Effective two-pass herbicide programs to control glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in glyphosate/dicamba-resistant soybean

2020 ◽  
pp. 1-8
Author(s):  
Vipan Kumar ◽  
Rui Liu ◽  
Dallas E. Peterson ◽  
Phillip W. Stahlman
Keyword(s):  
Grain Yield ◽  
Selection Pressure ◽  
Field Experiments ◽  
Agricultural Research ◽  
Palmer Amaranth ◽  
Shoot Biomass ◽  
Amaranthus Palmeri ◽  
State University ◽  
Kansas State University ◽  
Herbicide Programs

Abstract Field experiments were conducted in 2018 and 2019 at Kansas State University Ashland Bottoms (KSU-AB) research farm near Manhattan, KS, and Kansas State University Agricultural Research Center (KSU-ARC) near Hays, KS, to determine the effectiveness of various PRE-applied herbicide premixes and tank mixtures alone or followed by (fb) an early POST (EPOST) treatment of glyphosate + dicamba for controlling glyphosate-resistant (GR) Palmer amaranth in glyphosate/dicamba-resistant (GDR) soybean. In experiment 1, PRE-applied sulfentrazone + S-metolachlor, saflufenacil + imazethapyr + pyroxasulfone, chlorimuron + flumioxazin + pyroxasulfone, and metribuzin + flumioxazin + imazethapyr provided 85% to 94% end-of-season control of GR Palmer amaranth across both sites. In comparison, Palmer amaranth control ranged from 63% to 87% at final evaluation with PRE-applied pyroxasulfone + sulfentrazone, pyroxasulfone + sulfentrazone plus metribuzin, pyroxasulfone + sulfentrazone plus carfentrazone + sulfentrazone, and sulfentrazone + metribuzin at the KSU-ARC site in experiment 2. All PRE fb EPOST (i.e., two-pass) programs provided near-complete (98% to 100%) control of GR Palmer amaranth at both sites. PRE-alone programs reduced Palmer amaranth shoot biomass by 35% to 76% in experiment 1 at both sites, whereas all two-pass programs prevented Palmer amaranth biomass production. No differences in soybean yields were observed among tested programs in experiment 1 at KSU-ARC site; however, PRE-alone sulfentrazone + S-metolachlor, saflufenacil + imazethapyr + pyroxasulfone, and chlorimuron + flumioxazin + pyroxasulfone had lower grain yield (average, 4,342 kg ha−1) compared with the top yielding (4,832 kg ha−1) treatment at the KSU-AB site. PRE-applied sulfentrazone + metribuzin had a lower soybean yield (1,776 kg ha−1) compared with all other programs in experiment 2 at the KSU-ARC site. These results suggest growers should proactively adopt effective PRE-applied premixes fb EPOST programs evaluated in this study to reduce selection pressure from multiple POST dicamba applications for GR Palmer amaranth control in GDR soybean.

Palmer Amaranth (Amaranthus palmeri) Control in Postharvest Wheat Stubble in the Central Great Plains

2021 ◽  
pp. 1-17
Author(s):  
Vipan Kumar ◽  
Rui Liu ◽  
Amit J. Jhala ◽  
Prashant Jha ◽  
Misha Manuchehri
Keyword(s):  
Seed Production ◽  
Great Plains ◽  
Field Experiments ◽  
Agricultural Research ◽  
Palmer Amaranth ◽  
Shoot Biomass ◽  
Late Season ◽  
Growing Seasons ◽  
Wheat Stubble ◽  
Kansas State University

