Glyphosate- and acetolactate synthase inhibitor-resistant kochia (Bassia scoparia) control in field pea

Kochia [Bassia scoparia (L.) A.J. Scott] is an invasive C4 tumbleweed in the Great Plains of North America, where it impedes crop harvest and causes significant crop yield losses. Rapid evolution and spread of glyphosate- and acetolactate synthase (ALS) inhibitor-resistant kochia in western Canada limit the herbicide options available for control of these biotypes in field pea (Pisum sativum L.); one of the predominant pulse crops grown in this region. Field experiments were conducted near Lethbridge, Alberta in 2013-2015 and Coalhurst, Alberta in 2013-2014 to determine which herbicide options effectively control glyphosate- and ALS inhibitor-resistant kochia in field pea. Visible injury of field pea was minor (0-4%) in all environments except for Lethbridge 2013, where pre-plant (PP) flumioxazin and all treatments containing post-emergence (POST) imazamox/bentazon resulted in unacceptable (14-23%) pea visible injury. Herbicide impacts on pea yield were minor overall. Carfentrazone + sulfentrazone PP and saflufenacil PP followed by imazamox/bentazon POST resulted in ≥80% visible control of kochia in all environments, while POST imazamox/bentazon alone resulted in ≥80% reduction in kochia biomass in all environments compared with the untreated control (albeit absent of statistical difference in Coalhurst 2014). These results suggest that layering the protoporhyrinogen oxidase-inhibiting herbicides saflufenacil or carfentrazone + sulfentrazone PP with the ALS- and photosystem II-inhibiting herbicide combination imazamox/bentazon POST can effectively control glyphosate- and ALS inhibitor-resistant kochia in field pea while also mitigating further selection for herbicide resistance through the use of multiple effective herbicide modes-of-action.

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Control of acetolactate synthase inhibitor/glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in isoxaflutole/glufosinate/glyphosate-resistant soybean

Weed Technology ◽

10.1017/wet.2021.49 ◽

2021 ◽

pp. 1-23

Author(s):

Jasmine Mausbach ◽

Suat Irmak ◽

Debalin Sarangi ◽

John Lindquist ◽

Amit J. Jhala

Keyword(s):

Field Experiments ◽

Cropping Systems ◽

Acetolactate Synthase ◽

The United States ◽

Palmer Amaranth ◽

Effective Control ◽

Synthase Inhibitor ◽

Density And Biomass ◽

Als Inhibitor ◽

Herbicide Programs

Abstract Palmer amaranth is the most problematic and troublesome weed in agronomic cropping systems in the United States. Acetolactate synthase (ALS) inhibitor- and glyphosate-resistant (GR) Palmer amaranth has been confirmed in Nebraska and it is widespread in several counties. Soybean resistant to isoxaflutole/glufosinate/glyphosate has been developed that provides additional herbicide site of action for control of herbicide-resistant weeds. The objectives of this study were to evaluate herbicide programs for control of ALS inhibitor/GR Palmer amaranth and their effect on Palmer amaranth density and biomass, as well as soybean injury and yield in isoxaflutole/glufosinate/glyphosate-resistant soybean. Field experiments were conducted in a grower’s field infested with ALS inhibitor- and GR Palmer amaranth near Carleton, Nebraska, in 2018 and 2019. Isoxaflutole applied alone or mixed with sulfentrazone/pyroxasulfone, flumioxazin/pyroxasulfone, or imazethapyr/saflufenacil/pyroxasulfone provided similar control (86%-99%) of Palmer amaranth 21 d after PRE (DAPRE). At 14 d after early-POST (DAEPOST), isoxaflutole applied PRE and PRE followed by (fb) POST controlled Palmer amaranth 10% to 63% compared to 75% to 96% control with glufosinate applied EPOST in both years. A PRE herbicide fb glufosinate controlled Palmer amaranth 80% to 99% 21 d after late-POST (DALPOST) in 2018 and reduced density 89% to 100% in 2018 and 58% to 100% in 2019 at 14 DAEPOST. No soybean injury was observed from any of the herbicide programs tested in this study. Soybean yield in 2019 was relatively higher due to higher precipitation compared with 2018 with generally no differences between herbicide programs. This research indicates that herbicide programs are available for effective control of ALS inhibitor/GR Palmer amaranth in isoxaflutole/glufosinate/glyphosate-resistant soybean.

