Biologically effective rate of metribuzin for glyphosate-resistant Canada fleabane control in soybean (original) (raw)
Canadian Journal of Plant Science, 2016
The future release of 'Balance GT' soybean, which is resistant to isoxaflutole and glyphosate, opens up the possibility for control of glyphosate-resistant (GR) Canada fleabane using HPPD-inhibiting herbicides (Group 27) in soybean. Field trials were conducted over two years to evaluate the dose response of an isoxaflutole plus metribuzin tank mix, as well as each chemical applied alone, to assess their response using Flint's adaptation of Colby's equation. Factorial experiments were performed in growth room and greenhouse environments to assess isoxaflutole versus glyphosate, isoxaflutole versus metribuzin, and isoxaflutole plus metribuzin versus glyphosate. Tank mixes of isoxaflutole plus metribuzin in a 1:4 ratio provided 80% control of GR Canada fleabane at a dose range between 420 (84 + 336) and 611 (122 + 489) g a.i. ha 1 at 8 WAA (weeks after application). Tank mixes achieved an 80% reduction in biomass at a dose range between 498 and 738 g a.i. ha 1 , while 80% reduction in density was obtained with doses from 96 to 423 g a.i. ha 1 , 8 WAA. With glyphosate as a constant tank partner, field treatments of isoxaflutole plus metribuzin were mostly synergistic with some analyses showing an additive response. When tested in the growth room, isoxaflutole plus glyphosate tank mixes indicate additivity in the majority of treatments on glyphosate-susceptible (GS) fleabane.
Control of glyphosate resistant Canada fleabane in soybean with preplant herbicides
Canadian Journal of Plant Science, 2016
Thirteen herbicide tankmixes were evaluated during 2013-2015 for control of glyphosate resistant (GR) Canada fleabane in soybean. Glyphosate+saflufenacil+smetolachlor/metribuzin, glyphosate+amitrole and glyphosate+metribuzin were the most efficacious and controlled GR Canada fleabane 86 to 92%, reduced density 98 to 99% and reduced aboveground biomass 96 to 97%.
Agronomy
Glyphosate + dicamba has provided variable glyphosate-resistant Canada fleabane (GRCF) control in glyphosate/dicamba-resistant (GDR) soybean. Previous research has indicated improved GRCF control when a third herbicide was added to glyphosate + dicamba, though research is limited. The objective of this research was to ascertain if the level and consistency of GRCF control can be improved when adding tiafenacil, metribuzin, bromoxynil, pyraflufen-ethyl/2,4-D, 2,4-D ester, halauxifen-methyl or saflufenacil to glyphosate + dicamba applied preplant (PP) in GDR soybean. Four field trials were conducted in 2020 and 2021 in commercial fields in southwestern Ontario, Canada. Glyphosate + dicamba controlled GRCF 57, 93 and 94% at 2, 4 and 8 WAA, respectively. Adding bromoxynil to glyphosate + dicamba improved GRCF control from 57 to 77% at 2 WAA; adding saflufenacil to glyphosate + dicamba improved GRCF control from 57 to 92, 93 to 99, and 94 to 99% at 2, 4 and 8 WAA, respectively. All three...
Glyphosate-Resistant Canada Fleabane Control with Three-Way Herbicide Tankmixes in Soybean
American Journal of Plant Sciences, 2020
Eight field trials (2 in 2016, 3 in 2017, 3 in 2018) were conducted in farmers' fields with heavy infestations of GR Conyza canadensis (Canada fleabane, horseweed or marestail) to evaluate glyphosate (900 g ae ha −1) plus saflufenacil (25 g ai ha −1), 2,4-D ester (500 g ai ha −1) or paraquat (1100 g ai ha −1) applied preplant (PP) as 2-way tankmixes, or in 3-way tankmixes with sulfentrazone (140 g ai ha −1), flumioxazin (107 g ai ha −1) or metribuzin (400 g ai ha −1) for the glyphosate-resistant (GR) C. canadensis control in GR soybean. Glyphosate plus saflufenacil applied PP controlled GR C. canadensis as much as 90%. The addition of sulfentrazone, flumioxazin or metribuzin to the tankmix provided as much as 93%, 96% and 97% control of GR C. canadensis, respectively. Glyphosate plus 2,4-D ester applied PP provided as much as 59% control of GR C. canadensis. The addition of sulfentrazone, flumioxazin or metribuzin to the tankmix provided as much as 60%, 59% and 91% control of GR C. canadensis, respectively. Glyphosate plus paraquat applied PP provided as much as 85% control of GR C. canadensis. The addition of sulfentrazone, flumioxazin or metribuzin to the tankmix provided as much as 88%, 89% and 98% control of GR C. canadensis, respectively. Density and biomass reductions of GR C. canadensis with herbicides evaluated followed the same pattern as weed control evaluations. GR C. canadensis interference reduced soybean yield 66%. Reduced GR C. canadensis interference with the preplant herbicides evaluated provided soybean yield similar to the weed-free control. Results from this study show that glyphosate plus saflufenacil, glyphosate plus 2,4-D ester or glyphosate plus paraquat tankmixed with metribuzin can provide effective control of GR C. canadensis in GR soybean.