Abstract Late-season control of Palmer amaranth in postharvest wheat stubble is important for reducing the seedbank. Our objectives were to evaluate the efficacy of late-season POST herbicides for Palmer amaranth control, shoot dry biomass and seed production in postharvest wheat stubble. Field experiments were conducted at Kansas State University Agricultural Research Center near Hays, KS during 2019 and 2020 growing seasons. The study site had a natural seedbank of Palmer amaranth. Herbicide treatments were applied 3 wk after wheat harvest when Palmer amaranth plants had reached inflorescence initiation stage. Palmer amaranth was controlled 96 to 98% 8 weeks after treatment and shoot biomass as well as seed production was prevented when paraquat was applied alone or when mixed with atrazine, metribuzin, flumioxazin, 2,4-D, sulfentrazone, pyroxasulfone + sulfentrazone, or flumioxazin + metribuzin, and with glyphosate + dicamba, glyphosate + 2,4-D, saflufenacil + 2,4-D, glufosinate + dicamba + glyphosate, and glufosinate + 2,4-D + glyphosate. Palmer amaranth was controlled 89 to 93% with application of glyphosate, glufosinate, dicamba + 2,4-D, saflufenacil + atrazine, and saflufenacil + metribuzin resulting in Palmer amaranth shoot biomass of 15 to 56 g m -2 and production of 1,080 to 7,040 seeds m−2. Palmer amaranth control was less than 86% with application of dicamba, 2,4-D, dicamba + atrazine, and saflufenacil resulting in Palmer amaranth shoot biomass of 38 to 47 g m−2 and production of 3,110 to 6,190 seeds m−2. Palmer amaranth was controlled 63 and 72%, shoot biomass was 178 and 161 g m−2 and seed production was 35,180 and 39,510 seeds m−2, respectively, with application of 2,4-D + bromoxynil + fluroxypyr, and bromoxynil + pyrasulfotole + atrazine. Growers should utilize these effective POST herbicide mixes for Palmer amaranth control to prevent seed prevention postharvest in wheat stubble.

Management of glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in 2,4-D–, glufosinate-, and glyphosate-resistant soybean

2020 ◽  
pp. 1-8
Author(s):  
Chandrima Shyam ◽  
Parminder S. Chahal ◽  
Amit J. Jhala ◽  
Mithila Jugulam
Keyword(s):  
United States ◽  
Field Experiments ◽  
The United States ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Soybean Yield ◽  
Chlorimuron Ethyl ◽  
Density And Biomass ◽  
Herbicide Programs ◽  
Biomass Reduction

Abstract Glyphosate-resistant (GR) Palmer amaranth is a problematic, annual broadleaf weed in soybean production fields in Nebraska and many other states in the United States. Soybean resistant to 2,4-D, glyphosate, and glufosinate (Enlist E3TM) has been developed and was first grown commercially in 2019. The objectives of this research were to evaluate the effect of herbicide programs applied PRE, PRE followed by (fb) late-POST (LPOST), and early-POST (EPOST) fb LPOST on GR Palmer amaranth control, density, and biomass reduction, soybean injury, and yield. Field experiments were conducted near Carleton, NE, in 2018, and 2019 in a grower’s field infested with GR Palmer amaranth in 2,4-D–, glyphosate-, and glufosinate-resistant soybean. Sulfentrazone + cloransulam-methyl, imazethapyr + saflufenacil + pyroxasulfone, and chlorimuron ethyl + flumioxazin + metribuzin applied PRE provided 84% to 97% control of GR Palmer amaranth compared with the nontreated control 14 d after PRE. Averaged across herbicide programs, PRE fb 2,4-D and/or glufosinate, and sequential application of 2,4-D or glufosinate applied EPOST fb LPOST resulted in 92% and 88% control of GR Palmer amaranth, respectively, compared with 62% control with PRE-only programs 14 d after LPOST. Reductions in Palmer amaranth biomass followed the same trend; however, Palmer amaranth density was reduced 98% in EPOST fb LPOST programs compared with 91% reduction in PRE fb LPOST and 76% reduction in PRE-only programs. PRE fb LPOST and EPOST fb LPOST programs resulted in an average soybean yield of 4,478 and 4,706 kg ha−1, respectively, compared with 3,043 kg ha−1 in PRE-only programs. Herbicide programs evaluated in this study resulted in no soybean injury. The results of this research illustrate that herbicide programs are available for the management of GR Palmer amaranth in 2,4-D–, glyphosate-, and glufosinate-resistant soybean.

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.