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Combined Effects of Acetolactate Synthase-Inhibiting Herbicides with Terbufos and Piperonyl Butoxide on Corn (Zea mays) and Soybean (Glycine max)

Weed Technology ◽

10.1017/s0890037x00024076 ◽

1995 ◽

Vol 9 (4) ◽

pp. 696-702 ◽

Cited By ~ 6

Author(s):

Chae Soon Kwon ◽

James J. Kells ◽

Donald Penner

Keyword(s):

Combination Treatment ◽

Field Experiments ◽

Acetolactate Synthase ◽

Field Studies ◽

Piperonyl Butoxide ◽

Corn Hybrids ◽

Combination Treatments ◽

Imidazolinone Herbicides ◽

Als Inhibitor ◽

Corn Hybrid

Greenhouse studies were conducted to determine the response of six corn hybrids and two soybean varieties to acetolactate synthase (ALS) inhibitor herbicides applied with terbufos and/or piperonyl butoxide (PBO), a mixed function oxidase (MFO) inhibitor. Field experiments also were conducted to determine the response of six corn hybrids to the combination treatments, terbufos plus ALS inhibitor herbicides and/or PBO and/or antidote. PBO at 0.33 kg/ha tank-mixed with nicosulfuron and primisulfuron injured the Northrup King 9283 corn hybrid. Great Lakes 584 corn was less sensitive than Northrup King 9283 to these combination treatments. Pioneer 3377 IR corn hybrid was resistant to the combination of nicosulfuron or primisulfuron plus PBO at 2 kg/ha and also to the combination treatments of imazethapyr herbicide plus PBO even though terbufos was previously applied. ICI 8532 IT, ICI 8532, and Pioneer 3377 hybrids were injured by the combination of nicosulfuron or primisulfuron and/or terbufos and/or PBO at 2 kg/ha. ICI 8532 IT corn hybrid was not injured by the combination treatment of imazethapyr or thifensulfuron and terbufos. In the field studies, Pioneer 3377 IR and Ciba 4393 RSC hybrids were resistant to sulfonylurea and imidazolinone herbicides even when applied with PBO regardless of the presence of terbufos. All treatments of chlorimuron plus terbufos caused considerable injury to ICI 8532 IT, ICI 8532, Pioneer 3377, and Ciba 4393, but not Pioneer 3377 IR and Ciba 4393 RSC. The combination of thifensulfuron with PBO injured Elgin ‘87 soybean, but the W20 soybean was tolerant to this combination treatment. Combination of imazethapyr with PBO did not affect the growth of Elgin ‘87 soybean.

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Acetolactate Synthase Inhibitor–Resistant False Cleavers (Galium spurium) in Western Canada

Weed Technology ◽

10.1614/wt-d-11-00075.1 ◽

2012 ◽

Vol 26 (1) ◽

pp. 151-155 ◽

Cited By ~ 11

Author(s):

Hugh J. Beckie ◽

Suzanne I. Warwick ◽

Connie A. Sauder ◽

Gina M. Kelln ◽

Chris Lozinski

Keyword(s):