Journal of agricultural science, 2023
During 2021 and 2022, four experiments were conducted to ascertain the sensitivity of azuki bean to saflufenacil herbicide mixtures, and five experiments were conducted to determine the control of multiple herbicide-resistant (MHR) Canada fleabane with various saflufenacil herbicide mixtures applied preplant (PP) in soybean at various locations in southwestern Ontario, Canada. At 1, 2, 4, and 8 weeks after emergence (WAE), glyphosate + saflufenacil caused 2-5% azuki bean injury. The addition of metribuzin, bromoxynil, halauxifen-methyl, or 2,4-D ester caused 2-7%, 2-4%, 4-9%, and 2-4% azuki bean injury, respectively. Glyphosate + saflufenacil + bromoxynil plus either metribuzin, halauxifen-methyl, or 2,4-D ester caused 3-7%, 5-11%, and 3-6% azuki bean injury, respectively. Saflufenacil mixtures evaluated had no adverse effect on azuki bean stand, biomass m-1 , biomass plant-1 , height, seed moisture content, or yield. At 4 and 8 weeks after application (WAA), glyphosate + saflufenacil control MHR Canada fleabane 93 and 87%, respectively; there was no improvement in MHR Canada fleabane control with the glyphosate + saflufenacil mixtures evaluated. At 8 WAA, saflufenacil herbicide mixtures evaluated reduced MHR Canada fleabane density 43-95% and biomass 47-96%; differences were not statistically significant. MHR Canada fleabane interference reduced soybean yield 50%; however, reduced MHR Canada fleabane interference with all glyphosate + saflufenacil mixtures evaluated resulted in soybean yield that was similar to the weed-free control. This study concludes that saflufenacil herbicide mixtures evaluated have the potential to be used for the control MHR Canada fleabane in azuki bean.
Weed Science, 2016
Field studies were conducted in 2005 and 2006 to determine the most effective chemical options within three individual herbicide-based burndown programs, glyphosate, paraquat and glufosinate, for controlling glyphosate-resistant horseweed in Mississippi. Burndown treatments were applied April 5, 2005 and March 15, 2006 to horseweed plants 15 to 30 cm in height. Glyphosate at 0.86 kg ae/ha alone provided 60 to 65% horseweed control 4 wk after treatment (WAT). Control 4 WAT ranged from 73 to 74% when the glyphosate rate was increased to 1.25 kg/ha. Glyphosate at 0.86 kg/ha applied in combination with 2,4-D at 0.84 kg ae/ha or dicamba at 0.28 ae/ha maximized control of horseweed ($ 90%) 4 WAT and soybean yield. Horseweed control 4 WAT with paraquat alone at 0.84 kg ai/ha ranged from 55 to 63% and control did not improve by increasing the rate to 0.98 kg/ha. Addition of 2,4-D or dicamba to paraquat maximized horseweed control both years (78 to 89%), whereas soybean yield was maximized with addition of dicamba or metribuzin at 0.42 kg ai/ha. Glufosinate applied alone at 0.47 kg ai/ha resulted in at least 88% control of horseweed and maximized soybean yield. Results indicate that effective management of glyphosate-resistant horseweed can be obtained in glyphosate-resistant soybean in glyphosate-, paraquat-, and glufosinate-based preplant weed control programs.