Management of Large, Glyphosate-Resistant Palmer Amaranth (Amaranthus palmeri) in Corn

2016 ◽  
Vol 30 (3) ◽  
pp. 611-616 ◽  
Author(s):  
Whitney D. Crow ◽  
Lawrence E. Steckel ◽  
Thomas C. Mueller ◽  
Robert M. Hayes
Keyword(s):  
Photosystem Ii ◽  
Grain Yield ◽  
Environmental Conditions ◽  
Palmer Amaranth ◽  
Growth Stages ◽  
Corn Yield ◽  
Amaranthus Palmeri ◽  
Or Management ◽  
Herbicide Programs

Palmer amaranth is a very problematic weed that has evolved resistance to several classes of herbicides, including 5-enolypyruvylshikimate-3-phosate synthase–inhibiting herbicides and photosystem II–inhibiting herbicides. In recent years, corn producers have had difficulty controlling large Palmer amaranth (> 20 cm) in corn > 30 cm whether it be due to environmental conditions or management failures. Palmer amaranth management in corn this tall is made even more challenging because atrazine is not labeled POST in corn > 30 cm tall. Therefore, a study was conducted in 2013 and 2014 in Jackson, TN, to evaluate herbicide programs in corn > 30 cm tall for the control of glyphosate-resistant Palmer amaranth > 20 cm tall. Treatments consisted of herbicides applied alone and in mixtures with dicamba plus diflufenzopyr. Herbicides were applied POST to corn between the V5 and V6 growth stages. Dicamba plus diflufenzopyr 28 d after application controlled Palmer amaranth > 87%. The herbicides alone or in combinations applied as tank mixtures did not improve control (< 76%) over dicamba plus diflufenzopyr alone. There were no grain-yield differences among treatments because of Palmer amaranth control. This was likely due to the Palmer amaranth competition having already affected corn yield by the V5 to V6 corn growth stages.

scholarly journals Soybean density and Palmer amaranth (Amaranthus palmeri) establishment time: effects on weed biology, crop yield, and economic returns

Weed Science ◽  
2020 ◽  
Vol 68 (5) ◽  
pp. 467-475
Author(s):  
Nicholas E. Korres ◽  
Jason K. Norsworthy ◽  
Andy Mauromoustakos ◽  
Martin M. Williams
Keyword(s):  
Grain Yield ◽  
Seed Production ◽  
Crop Yield ◽  
Field Experiments ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Net Income ◽  
Seeding Rate ◽  
Weed Biology ◽  
Budget Analysis

AbstractKnowledge of crop–weed interference effects on weed biology along with yield penalties can be used for the development of integrated weed management (IWM) tactics. Nevertheless, little is known about the beneficial effects of soybean [Glycine max (L.) Merr.] density, an important aspect of IWM, on late Palmer amaranth (Amaranthus palmeri S. Watson) establishment time. Two field experiments were conducted in 2014 and 2015 to investigate how various soybean densities and A. palmeri establishment timings in weeks after crop emergence (WAE) affect height, biomass, and seed production of the weed but also crop yield in drill-seeded soybean. Soybean density had a significant impact on dry weight and seed production of A. palmeri that established within the first 2 wk of crop emergence, but not for establishment timings of the weed 4 wk and later in relation to crop emergence. Differential performance of A. palmeri gender was observed, regarding greater biomass production of female than male plants under crop presence, and merits further investigation. Grain yield reductions were recorded at earlier A. palmeri establishment timings (i.e., 0 and 1 WAE) compared with 8 WAE establishment timing in 2014 and 2015. High soybean densities resulted in greater soybean yields compared with low soybean density, but no grain yield benefits were observed between medium and high soybean densities. Crop budget analysis revealed the benefits of moderate seeding rate (i.e., 250, 000 seeds ha−1) increases in comparison to lower (i.e., 125,000 seeds ha−1) or high (i.e., 400,000 seeds ha−1) on crop revenue, net income returns, and breakeven price. Earlier A. palmeri establishment timings (i.e., 0, 1, and 2 WAE) resulted in lower crop revenue and net income returns compared with later establishment timings of the weed.

scholarly journals Control of Volunteer Glyphosate-Resistant Canola in Glyphosate-Resistant Sugar Beet

2015 ◽  
Vol 29 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha
Keyword(s):  
Sugar Beet ◽  
Field Experiments ◽  
Agricultural Research ◽  
Effective Control ◽  
Additional Advantage ◽  
Leaf Stage ◽  
Beet Root ◽  
Control Volunteer ◽  
Sugar Beet Root ◽  
Herbicide Programs