Point Mutations ◽

Low Frequency ◽

Acetolactate Synthase ◽

Western Canada ◽

Resistance Factors ◽

Als Inhibitors ◽

Synthase Inhibitor ◽

Inhibitor Resistance ◽

Als Inhibitor ◽

Galium Spurium

Cleavers species (false cleavers and catchweed bedstraw) are among the top 10 most abundant weeds across the prairie region of western Canada, and are increasing in relative abundance at the fastest rate since the 1970s. In 2008, two false cleavers populations from Tisdale and Choiceland, Saskatchewan, were suspected of acetolactate synthase (ALS) –inhibitor resistance. Dose-response experiments were conducted with the use of imazethapyr and florasulam, both ALS inhibitors, as well as fluroxypyr, a synthetic auxin. Additionally, a 1,954–base-pair region of theALSgene including sites known to conferALSresistance were sequenced. Both populations were highly resistant to imazethapyr (resistance factors greater than 100), one population (Tisdale) was highly resistant to florasulam (Choiceland population susceptible, although a second, larger screening of 200 individuals indicated low frequency [2%] florasulam resistance), and both populations were susceptible to fluroxypyr. All sequenced Tisdale individuals screened with imazethapyr posessed the Trp574Leu mutation. In contrast, three point mutations were found for Choiceland individuals sequenced: Ser653Asn, Trp574Leu, and Asp376Glu. TheseALStarget-site mutations have not been documented previously in this species.

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Efficacy of Fall- and Spring-Applied Pyroxasulfone For Herbicide-Resistant Weeds in Field Pea

Weed Technology ◽

10.1614/wt-d-13-00140.1 ◽

2014 ◽

Vol 28 (2) ◽

pp. 351-360 ◽

Cited By ~ 9

Author(s):

Breanne D. Tidemann ◽

Linda M. Hall ◽

Eric N. Johnson ◽

Hugh J. Beckie ◽

Ken L. Sapsford ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Organic Matter Content ◽

Acetolactate Synthase ◽

Field Trials ◽

Matter Content ◽

Field Pea ◽

Wild Oat ◽

Herbicide Activity ◽

Als Inhibitor

Field trials were initiated in fall 2011 to determine the potential of pyroxasulfone to control acetolactate synthase (ALS) inhibitor-resistant weeds in field pea. Pyroxasulfone was applied in split-plot trials at five locations in western Canada using fall and PRE spring applications of 0 to 400 g ai ha−1. Trial locations were chosen with a range of soil organic matter content: 2.9, 4.3, 5.5, 10.5, and 10.6% at Scott, Kernen, Kinsella, Melfort, and Ellerslie, respectively. The herbicide dose required to reduce biomass by 50% (ED50) in false cleavers ranged between 53 and 395 g ha−1at Scott and Ellerslie, respectively. Wild oat ED50s varied between 0.54 g ha−1at Scott in the fall and 410 g ai ha−1in the spring at Melfort. ED50s for wild oat and false cleavers varied by 7.4- and 746-fold, respectively, depending primarily on the organic matter content at the trial location. The effect of application timing was not consistent. Significant yield reductions and pea injury occurred at 150 and 100 g ha−1and higher at Kernen and Scott, respectively. Low organic matter and high precipitation levels at these locations indicates increased herbicide activity under these conditions. Pyroxasulfone may allow control of ALS inhibitor-resistant false cleavers and wild oat; however, locations with high soil organic matter will require higher rates than those with low organic matter for similar control levels.

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Negative Cross-Resistance of Acetolactate Synthase Inhibitor–Resistant Kochia (Kochia scoparia) to Protoporphyrinogen Oxidase– and Hydroxyphenylpyruvate Dioxygenase–Inhibiting Herbicides

Weed Technology ◽

10.1614/wt-d-12-00020.1 ◽

2012 ◽

Vol 26 (3) ◽

pp. 570-574 ◽

Cited By ~ 3

Author(s):

Hugh J. Beckie ◽

Eric N. Johnson ◽

Anne Légère

Keyword(s):