Journal of Agricultural Science, 2021
Glyphosate-resistant (GR) Canada fleabane (Erigeron canadensis L.) is a problematic weed in soybean. Bromoxynil-based tankmixes provide control of GR Canada fleabane in monocot crops; however, there is limited research on preplant (PP) applications in soybean. The objective of this study was to determine the best third tankmix partner with glyphosate plus bromoxynil applied PP to improve the level and consistency of GR Canada fleabane control in soybean. Four field trials were conducted over a two-year (2020, 2021) period. Glyphosate plus bromoxynil controlled GR Canada fleabane 52, 58, and 69% at 2, 4, and 8 weeks after application (WAA) respectively. The addition of saflufenacil to glyphosate plus bromoxynil improved GR Canada fleabane control 39% at 2 WAA and the addition of dicamba to glyphosate plus bromoxynil improved GR Canada fleabane control 39 and 29% at 4 and 8 WAA, respectively. The addition of bromoxynil to glyphosate plus 2,4-D ester or dicamba improved GR Canada fleab...
Canadian Journal of Plant Science, 2013
Byker, H. P., Soltani, N., Robinson, D. E., Tardif, F. J., Lawton, M. B. and Sikkema, P. H. 2013. Control of glyphosate-resistant Canada fleabane [ Conyza canadensis (L.) Cronq.] with preplant herbicide tankmixes in soybean [ Glycine max . (L). Merr.]. Can. J. Plant Sci. 93: 659–667. Glyphosate previously provided excellent control of Canada fleabane; however, with the evolution of glyphosate-resistant (GR) Canada fleabane in Ontario, alternative herbicides must be identified for control of this weed in soybean. The objective of this study was to identify preplant herbicide tankmixes that provide effective control of GR Canada fleabane. A total of 12 field trials were completed over a 2-yr period (2011, 2012) in fields previously confirmed with GR Canada fleabane. Preplant tankmixes of glyphosate (900 g a.e. ha−1) plus saflufenacil (25 g a.i. ha−1) or saflufenacil/dimethenamid-p (245 g a.i. ha−1) provided greater than 87% control 4 wk after application (WAA) across all sites. Glypho...
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...
Glyphosate-resistant soybeans yield in function of glyphosate salts, doses and stadium phenological
Bioscience Journal, 2020
Given the importance of soybean to the global economy and as a food source, improving crop management techniques is integral to obtaining higher yields. As such, this study aimed to assess the yield of soybean cultivars as a function of different glyphosate salt formulations, doses and application times. Two field experiments were conducted simultaneously using a randomized block design and 3x4x2 factorial scheme, with three repetitions. Factor A consisted of three glyphosate formulations: isopropylamine salt (Roundup Original®), ammonium salt (Roundup WG®), and potassium salt (Zapp Qi®), factor B four application times: 0, 14, 28, 42 days after planting (DAP), and factor C two doses: the recommended dose of 720 grams of acid equivalent per hectare and twice that (1440 grams of acid equivalent per hectare). There was no difference between the glyphosate salts for the BMX Ativa RR® cultivar, but yields of BMX Apolo RR® submitted to ammonium salt were 28% higher than those recorded fo...
Co-application of glyphosate plus an insecticide or fungicide in glyphosate-resistant soybean
Canadian Journal of Plant Science, 2012
Soltani, N., Shropshire, C. and Sikkema, P. H. 2012. Co-application of glyphosate plus an insecticide or fungicide in glyphosate-resistant soybean. Can. J. Plant Sci. 92: 297–302. Six field trials were conducted from 2008 to 2010 in Ontario to evaluate soybean injury and weed control efficacy with glyphosate tankmixed with various insecticides or fungicides. There was minimal visual injury (less than 4%) in glyphosate-resistant soybean and no adverse effect on soybean height and yield when cyhalothrin-lambda (Matador®), dimethoate (Lagon®), imidacloprid/deltamethrin (Concept®), spirotetramat (Movento®), pyraclostrobin (Headline®), azoxystrobin (Quadris®), propiconazole (Tilt®), azoxystrobin/propiconazole (Quilt®), tebuconazole (Folicur®) and trifloxystrobin/propiconazole (Stratego®) were tankmixed with glyphosate. Velvetleaf, pigweed species, common ragweed, common lambsquarters and green foxtail control ranged from 91–97, 94–99, 92–99, 80–94 and 98–100%, respectively. However, ther...
Postemergence herbicides for control of glyphosate-resistant Canada fleabane in corn
Canadian Journal of Plant Science
Short Title: Glyphosate-resistant Canada fleabane control in corn Postemergence herbicides were evaluated for glyphosate-resistant Canada fleabane control in corn (Zea mays L.) from 2013 to 2015. By 8 wk after treatment, dicamba/atrazine (96% control), dicamba (95% control), bromoxynil + atrazine (93% control), dicamba/diflufenzopyr (90% control), and tembotrione/thiencarbaxone-methyl + dicamba (85% control) reduced population density and aboveground biomass to levels equivalent to the weed-free control.
