Halosulfuron (35 g a.i. ha −1 ) applied preemergence (PRE), early-postemergence (EPOST), and late-postemergence (LPOST) does not adequately control volunteer adzuki bean in white bean, but halosulfuron applied EPOST and LPOST has the potential to be used for control of volunteer soybean in white bean.
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, there was no adverse effect on velvetleaf, pigweed, common ragweed, common lambsquarters and green foxtail control, density and dry weight when one of the insecticides or fungicides evaluated was tankmixed with glyphosate. Based on these results, glyphosate tankmixed with cyhalothrin-lambda, dimethoate, imidacloprid/deltamethrin, spirotetramat, pyraclostrobin, azoxystrobin, propiconazole, azoxystrobin/propiconazole, tebuconazole or trifloxystrobin/propiconazole causes minimal crop injury and has no adverse effect on weed control in glyphosate-resistant soybean under Ontario environmental conditions.
Abstract Control of fall‐seeded annual ryegrass ( Lolium multiflorum Lam) cover crops with spring‐applied herbicides prior to seeding corn ( Zea mays L.) has been variable. Improved herbicide options are needed in order to increase the consistency of annual ryegrass termination prior to seeding corn. Four field experiments were conducted over a 2‐yr period (2018, 2019) in Ontario, Canada, to evaluate the control of fall‐seeded annual ryegrass cover crops with various corn herbicides, applied prior to seeding corn in the spring. Based on visual estimates, glyphosate alone controlled annual ryegrass 80% at 6 weeks after application (WAA). Acetolactate synthase (ALS) inhibitor herbicides, foramsulfuron, nicosulfuron, rimsulfuron, and nicosulfuron/rimsulfuron controlled annual ryegrass 82, 71, 88, and 88%, respectively, at 6 WAA. The tankmix of glyphosate with foramsulfuron, nicosulfuron, rimsulfuron, or nicosulfuron/rimsulfuron controlled annual ryegrass 94–98% at 6 WAA. Glyphosate reduced annual ryegrass density 73%; in contrast, foramsulfuron, nicosulfuron, rimsulfuron, and nicosulfuron/rimsulfuron did not reduce annual ryegrass density compared to the weedy control. The tankmix of glyphosate plus an ALS inhibitor herbicide reduced annual ryegrass density 88−94%. Reduced annual ryegrass interference with glyphosate applied alone resulted in an increase in corn yield of 86% compared to the control. Reduced annual ryegrass interference with foramsulfuron, nicosulfuron, rimsulfuron, and nicosulfuron/rimsulfuron applied alone resulted in an increase in corn yield 61, 61, 93, and 91%, and 98, 105, 95, and 98% when co‐applied with glyphosate, respectively. The tankmix of glyphosate with an ALS inhibitor herbicide resulted in excellent (>90%) annual ryegrass control and increased corn yield.
Abstract Six field experiments were established in southwestern Ontario in 2021 and 2022 to evaluate whether the addition of a grass herbicide (acetochlor, dimethenamid-p, flufenacet, pendimethalin, pyroxasulfone, or S -metolachlor) to tolpyralate + atrazine improves late-season weed control in corn. Tolpyralate + atrazine caused 12% and 5% corn injury at 1 and 4 wk after herbicide application (WAA); corn injury was not increased with the addition of a grass herbicide. Weed interference reduced corn yield 60%. The addition of a grass herbicide to tolpyralate + atrazine did not enhance velvetleaf control. The addition of acetochlor or dimethenamid-p to tolpyralate + atrazine enhanced pigweed species control 4% 4 WAA; the addition of other grass herbicides tested did not increase pigweed species control. The addition of acetochlor enhanced common ragweed control 5% at 4 WAA, and the addition of acetochlor or dimethenamid-p enhanced common ragweed control 8% at 8 WAA; the addition of other grass herbicides did not improve common ragweed control. The addition of acetochlor to tolpyralate + atrazine enhanced common lambsquarters control up to 4%; there was no enhancement in common lambsquarters control with the addition of the other grass herbicides. Tolpyralate + atrazine controlled barnyardgrass 90% and 78% at 4 and 8 WAA, respectively; the addition of a grass herbicide enhanced barnyardgrass control 9% to 10% and 21% at 4 and 8 WAA, respectively. Tolpyralate + atrazine controlled green or giant foxtail 80% and 69% at 4 and 8 WAA, respectively; the addition of a grass herbicide enhanced foxtail species control 15% to 19% and 24% to 29% at 4 and 8 WAA, respectively. This research shows that adding a grass herbicide to tolpyralate + atrazine mixture can improve weed control efficacy, especially increased annual grass control in corn production.
