Postemergence herbicides for control of glyphosate-resistant Canada fleabane in corn (original) (raw)
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Journal of Agricultural Science, 2021
A total of seven field studies were conducted in southwestern Ontario from 2018 to 2020 to evaluate S-metolachlor/mesotrione/bicyclopyrone (Acuron Flexi®) and S-metolachlor/atrazine/mesotrione/bicyclopyrone (Acuron®) for the control of glyphosate-resistant (GR) Canada fleabane in corn. Acuron Flexi® and Acuron® applied preplant (PP) controlled GR Canada fleabane 90-97% and 99-100%, respectively. Commonly used PP herbicides in Ontario, dicamba/atrazine + glyphosate and tolpyralate + atrazine + glyphosate controlled GR Canada fleabane 97-99%. Acuron Flexi® and Acuron® applied postemergence (POST) provided 75-92% and 92-99% control of GR Canada fleabane, respectively. Dicamba/atrazine + glyphosate and tolpyralate + atrazine + glyphosate applied POST provided 84-97% and 94-98% control of GR Canada fleabane, respectively. Glyphosate applied POST at 900 ae ha-1 provided only 35-38% control of Canada fleabane in corn. Orthogonal contrasts indicated that herbicides applied PP provided up to...
Canadian Journal of Plant Science, 2014
2014. Canada fleabane (Conyza canadensis) control with preplant applied residual herbicides followed by 2,4-D choline/glyphosate DMA applied postemergence in corn. Can. J. Plant Sci. 94: 1231Á1237. Glyphosate resistant (GR) Canada fleabane (Conyza canadensis) is an extremely problematic weed in no-tillage farming operations. A total of five field trials were conducted over a 2-yr (2012 and 2013) period in Ontario to determine the level of GR Canada fleabane control with a two-pass weed control program of a pre plant (PP) residual herbicide followed by 2,4-D choline/glyphosate dimethylamine (DMA) applied POST. Among residual herbicide treatments evaluated, s-metolachlor (1600 g a.i. ha (1 )'flumetsulam (50 g a.i. ha (1 )'clopyralid (135 g a.e. ha (1 ) provided the most consistent (95Á99%) control across all sites 8 wk after application (WAA). S-metolachlor/atrazine (1800 g a.i. ha (1 ) did not provide effective GR Canada fleabane control (21Á86%) 8 WAA. The preplant residual herbicides followed by 2,4-D choline/glyphosate DMA (1720 g a.e. ha (1 ) POST provided 97Á100% control. Glyphosate (900 g a.e. ha (1 ) applied PP followed by 2,4-D choline/glyphosate DMA POST provided 80Á93% control 8 WAA. The application of 2,4-D choline/glyphosate DMA POST following any PP residual herbicide resulted in 97% or greater control of GR Canada fleabane. Results from this research demonstrate that residual herbicides applied PP followed by 2,4-D choline/glyphosate DMA POST provides excellent control of GR Canada fleabane, and also incorporates different modes of action thereby limiting the selection of resistant weeds. A. et Sikkema, P. H. 2014. Lutte contre la vergerette du Canada (Conyza canadensis) chez le maı¨s par application d'herbicides re´siduels avant la plantation puis de 2,4-D choline/ glyphosate DMA apre`s la levee. Can. J. Plant Sci. 94: 1231Á1237. La vergerette du Canada (Conyza canadensis) re´sistante au glyphosate (RG) s'ave`re extreˆmement proble´matique sur les terres agricoles qui ne sont pas travaille´es. Les auteurs ont effectue´cinq essais sur le terrain pendant deux ans (2012 et 2013), en Ontario, en vue d'e´tablir dans quelle mesure on pourrait lutter contre la vergerette du Canada RG avec un programme de de´sherbage en deux temps, a`savoir l'application d'un herbicide re´siduel de pre´plantation et l'application de 2,4-D choline/glyphosate DMA post-leve´e. Au nombre des herbicides re´siduels teste´s, le me´lange s-me´tolachlor (1600 g de matie`re active par hectare)'flumetsulam (50 g m.a. par hectare)'clopyralid (135 g m.a. par hectare) a donne´le taux de de´sherbage le plus stable (95Á99 %) aux diffe´rents sites, huit semaines apre`s application. Le s-me´tolachlor/atrazine (1800 g m.a. par hectare) ne combat pas efficacement l'adventice (21Á86 %), huit semaines apre`s application. L'application d'herbicides re´siduels avant la plantation suivie d'une application post-leve´e de 2,4-D choline/glyphosate DMA (1720 g m.a. par hectare) de´truit de 97 a`100 % de la vergerette RG. L'application de glyphosate (900 g m.a. par hectare) apre`s la plantation puis de 2,4-D choline/glyphosate DMA apre`s la leve´e de´truit de 80 a`93 % de l'adventice, huit semaines apre`s application. L'application de 2,4-D choline/glyphosate DMA apre`s la leve´e conse´cutivement a`celle d'un herbicide re´siduel quelconque avant la plantation tue 97 % ou plus de l'adventice. Ces re´sultats montrent que l'application d'herbicides re´siduels avant la plantation puis de 2,4-D choline/ glyphosate DMA apre`s la leve´e assure une excellente lutte contre la vergerette du Canada RG. Parce qu'ils agissent diffe´remment, ces herbicides concourent aussi a`retarder l'apparition d'adventices re´sistantes.
