scholarly journals Control of Glyphosate-Resistant Common Waterhemp (Amaranthus rudis) in Glufosinate-Resistant Soybean

2017 ◽  
Vol 31 (1) ◽  
pp. 32-45 ◽  
Author(s):  
Amit J. Jhala ◽  
Lowell D. Sandell ◽  
Debalin Sarangi ◽  
Greg R. Kruger ◽  
Steven Z. Knezevic

Glyphosate-resistant (GR) common waterhemp has become a significant problem weed in Nebraska and several Midwestern states. Several populations of GR common waterhemp are also resistant to acetolactate synthase (ALS)-inhibiting herbicides, making them difficult to control with POST herbicides in GR soybean. Glufosinate-resistant (GFR) soybean is an alternate system for controlling GR common waterhemp, justifying the need for evaluating glufosinate-based herbicide programs. The objectives of this study were to compare POST-only herbicide programs (including one-pass and two-pass POST programs) with PRE followed by (fb) POST herbicide programs for control of GR common waterhemp in GFR soybean and their effect on common waterhemp density, biomass, and soybean yield. Field experiments were conducted in 2013 and 2014 near Fremont, NE in a grower’s field infested with GR common waterhemp. Glufosinate applied early- and late-POST provided 76% control of GR common waterhemp at 14 d after late-POST (DALPOST) compared with 93% control with a PRE fb POST program when averaged across treatments. The PRE application of chlorimuron plus thifensulfuron plus flumioxazin,S-metolachlor plus fomesafen or metribuzin, saflufenacil plus dimethenamid-P fb glufosinate provided ≥95% control of common waterhemp throughout the growing season, reduced common waterhemp density to ≤2.0 plants m─2, caused ≥94% biomass reduction, and led to 1,984 to 2,210 kg ha─1soybean yield. Averaged across treatments, the PRE fb POST program provided 82% common waterhemp control at soybean harvest, reduced density to 23 plants m─2at 14 DALPOST, and caused 86% biomass reduction and 1,803 kg ha─1soybean yield compared with 77% control, 99 plants m─2, 53% biomass reduction, and 1,190 kg ha─1yield with POST-only program. It is concluded that PRE fb POST programs with multiple effective modes of action are available for control of GR common waterhemp in GFR soybean.

2017 ◽  
Vol 31 (1) ◽  
pp. 53-66 ◽  
Author(s):  
Debalin Sarangi ◽  
Lowell D. Sandell ◽  
Greg R. Kruger ◽  
Stevan Z. Knezevic ◽  
Suat Irmak ◽  
...  

The evolution of glyphosate and acetolactate synthase (ALS) inhibitor-resistant common waterhemp in the Midwestern United States has reduced the number of effective POST herbicide options for management of this problem weed in glyphosate-resistant soybean. Moreover, common waterhemp emerges throughout the crop growing season, justifying the need to evaluate herbicide programs that provide season-long control. The objectives of this study were to compare POST-only and PRE followed by (fb) POST herbicide programs for control of glyphosate-resistant common waterhemp in glyphosate-resistant soybean. Field experiments were conducted in 2013 and 2014 in Dodge County, NE, in a field infested with glyphosate-resistant common waterhemp. Programs containing PRE herbicides resulted in ≥83% control of common waterhemp and densities of ≤35 plantsm–2at 21 d after PRE (DAPRE). Post-only herbicide programs resulted in <70% control and densities of 107 to 215 plants m–2at 14 d after early-POST (DAEPOST) treatment. PRE fb POST herbicide programs, including saflufenacil plus imazethapyr plus dimethenamid-P, sulfentrazone plus cloransulam, orS-metolachlor plus metribuzin, fb fomesafen plus glyphosate;S-metolachlor plus fomesafen fb acifluorfen plus glyphosate resulted in >90% control of glyphosate-resistant common waterhemp throughout the growing season, reduced density to ≤7plantsm–2, ≥92% biomass reduction, and soybean yield >2,200kg ha–1. Averaged across herbicide programs, common waterhemp control was 84%, and density was 15 plants m–2with PRE fb POST herbicide programs compared with 42% control, and density of 101 plants m–2with POST-only herbicide programs at harvest. Results of this study indicated that PRE fb POST herbicide programs with effective modes of action exist for season-long control of glyphosate-resistant common waterhemp in glyphosate-resistant soybean.


2020 ◽  
pp. 1-8
Author(s):  
Chandrima Shyam ◽  
Parminder S. Chahal ◽  
Amit J. Jhala ◽  
Mithila Jugulam

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.