American Journal of Plant Sciences, 2020
Two studies, each consisting of six field experiments were conducted in growers' fields in 2018 and 2019 to determine the optimal herbicide tankmixes, applied preplant (PP) for the control of glyphosate-resistant (GR) marestail in 1) identity-preserved and glyphosate-resistant soybean (Study 1) and, 2) glyphosate/dicamba-resistant soybean (Study 2). There was no significant injury in soybean with the PP herbicides evaluated in both studies. In Study 1, at 8 weeks after treatment (WAA), glyphosate + saflufenacil, glyphosate + 2,4-D ester, glyphosate + pyraflufen/2,4-D, glyphosate +, 4-D choline or glyphosate + halauxifen-methyl, applied PP, controlled GR marestail 93%, 58%, 60%, 67% and 71%, respectively. The addition of metribuzin to the tankmixes of glyphosate + saflufenacil, 2,4-D ester and pyraflufen/2,4-D increased the control to 98%, 91% and 95%, respectively. The addition of metribuzin + chlorimuron-ethyl to 2,4-D choline/glyphosate and glyphosate + halauxifen-methyl increased the control to 94% and 93%, respectively. In Study 2, at 8 WAA, glyphosate/dicamba, applied PP, controlled GR marestail 89% in glyphosate/dicamba-resistant soybean. The addition of metribuzin or saflufenacil to glyphosate/dicamba controlled GR marestail 86% and 97%, respectively. At 8 WAA, S-metolachlor/dicamba controlled GR marestail 83%. The addition of metribuzin or saflufenacil to the above premix controlled GR marestail 87% and 97%, respectively. Density and biomass reductions were similar to visible control. GR marestail interference reduced soybean yield 60% and 53% in Study 1 and 2, respectively. Reduced GR marestail interference with all the herbicide treatments evaluated in both studies resulted in soybean yield that was similar to the weed-free control.
Weed Technology, 2012
Eight field studies were conducted over a 3-yr period from 2008 to 2010 in Ridgetown, Ontario, Canada, to determine the cumulative stress caused by simulated glyphosate spray drift followed by an in-crop application of metribuzin in processing tomato. As the simulated glyphosate spray drift rate increased so did the degree of injury to the tomatoes. At a simulated spray drift rate of 22.5 g ae ha−1 (2.5% of the recommended glyphosate field rate), a 23% decrease in red tomato yield was observed. Yield reductions increased to 88% of the control when 180 g ae ha−1 glyphosate (20% of the recommended field rate) was applied. Similarly when simulated spray drift rates were followed 3 to 5 d later with an in-crop application of metribuzin at 250 g ai ha−1, tomato yields decreased by 22 to 85% depending on glyphosate rate applied. A transient synergistic interaction was observed only when 22.5 g ae ha−1 glyphosate was followed by metribuzin. The synergistic response was no longer evident by...
Agricultural Sciences, 2014
The 2,4-D choline/glyphosate DMA formulation has reduced drift and volatility compared to the amine or ester formulation of 2,4-D and therefore is advantageous compared to a tank mix of 2,4-D amine or ester with glyphosate. The objective of this research was to compare the control of glyphosate susceptible and glyphosate resistant Canada fleabane with 2,4-D choline/glyphosate DMA with 2,4-D amine, glyphosate, and a tank mix of 2,4-D amine and glyphosate. Ten rates of 2,4-D amine (0 -6708 g•ae•ha⁻¹), glyphosate (0 -7052 g•ae•ha⁻¹), a tank mix of glyphosate plus 2,4-D amine (0 -7052 g•ae•ha⁻¹ + 0 -6708), and 2,4-D choline/glyphosate DMA (0 -13760 g•ae•ha⁻¹) were examined in the greenhouse for the control of two susceptible (GS) and two resistant to glyphosate (GR) Canada fleabane biotypes. The tank mix of 2,4-D amine plus glyphosate and 2,4-D choline/glyphosate DMA provided equivalent control of the GR Canada fleabane biotypes at 35 days after the application (DAA). The 2,4-D choline/glyphosate DMA treatment was more efficacious than the tank mix on the GS biotypes. Glyphosate (880 g•ae•ha⁻¹) provided 50% and 100% control of the resistant and susceptible biotypes, respectively. The 2,4-D choline/glyphosate DMA formulation and the tankmix of 2,4-D amine and glyphosate provided similar control of GR Canada fleabane.
