Program ◽  
Integrated Weed Management ◽  
Hairy Vetch ◽  
Synthetic Auxins ◽  
Als Inhibitors ◽  
Tribenuron Methyl

A field experiment was conducted in 2009–2010 at Pennsylvania and Maryland locations, and repeated it in 2010–2011 to test the effectiveness of POST-applied herbicides at fall and spring timings on seeded hairy vetch in winter wheat. A total of 16 herbicide treatment combinations was tested that included synthetic auxins, acetolactate synthase (ALS) inhibitors, and a protoporphyrinogen oxidase inhibitor. Spring applications tended to be more effective than fall applications. Among synthetic auxins, clopyralid (105 g ae ha−1) and treatments containing dicamba (140 g ae ha−1) were effective at both timings, resulting in greater than 90% hairy vetch control at wheat harvest. Pyroxsulam and prosulfuron applied at 18 g ai ha−1 provided the most effective hairy vetch control (> 90%) at both application timings among ALS inhibitors. Spring applications of several herbicides provided moderate (> 80%) to high (> 90%) levels of hairy vetch control, including: 2,4-D amine (140 g ae ha−1), mesosulfuron-methyl (15 g ai ha−1), tribenuron-methyl (13 g ai ha−1), and thifensulfuron/tribenuron-methyl treatments (16 and 32 g ai ha−1). Winter wheat injury was evaluated, but symptoms were negligible for most treatments. Winter wheat yields declined with increasing hairy vetch biomass. Fall herbicides may be prioritized to reduce hairy vetch competition during the fall and early spring growing season. Our research has established that several synthetic auxin and ALS-inhibiting herbicides, applied POST in fall or spring, can be safely used in winter wheat to control hairy vetch in an integrated weed management program.

Evaluation of Herbicide Programs for Use in a 2,4-D–Resistant Soybean Technology for Control of Glyphosate-Resistant Palmer Amaranth (Amaranthus palmeri)

2016 ◽  
Vol 30 (2) ◽  
pp. 366-376 ◽  
Author(s):  
M. Ryan Miller ◽  
Jason K. Norsworthy
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Palmer Amaranth ◽  
Integrated Weed Management ◽  
Amaranthus Palmeri ◽  
Early Season ◽  
Fully Integrated ◽  
Soil Seedbank ◽  
High Level ◽  
Herbicide Programs

Two separate field experiments were conducted over a 2-yr period in Fayetteville, AR, during 2012 and 2013 to (1) evaluate POST herbicide programs utilizing a premixture of dimethylamine (DMA) salt of glyphosate + choline salt of 2,4-D in a soybean line resistant to 2,4-D, glyphosate, and glufosinate and (2) determine efficacy of herbicide programs that begin with PRE residual herbicides followed by POST applications of 2,4-D choline + glyphosate DMA on glyphosate-resistant Palmer amaranth. In the first experiment, POST applications alone that incorporated the use of residual herbicides with the glyphosate + 2,4-D premixture provided 93 to 99% control of Palmer amaranth at the end of the season. In the second experiment, the use of flumioxazin, flumioxazin + chlorimuron methyl, S-metolachlor + fomesafen, or sulfentrazone + chloransulam applied PRE provided 94 to 98% early-season Palmer amaranth control. Early-season control helped maintain a high level of Palmer amaranth control throughout the growing season, in turn resulting in fewer reproductive Palmer amaranth plants present at soybean harvest compared to most other treatments. Although no differences in soybean yield were observed among treated plots, it was evident that herbicide programs should begin with PRE residual herbicides followed by POST applications of glyphosate + 2,4-D mixed with residual herbicides to minimize late-season escapes and reduce the likelihood of contributions to the soil seedbank. Dependent upon management decisions, the best stewardship of this technology will likely rely on the use multiple effective mechanisms of action incorporated into a fully integrated weed management system.

Multiple-resistant waterhemp control in herbicide-resistant 3 (HT3) soybean

2020 ◽  
Vol 100 (6) ◽  
pp. 692-696
Author(s):  
Nader Soltani ◽  
Lynette R. Brown ◽  
Peter H. Sikkema
Keyword(s):  
Weed Management ◽  
Growth Stage ◽  
Field Experiments ◽  
Management Option ◽  
Soybean Yield ◽  
Herbicide Resistant ◽  
Herbicide Programs

Herbicide-resistant (HR) crops, specifically glyphosate-, glufosinate-, and dicamba-resistant (HT3) soybean, will offer producers a new weed management option for the control of some HR weeds in soybean. Four field experiments were conducted near Cottam and on Walpole Island, ON, Canada, during 2017 and 2018 to assess the control of multiple-resistant (MR) waterhemp (herbicide groups 2, 5, and 9) in HT3 soybean treated with various herbicide programs. Pyroxasulfone/flumioxazin, flumioxazin plus metribuzin, or S-metolachlor/metribuzin applied preemergence (PRE) and followed by (fb) glyphosate postemergence (POST) controlled MR waterhemp at 94%, 66%, and 78%, respectively, in early September. Pyroxasulfone/flumioxazin, flumioxazin plus metribuzin, or S-metolachlor/metribuzin applied PRE controlled MR waterhemp 86%–97% when fb glufosinate POST; 100% when fb glyphosate plus dicamba POST; 99%–100% when fb glufosinate plus dicamba POST; and 100% when fb glyphosate plus dicamba POST and fb glufosinate POST2 (before the R2 soybean growth stage) in early September. Reduced MR waterhemp interference with all herbicide programs resulted in an increase in HT3 soybean yield (up to 59%) relative to the weedy control. Results indicate that pyroxasulfone/flumioxazin, flumioxazin plus metribuzin, or S-metolachlor/metribuzin applied PRE fb glufosinate POST, glyphosate plus dicamba POST, glufosinate plus dicamba POST, or glyphosate plus dicamba POST fb glufosinate POST2 provides similar and excellent season-long control of MR waterhemp in HT3 soybean.

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