2015 ◽  
Vol 29 (3) ◽  
pp. 419-430 ◽  
Author(s):  
Jatinder S. Aulakh ◽  
Amit J. Jhala

Because of the increasing number of glyphosate-resistant weeds, alternate herbicide-resistant crops and herbicides with different modes of action are required to protect crop yield. Glufosinate is a broad-spectrum POST herbicide for weed control in glufosinate-resistant crops, including soybean. The objective of this study was to compare herbicide programs with glufosinate applied singly at late-POST (LPOST) or sequentially at early POST (EPOST) followed by (fb) LPOST applications and PRE herbicides fb EPOST/LPOST glufosinate alone or tank-mixed with acetochlor, pyroxasulfone, orS-metolachlor in glufosinate-resistant soybean. A field experiment was conducted at the South Central Agriculture Laboratory in Clay Center, NE, in 2012 and 2013. Glufosinate applied in a single LPOST or sequential EPOST fb LPOST application controlled common lambsquarters, common waterhemp, eastern black nightshade, green foxtail, large crabgrass, and velvetleaf ≤ 82% and resulted in a weed density of 6 to 10 plants m−2by the end of the season. Flumioxazin-, saflufenacil-, or sulfentrazone-based premixes provided 84 to 99% control of broadleaf and grass weeds tested in this study at 15 d after PRE application and a subsequent LPOST application of glufosinate alone controlled broadleaf and grass weeds 69 to 93% at harvest, depending on the herbicide program and weed species being investigated. The PRE application of sulfentrazone plus metribuzin fb EPOST glufosinate tank-mixed with acetochlor, pyroxasulfone, orS-metolachlor controlled the tested broadleaf and grass weeds ≥ 90%, reduced density to ≤ 2 plants m−2, and reduced weed biomass to ≤ 10 g m−2and produced soybean yields of ≥ 4,450 and 3,040 kg ha−1in 2012 and 2013, respectively. Soybean injury was 0 to 20% from PRE or POST herbicides, or both and was inconsistent, but transient, during the 2-yr study, and it did not affect soybean yield. Sulfentrazone plus metribuzin applied PRE fb glufosinate EPOST tank-mixed with acetochlor, pyroxasulfone, orS-metolachlor provided the highest level of weed control throughout the growing season and increased soybean yield compared with a single LPOST or a sequential EPOST fb LPOST glufosinate application. Additionally, these herbicide programs provide four distinct mechanisms of action that constitute an effective weed-resistance management strategy in glufosinate-resistant soybean.


Weed Science ◽  
2008 ◽  
Vol 56 (4) ◽  
pp. 582-587 ◽  
Author(s):  
Travis R. Legleiter ◽  
Kevin W. Bradley

Field and greenhouse experiments were conducted to determine the level of glyphosate resistance in common waterhemp populations from Platte County (MO1) and Holt County, Missouri (MO2), and to determine the level and distribution of resistance to glyphosate, acetolactate synthase (ALS)–inhibiting herbicides, and protoporophyrinogen oxidase (PPO)–inhibiting herbicides across the MO1 site. Results from greenhouse experiments revealed that the MO1 and MO2 waterhemp populations were 19 and 9 times more resistant to glyphosate, respectively, than a susceptible waterhemp population. In field experiments, greater than 54% of waterhemp at the MO1 site survived 1.7 kg glyphosate ae ha−1(twice the labeled rate) 6 wk after treatment. Tank-mix combinations of ALS- and PPO-inhibiting herbicides with glyphosate also failed to provide complete control of the waterhemp population at the MO1 site. Collection and screening of seed from individual female waterhemp accessions revealed multiple resistance to glyphosate, ALS-, and PPO-inhibiting herbicides across the MO1 site. All 14 waterhemp accessions collected across the MO1 site exhibited greater than 65% survival to 2× rates of glyphosate and thifensulfuron, and these accessions were spread across a 5-km2(503-ha) area. Four waterhemp accessions collected across a 0.9-km2(87-ha) area also exhibited 26 to 38% survival to 2× rates of lactofen. The results from these experiments provide evidence and confirmation of the first glyphosate-resistant waterhemp population in the United States and reveal that multiple resistance to glyphosate, ALS-, and PPO-inhibiting herbicides can occur in waterhemp.