Glyphosate-Resistant Canada Fleabane Control in Winter Wheat with Postemergence Herbicides
International Journal of Agronomy
In recent years, there has been a rapid increase in the number of herbicide-resistant weeds, including glyphosate-resistant (GR) biotypes in Ontario, Canada. A total of six field experiments were conducted over a two-year period (2018 and 2019) to determine the control of GR Canada fleabane (Conyza canadensis (L.) Cronq.) with currently available herbicides for winter wheat in Ontario. Winter wheat was not injured with any of the herbicides evaluated. Among herbicides evaluated, pyrasulfotole/bromoxynil (preformulated), 2,4-D ester, halauxifen, fluroxypyr/halauxifen (preformulated) + MCPA, pyrasulfotole/bromoxynil/fluroxypyr (preformulated), pyrasulfotole/bromoxynil/thiencarbazone (preformulated), pyrasulfotole/bromoxynil/thiencarbazone + MCPA, and fluroxypyr/halauxifen + pyroxsulam + MCPA controlled GR Canada fleabane 94–100% at 8 weeks after application (WAA) and reduced density 95–100% and biomass 97–100%. Reduced GR Canada fleabane interference with pyrasulfotole/bromoxynil/thie...
Agricultural Sciences, 2014
Sciences, provides control of GR and other problematic weeds. The objective of this study was to compare single and sequential applications of glyphosate DMA/2,4-D choline for the control of GR Canada fleabane in GR corn. Three single applications of glyphosate (DMA)/2,4-D choline (1720 g•ae•ha −1 ) were evaluated: 1) preplant (PP) applied to Canada fleabane up to 10 cm diameter/height, 2) postplant 1 (POST 1) applied when Canada fleabane was up to 20 cm tall and 3) postplant 2 (POST 2) applied up to 30 cm tall Canada fleabane. Four sequential applications were also examined:1) PP followed by (fb) POST 1, 2) PP fb POST 2, 3) POST 1 fb POST 2 and 4) PP fb POST 1 fb POST 2. The single applications provided 69% -86% control of the GR Canada fleabane while the sequential applications increased control to 92% -100%. Three applications did not provide an increase in control over a sequential two-pass application at 8 weeks after the application (WAA). Results from this research indicate that a sequential 2-pass application of glyphosate DMA/2,4-D choline provided acceptable control of GR Canada fleabane in corn.
Journal of Agricultural Science
Multiple-herbicide-resistant (MHR) Canada fleabane [Conyza canadensis (L.) Cronq.] control has become a major concern for corn producers in Ontario. Postemergence (POST) herbicides are critical for the control of emerged MHR Canada fleabane in corn. A study that consisted of five field experiments was conducted in southwestern Ontario in fields with confirmed MHR Canada fleabane to evaluate various herbicide mixtures applied POST for the control of MHR Canada fleabane in corn. Glyphosate + 2,4-D amine, glyphosate/2,4-D choline, glyphosate + clopyralid, glyphosate + S-metolachlor/mesotrione/bicyclopyrone, glyphosate + tolpyralate + atrazine, glyphosate + dicamba, glyphosate + dicamba/atrazine, glyphosate + S-metolachlor/mesotrione/ atrazine, glyphosate + mesotrione + atrazine, glyphosate + bromoxynil + atrazine, glyphosate + S-metolachlor/ mesotrione/bicyclopyrone/atrazine, glyphosate/S-metolachlor/mesotrione + atrazine, glyphosate/dicamba + tembotrione, glyphosate + tembotrione + br...
Glyphosate resistant (GR) Canada fleabane (horseweed) has quickly spread across southwestern Ontario and is a difficult weed to control in GR crops. Glyphosate dimethylamine (DMA)/2,4-D choline (Enlist Duo?TM Dow AgroSciences LLC), a new herbicide premix developed by Dow Agro Sciences, provides control of GR and other problematic weeds. The objective of this study was to compare single and sequential applications of glyphosate DMA/2,4-D choline for the control of GR Canada fleabane in GR corn. Three single applications of glyphosate (DMA)/2,4-D choline (1720 g·ae·ha-1) were evaluated: 1) preplant (PP) applied to Canada fleabane up to 10 cm diameter/height, 2) postplant 1 (POST 1) applied when Canada fleabane was up to 20 cm tall and 3) postplant 2 (POST 2) applied up to 30 cm tall Canada fleabane. Four sequential applications were also examined:1) PP followed by (fb) POST 1, 2) PP fb POST 2, 3) POST 1 fb POST 2 and 4) PP fb POST 1 fb POST 2. The single applications provided 69%-86% control of the GR Canada fleabane while the sequential applications increased control to 92%-100%. Three applications did not provide an increase in control over a sequential two-pass application at 8 weeks after the application (WAA). Results from this research indicate that a sequential 2-pass application of glyphosate DMA/2,4-D choline provided acceptable control of GR Canada fleabane in corn.
Journal of Agricultural Science
Limited information exists on the efficacy of pyrasulfotole/bromoxynil, fluroxypyr/halauxifen-methyl + MCPA EHE, and clopyralid applied in the fall, spring, or sequentially [fall followed by (fb) spring] for the control of multiple-herbicide-resistant (MHR) Canada fleabane in winter wheat under Ontario environmental conditions. Three field experiments were initiated in the autumn of 2020 and 2021 for a total of 6 site-years to evaluate fall- and spring-applied herbicides and their sequential applications for the control of MHR Canada fleabane in winter wheat in Ontario. Pyrasulfotole/bromoxynil applied in the fall, spring, or sequentially controlled MHR Canada fleabane 83, 99, and 100%, respectively at 8 weeks after the spring application (WAB); the spring and sequential applications provided better control than the fall application. Fluroxypyr/halauxifen + MCPA and clopyralid applied in the fall, spring, or sequentially controlled MHR Canada fleabane 97 to 100% and 99 to 100%, resp...