Thirteen herbicide tankmixes were evaluated during 2013–2015 for control of glyphosate-resistant (GR) Canada fleabane in soybean. Glyphosate + saflufenacil + s-metolachlor/metribuzin, glyphosate + amitrole, and glyphosate + metribuzin were the most efficacious, controlling 86%–92% of GR Canada fleabane, reducing density by 98%–99% and aboveground biomass by 96%–97%.
Abstract During 2016 and 2017, four field experiments were conducted at Huron Research Station near Exeter, ON, to evaluate the sensitivity of dry bean grown under a strip-tillage cropping system, to potential herbicides for the control of glyphosate-resistant (GR) horseweed. At 8 wk after emergence (WAE), saflufenacil, metribuzin, saflufenacil+metribuzin, 2,4-D ester, flumetsulam, cloransulam-methyl, and chlorimuron-ethyl caused 13% to 32%, 8% to 52%, 32% to 53%, 5% to 7%, 13% to 21%, 16% to 29%, and 23% to 43% visible injury in dry beans, respectively. Saflufenacil decreased aboveground biomass 65% in kidney bean and 80% in white bean. Metribuzin decreased biomass 82% in kidney bean and 50% in white bean. Saflufenacil+metribuzin decreased biomass 88% in kidney bean, 68% in small red bean, and 80% in white bean. Chlorimuron-ethyl decreased biomass 40% in white bean. There was no decrease in dry bean biomass with the other herbicides evaluated. Metribuzin and saflufenacil+metribuzin reduced kidney bean seed yield 72% and 76%, respectively. Saflufenacil+metribuzin, flumetsulam, cloransulam-methyl, and chlorimuron-ethyl reduced small red bean seed yield 39%, 27%, 30%, and 54%, respectively. Saflufenacil, metribuzin, saflufenacil+metribuzin, flumetsulam, cloransulam-methyl, and chlorimuron-ethyl reduced seed yield of white bean 52%, 32%, 62%, 33%, 42%, and 62%, respectively. There was no decrease in dry bean yield with the other herbicides evaluated. Among herbicides evaluated, 2,4-D ester caused the least crop injury with no effect in dry bean seed yield.
Weed interference from glyphosate/glufosinate-resistant (GGR) volunteer corn can reduce soybean yield and quality. The recent release of glyphosate/glufosinate/2,4-D choline (GG2)-resistant soybean will allow for expanded POST herbicide mixture options for broad-spectrum weed control. Herbicide antagonism between ACCase-inhibiting graminicides and synthetic auxin herbicides has been confirmed for various grass weed species, including volunteer corn. Field experiments (total of 4) were carried out in 2021 and 2022 in southwestern Ontario to assess volunteer corn control with combinations of glufosinate, 2,4-D choline, or dicamba plus clethodim or quizalofop-p-ethyl applied POST to GG2-resistant soybean. Quizalofop-p-ethyl and quizalofop-p-ethyl + glufosinate controlled GGR volunteer corn 95 and 98%, respectively, 6 weeks after application (WAA); adding 2,4-D choline or dicamba to quizalofop-p-ethyl reduced control to ≤ 15%. Clethodim controlled GGR volunteer corn 81%, and the addition of glufosinate increased control to 97%; the co-application of 2,4-D choline or dicamba with clethodim reduced GGR volunteer corn control to 58 and 45%, respectively at 6 WAA. ACCase-inhibiting herbicides co-applied with glufosinate resulted in a synergistic improvement in GGR volunteer corn control while co-applications with synthetic auxin herbicides resulted in an antagonistic decrease in GGR volunteer corn control. Greater antagonism occurred when the synthetic auxin herbicides were co-applied with quizalofop-p-ethyl than clethodim. All mixtures of quizalofop-p-ethyl or clethodim with 2,4-D or dicamba resulted in unacceptable control of GGR volunteer corn.