2020 ◽  
Vol 100 (6) ◽  
pp. 629-641
Author(s):  
Zahoor A. Ganie ◽  
Amit J. Jhala

A soybean trait resistant to sulfonylurea herbicides along with glyphosate (Bolt™ soybean) has been developed. Information is needed to determine herbicide programs for weed control and crop safety in this new multiple herbicide–resistant soybean trait. The objectives of this study were to evaluate weed control and crop safety in sulfonylurea/glyphosate-resistant soybean with herbicide programs, including but not limited to acetolactate synthase (ALS) inhibitors. Field experiments were conducted near Clay Center, NE, USA, in 2016 and 2017. Herbicide programs with multiple sites-of-action including rimsulfuron/thifensulfuron in mixture with flumioxazin, flumioxazin/chlorimuron, pyroxasulfone, chlorimuron/metribuzin, or saflufenacil/imazethapyr plus dimethenamid-P provided 91%–97% control of common waterhemp, velvetleaf, and common lambsquarters. Rimsulfuron and (or) thifensulfuron resulted in 92%–97% control of velvetleaf and common lambsquarters and 81%–87% common waterhemp control at 21 d after pre-emergence (PRE) (DAPRE) herbicide application. Soybean injury was transient and varied from 3% to 11% at 21 DAPRE and 14 d after post-emergence (POST) (DAPOST) herbicide application without causing yield loss. At 30 and 60 DAPOST, 87%–97% velvetleaf control and 92%–98% common lambsquarters control was achieved with herbicide programs tested (PRE, POST, or PRE followed by POST). Common waterhemp control at 30 and 60 DAPOST was not consistent between years. Weed density and biomass reduction were mostly similar to weed control achieved. Untreated control resulted in the lowest soybean yield (1811 kg ha−1) in 2016 compared with 3406–4611 kg ha−1 in herbicide programs.


2019 ◽  
Vol 33 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Marshall M. Hay ◽  
Douglas E. Shoup ◽  
Dallas E. Peterson

AbstractDouble-crop soybean after winter wheat is a component of many cropping systems across eastern and central Kansas. Until recently, control of Palmer amaranth and common waterhemp has been both easy and economical with the use of sequential applications of glyphosate in glyphosate-resistant soybean. Many populations of Palmer amaranth and common waterhemp have become resistant to glyphosate. During 2015 and 2016, a total of five field experiments were conducted near Manhattan, Hutchinson, and Ottawa, KS, to assess various non-glyphosate herbicide programs at three different application timings for the control of Palmer amaranth and waterhemp in double-crop soybean after winter wheat. Spring-POST treatments of pyroxasulfone (119 g ai ha–1) and pendimethalin (1065 g ai ha–1) were applied to winter wheat to evaluate residual control of Palmer amaranth and waterhemp. Less than 40% control of Palmer amaranth and waterhemp was observed in both treatments 2 wk after planting (WAP) double-crop soybean. Preharvest treatments of 2,4-D (561 g ae ha–1) and flumioxazin (107 g ai ha–1) were also applied to the winter wheat to assess control of emerged Palmer amaranth and waterhemp. 2,4-D resulted in highly variable Palmer amaranth and waterhemp control, whereas flumioxazin resulted in control similar to PRE treatments that contained paraquat (841 g ai ha–1) plus residual herbicide(s). Excellent control of both species was observed 2 WAP with a PRE paraquat application; however, reduced control of Palmer amaranth and waterhemp was noted 8 WAP due to subsequent emergence. Results indicate that Palmer amaranth and waterhemp control was 85% or greater 8 WAP for PRE treatments that included a combination of paraquat plus residual herbicide(s). PRE treatments that did not include both paraquat and residual herbicide(s) did not provide acceptable control.


2009 ◽  
Vol 89 (1) ◽  
pp. 127-132 ◽  
Author(s):  
Nader Soltani ◽  
Joshua D Vyn ◽  
Peter H Sikkema

Common waterhemp (Amaranthus tuberculatus) is an aggressive annual broadleaf whose distribution is expected to increase rapidly in agricultural land in eastern Canada. Eight field experiments (four in corn and four in soybean) over a 2-yr period (2005 and 2006) were established on two Ontario farms (near Comber and Petrolia, Ontario) with waterhemp infestations to evaluate the efficacy of various PRE- and POST-emergence herbicides applied alone or in sequence for the control of waterhemp in corn and soybean. There was minimal injury (up to 3.8%) to corn and soybean from the herbicide treatments evaluated. In corn, sequential herbicide programs of isoxaflutole + atrazine PRE fb either dicamba POST, dicamba/diflufenzopyr POST, dicamba/atrazine POST or mesotrione + atrazine POST provided consistent full-season control of waterhemp. Corn yield was reduced 48% when waterhemp was not controlled. Corn yield was equivalent to the weed-free check with the herbicide treatments evaluated. In soybean, PRE or POST herbicides alone provided 41 to 94% control of waterhemp, however, waterhemp control was increased to 90 to 99% with the sequential herbicide programs. Dimethenamid (PRE; 1250 g ha-1) followed by glyphosate (POST1; 900 g ha-1) followed by glyphosate (POST2; 900 g ha-1) controlled waterhemp 99%. Results with waterhemp density and biomass were similar to visible control. Soybean yield was reduced 41% when waterhemp was not controlled. Soybean yield was equivalent to the weed-free check with all the herbicide treatment except dimethenamid PRE, acifluorfen POST1 and fomesafen POST1 where the yield was 30, 19, and 19% lower, respectively. Key words: Waterhemp, weed control, glyphosate, corn, soybean, pre-emergence herbicide, post-emergence herbicide