Growth And Development ◽

Null Hypothesis ◽

Acetolactate Synthase ◽

Pleiotropic Effect ◽

Cross Resistance ◽

Kochia Scoparia ◽

Protoporphyrinogen Oxidase ◽

Synthase Inhibitor ◽

Sites Of Action ◽

Als Inhibitor

This greenhouse experiment examined the response of homozygous susceptible and acetolactate synthase (ALS) inhibitor–resistant plants from six Canadian kochia accessions with the Pro197 or Trp574 mutation to six alternative herbicides of different sites of action. The null hypothesis was ALS-inhibitor–resistant and –susceptible plants from within and across accessions would respond similarly to herbicides of different sites of action. This hypothesis was accepted for all accessions except that of MBK2 with the Trp574 mutation. Resistant plants of that accession were 80, 60, and 50% more sensitive than susceptible plants to pyrasulfotole, mesotrione (hydroxyphenylpyruvate dioxygenase [HPPD] inhibitors), and carfentrazone (protoporphyrinogen oxidase [PPO] inhibitor), respectively. However, no differential dose response between resistant and susceptible plants of this kochia accession to bromoxynil, fluroxypyr, or glyphosate was observed. A previous study had found marked differences in growth and development between resistant and susceptible plants of this accession, but not of the other accessions examined in this experiment. Negative cross-resistance exhibited by resistant plants of accession MBK2 to PPO and HPPD inhibitors in this experiment may be a pleiotropic effect related to the Trp574 mutation.

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Herbicide diagnostics reveal multiple patterns of synthetic auxin resistance in kochia (Bassia scoparia)

Weed Technology ◽

10.1017/wet.2021.69 ◽

2021 ◽

pp. 1-28

Author(s):

Charles M. Geddes ◽

Mallory L. Owen ◽

Teandra E. Ostendorf ◽

Julia Y. Leeson ◽

Shaun M. Sharpe ◽

...

Keyword(s):

Great Plains ◽

Dose Response ◽

Weed Management ◽

Acetolactate Synthase ◽

The United States ◽

Cross Resistance ◽

Visible Injury ◽

Synthetic Auxin ◽

Auxin Resistance ◽

Sites Of Action

Abstract Herbicide-resistant (HR) kochia is a growing problem in the Great Plains region of Canada and the United States (U.S.). Resistance to up to four herbicide sites of action, including photosystem II inhibitors, acetolactate synthase inhibitors, synthetic auxins, and the 5-enolpyruvylshikimate-3-phosphate synthase inhibitor glyphosate have been reported in many areas of this region. Despite being present in the U.S. since 1993/1994, auxinic-HR kochia is a recent and growing phenomenon in Canada. This study was designed to characterize (a) the level of resistance and (b) patterns of cross-resistance to dicamba and fluroxypyr in 12 putative auxinic-HR kochia populations from western Canada. The incidence of dicamba-resistant individuals ranged among populations from 0% to 85%, while fluroxypyr-resistant individuals ranged from 0% to 45%. In whole-plant dose-response bioassays, the populations exhibited up to 6.5-fold resistance to dicamba and up to 51.5-fold resistance to fluroxypyr based on visible injury 28 days after application. Based on plant survival estimates, the populations exhibited up to 3.7-fold resistance to dicamba and up to 72.5-fold resistance to fluroxypyr. Multiple patterns of synthetic auxin resistance were observed, where one population from Cypress County, Alberta was resistant to dicamba but not fluroxypyr, while another from Rocky View County, Alberta was resistant to fluroxypyr but not dicamba based on single-dose population screening and dose-response bioassays. These results suggest that multiple mechanisms may confer resistance to dicamba and/or fluroxypyr in Canadian kochia populations. Further research is warranted to determine these mechanisms. Farmers are urged to adopt proactive non-chemical weed management tools in an effort to preserve efficacy of the remaining herbicide options available for control of HR kochia.