Three field experiments were completed over a three-year period (2019 to 2021) in Ontario, Canada to develop weed management programs in azuki bean with herbicides (pendimethalin, S-metolachlor, halosulfuron, and imazethapyr) applied alone and in combination, and metribuzin, applied preemergence (PRE). At 2 and 4 weeks after emergence (WAE), there was ≤ 8% azuki bean injury from the herbicide treatments evaluated, with the exception of the treatments that included S-metolachlor which caused up to 19% azuki bean injury. Pendimethalin (1080 g ai ha-1) and S-metolachlor (1600 g ai ha-1) controlled green foxtail 83-94% but provided poor control of common lambsquarters, wild mustard, redroot pigweed, common ragweed, and flower-of-an-hour. Imazethapyr (75 g ai ha-1) controlled common lambsquarters, wild mustard, redroot pigweed, and flower-of-an-hour 90-100% but provided 76-82% control of common ragweed and green foxtail. Halosulfuron (35 g ai ha-1) controlled wild mustard 100%, common ragweed 81-84%, common lambsquarters 77-83%, flower-of-an-hour 72-75%, redroot pigweed 59-72%, and green foxtail 19-23%. The tankmix of pendimethalin + S-metolachlor controlled green foxtail and common lambsquarters 87-97% but the control was only 23- 83% on wild mustard, redroot pigweed, common ragweed, and flower-of-an-hour. The tankmixes of pendimethalin + imazethapyr and pendimethalin + S-metolachlor + imazethapyr provided 90-100% control of common lambsquarters, wild mustard, redroot pigweed, flower-of-an-hour, and green foxtail, and 78-87% control of common ragweed. The tankmixes of pendimethalin + halosulfuron and pendimethalin + S-metolachlor + halosulfuron controlled common lambsquarters and wild mustard 91-100%, green foxtail 76-95%, flower-of-an-hour 70-94%, redroot pigweed 68-91%, and common ragweed 78-79%. Metribuzin (280 g ai ha-1) controlled common lambsquarters, wild mustard, redroot pigweed, common ragweed, flower-of-an-hour, and green foxtail up to 94, 98, 81, 58, 98, and 61% respectively; control improved to 99, 100, 97, 84, 99, and 83%, respectively when the rate was increased to 560 g ai ha-1. Generally, weed density and dry biomass reflected the level of weed control. Weed interference reduced azuki bean yield by 91% in this study. Generally, azuki bean yield reflected the level of weed control.
Research was conducted in 2017 and 2018 to determine the relative efficacy of five HPPD-inhibitors, tank-mixed with atrazine, for the control of multiple herbicide resistant waterhemp. At 12 wk after application (WAA), isoxaflutole + atrazine, mesotrione + atrazine, and tembotrione + atrazine, applied preemergence (PRE), controlled waterhemp 90%, 87%, and 81%, respectively. None of the HPPD-inhibiting herbicides applied PRE controlled waterhemp similar to the weed-free control 12 WAA. Applied postemergence, topramezone + atrazine, mesotrione + atrazine, tolpyralate + atrazine, and tembotrione + atrazine controlled waterhemp 87%, 94%, 97%, and 98% 12 WAA, respectively, and were all similar to the weed-free control.
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