Occurrence of glyphosate-resistant (GR) canola volunteers in GR sugar beet is a management concern for growers in the Northern Great Plains. Field experiments were conducted at the Southern Agricultural Research Center near Huntley, MT, in 2011 and 2012 to evaluate effective herbicide programs to control volunteer GR canola in GR sugar beet. Single POST application of triflusulfuron methyl alone at the two-leaf stage of sugar beet was more effective at 35 compared with 17.5 g ai ha−1. However, rate differences were not evident when triflusulfuron methyl was applied as a sequential POST (two-leaf followed by [fb] six-leaf stage of sugar beet) program (17.5 fb 17.5 or 35 fb 35 g ha−1). Volunteer GR canola plants in the sequential POST triflusulfuron methyl–containing treatments produced little biomass (11 to 15% of nontreated plots) but a significant amount of seeds (160 to 661 seeds m−2). Ethofumesate (4,200 g ai ha−1) PRE followed by sequential POST triflusulfuron methyl (17.5 or 35 g ha−1) provided effective control (94 to 98% at 30 d after treatment [DAT]), biomass reduction (97%), and seed prevention of volunteer GR canola. There was no additional advantage of adding either desmedipham + phenmedipham + ethofumesate premix (44.7 g ha−1) or ethofumesate (140 g ha−1) to the sequential POST triflusulfuron methyl–only treatments. The sequential POST ethofumesate-only (140 fb 140 g ha−1) treatment provided poor volunteer GR canola control at 30 DAT, and the noncontrolled plants produced 6,361 seeds m−2, which was comparable to the nontreated control (7,593 seeds m−2). Sequential POST triflusulfuron methyl–containing treatments reduced GR sugar beet root and sucrose yields to 18 and 20%, respectively. Consistent with GR canola control, sugar beet root and sucrose yields were highest (95 and 91% of hand-weeded plots, respectively) when the sequential POST triflusulfuron methyl–containing treatments were preceded by ethofumesate (4,200 g ha−1) PRE. Growers should utilize these effective herbicide programs to control volunteer GR canola in GR sugar beet. Because of high canola seed production potential, as evident from this research, control efforts should be aimed at preventing seed bank replenishment of the GR canola volunteers.

Herbicide Management Strategies in Field Corn for a Three-Way Herbicide-Resistant Palmer Amaranth (Amaranthus palmeri) Population

2017 ◽  
Vol 31 (3) ◽  
pp. 364-372 ◽  
Author(s):  
Jonathon R. Kohrt ◽  
Christy L. Sprague
Keyword(s):  
Field Experiments ◽  
Management Strategies ◽  
Palmer Amaranth ◽  
Late Season ◽  
Field Corn ◽  
Group 5 ◽  
Group 2 ◽  
Sites Of Action ◽  
Residual Herbicide ◽  
Herbicide Programs

Three field experiments were conducted from 2013 to 2015 in Barry County, MI to evaluate the effectiveness of PRE, POST, and one- (EPOS) and two-pass (PRE followed by POST) herbicide programs for management of multiple-resistant Palmer amaranth in field corn. The Palmer amaranth population at this location has demonstrated resistance to glyphosate (Group 9), ALS-inhibiting herbicides (Group 2), and atrazine (Group 5). In the PRE only experiment, the only herbicide treatments that consistently provided ~80% or greater control were pyroxasulfone and the combination of mesotrione +S-metolachlor. However, none of these treatments provided season-long Palmer amaranth control. Only topramezone provided >85% Palmer amaranth control 14 DAT, in the POST only experiment. Of the 19 herbicide programs studied all but three programs provided ≥88% Palmer amaranth control at corn harvest. Herbicide programs that did not control Palmer amaranth relied on only one effective herbicide site of action and in one case did not include a residual herbicide POST for late-season Palmer amaranth control. Some of the EPOS treatments were effective for season-long Palmer amaranth control; however, application timing and the inclusion of a residual herbicide component will be critical for controlling Palmer amaranth. The programs that consistently provided the highest levels of season-long Palmer amaranth control were PRE followed by POST herbicide programs that relied on a minimum of two effective herbicide sites of action and usually included a residual herbicide for late-season control.

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.

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