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Acetolactate synthase inhibitor-resistant stinkweed (Thlaspi arvense L.) in Alberta

Canadian Journal of Plant Science ◽

10.4141/cjps06019 ◽

2007 ◽

Vol 87 (4) ◽

pp. 965-972 ◽

Cited By ~ 14

Author(s):

H. J. Beckie ◽

L. M. Hall ◽

F. J. Tardif ◽

G. Séguin-Swartz

Keyword(s):

Herbicide Resistance ◽

Dominant Gene ◽

Acetolactate Synthase ◽

Target Site ◽

Cross Resistance ◽

Resistance Pattern ◽

Site Mutation ◽

Thlaspi Arvense ◽

Synthase Inhibitor ◽

Als Inhibitor

Two stinkweed populations from southern and central Alberta were not controlled by acetolactate synthase (ALS)-inhibiting herbicides in 2000. This study reports on their cross-resistance to ALS-inhibiting herbicides, molecular basis of resistance, and inheritance of resistance. Both putative herbicide-resistant biotypes responded similarly to increasing doses of the herbicides. The biotypes were highly resistant to ethametsulfuron and exhibited a low level of resistance to metsulfuron and imazethapyr. However, both biotypes were not resistant to florasulam, a triazolopyrimidine ALS inhibitor, or sulfometuron, a non-selective sulfonylurea ALS inhibitor. The cross-resistance pattern was consistent with the confirmed target-site mutation. Sequence analysis of the ALS gene detected a Pro197Leu mutation in both biotypes. Similar to many other ALS inhibitor-resistant weed biotypes, resistance was conferred by a single dominant gene. This study confirms the first global occurrence of herbicide resistance in this species. Key words: ALS-inhibitor resistance, ALS sequence, herbicide resistance, target-site mutation

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Interspecific Hybridization: Potential for Movement of Herbicide Resistance from Wheat to Jointed Goatgrass (Aegilops cylindrica)

Weed Technology ◽

10.1614/wt-04-217r.1 ◽

2005 ◽

Vol 19 (3) ◽

pp. 674-682 ◽

Cited By ~ 28

Author(s):

Bradley D. Hanson ◽

Carol A. Mallory-Smith ◽

William J. Price ◽

Bahman Shafii ◽

Donald C. Thill ◽

...

Keyword(s):

Pacific Northwest ◽

Great Plains ◽

Herbicide Resistance ◽

Field Experiments ◽

Introgressive Hybridization ◽

Acetolactate Synthase ◽

The United States ◽

Aegilops Cylindrica ◽

Herbicide Resistant ◽

Jointed Goatgrass

The transfer of herbicide resistance genes from crops to related species is one of the greatest risks of growing herbicide-resistant crops. The recent introductions of imidazolinone-resistant wheat in the Great Plains and Pacific Northwest regions of the United States and research on transgenic glyphosate-resistant wheat have raised concerns about the transfer of herbicide resistance from wheat to jointed goatgrass via introgressive hybridization. Field experiments were conducted from 2000 to 2003 at three locations in Washington and Idaho to determine the frequency and distance that imidazolinone-resistant wheat can pollinate jointed goatgrass and produce resistant F1hybrids. Each experiment was designed as a Nelder wheel with 16 equally spaced rays extending away from a central pollen source of ‘Fidel-FS4’ imidazolinone-resistant wheat. Each ray was 46 m long and contained three rows of jointed goatgrass. Spikelets were collected at maturity at 1.8-m intervals along each ray and subjected to an imazamox screening test. The majority of all jointed goatgrass seeds tested were not resistant to imazamox; however, 5 and 15 resistant hybrids were found at the Pullman, WA, and Lewiston, ID, locations, respectively. The resistant plants were identified at a maximum distance of 40.2 m from the pollen source. The overall frequency of imazamox-resistant hybrids was similar to the predicted frequency of naturally occurring acetolactate synthase resistance in weeds; however, traits with a lower frequency of spontaneous mutations may have a relatively greater risk for gene escape via introgressive hybridization.

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Comparison of Herbicide Programs for Season-Long Control of Glyphosate-Resistant Common Waterhemp (Amaranthus rudis) in Soybean

Weed Technology ