Biologically effective rate of metribuzin for glyphosate-resistant Canada fleabane control in soybean (original) (raw)
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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...