AI Publication, 2019
Soybean (Glycine max (L.) Merrill) is one of the most important crops in the world economy. With the official release of glyphosate- resistant transgenic soybeans in 2005, profound changes in weed management systems are occurring. The objective of the present work was to evaluate the physiological effects caused by application of EPSPS inhibitor herbicide applied in isolation and in mixture with Protox inhibitor herbicide in RR soybean plants. The experiment was conducted in the experimental area of the Federal University of Tocantins, Gurupi University Campus. The material used for planting was the cultivar SYNGENTA 1183 RR. The experimental design was a completely randomized (DIC) arranged in factorial scheme 8x6 + 1, being 8 doses of herbicides in different concentrations (4 doses of glyphosate in the dosages 480 gia ha- 1; 980 gia ha-1; 1140 gia ha- 1; 1920 gia ha-1 plus four mixing doses of the glyphosate + flumioxazin herbicides at dosages of 480 + 20, 980 + 20, 1140 + 20 and 1920 + 20 gia ha-1) and the control (no application). After the application of the herbicides, 6 physiological evaluations were carried out, the first 5 days after the application and the others of 7 in 7 DAA. The parameters evaluated were: height, diameter, phytotoxicity, photosynthesis, stomatal conductance, internal carbon and transpiration The isolated glyphosate interfered in the growth of the plants with a reduction in height in relation to the control, with increasing doses. However in the mixture there was a significant difference and in the mixture of glyphosate + flumioxazin herbicides, there was reduction in the physiological parameters.
Glyphosate Affects Seed Composition in Glyphosate-Resistant Soybean
Journal of Agricultural and Food Chemistry, 2010
The cultivation of glyphosate-resistant (GR) soybeans has continuously increased worldwide in recent years mainly due to the importance of glyphosate in current weed management systems. However, not much has been done to understand eventual effects of glyphosate application on GR soybean physiology, especially those related to seed composition with potential effects on human health. Two experiments were conducted to evaluate the effects of glyphosate application on GR soybeans compared with its near-isogenic non-GR parental lines. Results of the first experiment showed that glyphosate application resulted in significant decreases in shoot nutrient concentrations, photosynthetic parameters, and biomass production. Similar trends were observed for the second experiment, although glyphosate application significantly altered seed nutrient concentrations and polyunsaturated fatty acid percentages. Glyphosate resulted in significant decreases in polyunsaturated linoleic acid (18:2n-6) (2.3% decrease) and linolenic acid (18:3n-3) (9.6% decrease) and a significant increase in monounsaturated fatty acids 17:1n-7 (30.3% increase) and 18:1n-7 (25% increase). The combined observations of decreased photosynthetic parameters and low nutrient availability in glyphosate-treated plants may explain potential adverse effects of glyphosate in GR soybeans.
Journal of Agricultural and Food Chemistry, 2003
The estrogenic isoflavones of soybeans and their glycosides are products of the shikimate pathway, the target pathway of glyphosate. This study tested the hypothesis that nonphytotoxic levels of glyphosate and other herbicides known to affect phenolic compound biosynthesis might influence levels of these nutraceutical compounds in glyphosate-resistant soybeans. The effects of glyphosate and other herbicides were determined on estrogenic isoflavones and shikimate in glyphosate-resistant soybeans from identical experiments conducted on different cultivars in Mississippi and Missouri. Four commonly used herbicide treatments were compared to a hand-weeded control. The herbicide treatments were (1) glyphosate at 1260 g/ha at 3 weeks after planting (WAP), followed by glyphosate at 840 g/ha at 6 WAP; (2) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied preemergence (PRE), followed by glyphosate at 1260 g/ha at 6 WAP; (3) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by glyphosate at 1260 g/ha at full bloom; and (4) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by acifluorfen at 280 g/ha plus bentazon at 560 g/ha plus clethodim at 140 g/ha at 6 WAP. Soybeans were harvested at maturity, and seeds were analyzed for daidzein, daidzin, genistein, genistin, glycitin, glycitein, shikimate, glyphosate, and the glyphosate degradation product, aminomethylphosphonic acid (AMPA). There were no remarkable effects of any treatment on the contents of any of the biosynthetic compounds in soybean seed from either test site, indicating that early and later season applications of glyphosate have no effects on phytoestrogen levels in glyphosate-resistant soybeans. Glyphosate and AMPA residues were higher in seeds from treatment 3 than from the other two treatments in which glyphosate was used earlier.