2021 ◽  
pp. 1-21
Author(s):  
Jose H. S. de Sanctis ◽  
Amit J. Jhala

Abstract Velvetleaf is an economically important weed in agronomic crops in Nebraska and the United States. Dicamba applied alone usually does not provide complete velvetleaf control, particularly when velvetleaf is greater than 15 cm tall. The objectives of this experiment were to evaluate the interaction of dicamba, fluthiacet-methyl, and glyphosate applied alone or in a mixture in two- or three-way combinations for velvetleaf control in dicamba/glyphosate-resistant (DGR) soybean and to evaluate whether velvetleaf height (≤ 12 cm or ≤ 20 cm) at the time of herbicide application influences herbicide efficacy, velvetleaf density, biomass, and soybean yield. Field experiments were conducted near Clay Center, Nebraska in 2019 and 2020. The experiment was arranged in a split-plot with velvetleaf height (≤ 12 cm or ≤ 20 cm) as the main plot treatment and herbicides as sub-plot treatment. Fluthiacet provided ≥ 94% velvetleaf control 28 d after treatment (DAT) and ≥ 96% biomass reduction regardless of application rate or velvetleaf height. Velvetleaf control was 31% to 74% at 28 DAT when dicamba or glyphosate was applied alone to velvetleaf ≤ 20 cm tall compared with 47% to 100% control applied to ≤ 12 cm tall plants. Dicamba applied alone to ≤ 20 cm tall velvetleaf provided < 75% control and < 87% biomass reduction 28 DAT compared with ≥ 90% control with dicamba at 560 g ae ha−1 + fluthiacet at 7.2 g ai ha−1 or glyphosate at 1,260 g ae ha−1. Dicmaba at 280 g ae ha−1 + glyphosate at 630 g ae ha−1 applied to ≤ 20 cm tall velvetleaf resulted in 86% control 28 DAT compared with the expected 99% control. The interaction of dicamba + fluthiacet + glyphosate was additive for velvetleaf control and biomass reduction regardless of application rate and velvetleaf height.


Weed Science ◽  
1996 ◽  
Vol 44 (4) ◽  
pp. 789-794 ◽  
Author(s):  
Sarah Taylor Lovell ◽  
Loyd M. Wax ◽  
Michael J. Horak ◽  
Dallas E. Peterson

The incidence of weed resistance to acetolactate synthase (ALS) inhibiting herbicides has increased in the United States. In 1993, a population of ALS-resistant common waterhemp was discovered after two confirmed applications of an imidazolinone herbicide. Following another imazethapyr application in the glasshouse, the resistant biotype demonstrated 130-fold resistance to imazethapyr at the whole plant level. The concentration of imazethapyr required to inhibit the ALS activity by 50% was 520 times greater for the resistant biotype than the susceptible. Plants also demonstrated cross-resistance to the sulfonylureas, chlorimuron and thifensulfuron, at the whole plant and enzyme levels. This particular discovery is of concern due to the low number of applications of the selection agent (imazaquin 1989, imazethapyr 1992, and imazethapyr in the greenhouse) and the high degree of cross-resistance eliminating several options for weed control.


1997 ◽  
Vol 11 (1) ◽  
pp. 13-18 ◽  
Author(s):  
John R. R. Hinz ◽  
Micheal D. K. Owen

Research was initiated to determine (a) whether a common waterhemp population was resistant to acetolactate synthase (ALS) inhibiting herbicides, (b) the percentage of the population that was ALS-inhibitor resistant, (c) the resistance mechanism, and (d) the effectiveness of a whole plant assay to detect ALS-inhibitor resistance. ALS-inhibitor resistance was confirmed in a common waterhemp population near Davis City, IA. The Davis City common waterhemp population was cross resistant to both imidazolinone and sulfonylurea herbicides, but not to lactofen. Approximately 10% of the Davis City common waterhemp population was sensitive to a rate of imazaquin 4 times the normal field rate. Davis City common waterhemp isolated ALS was much less sensitive to imazaquin and primisulfuron inhibition than was grain amaranth or an ALS-sensitive common waterhemp isolated ALS. Imazaquin I50values were 366.4 and 3.4 μM for ALS isolated from Davis City common waterhemp and grain amaranth, respectively. Primisulfuron I50values were 3.6 and 0.007 μM for ALS isolated from Davis City common waterhemp and grain amaranth, respectively. A whole plant ALS assay was developed that allowed for much more rapid detection of an ALS-resistant species and used less plant material than a conventional ALS assay.


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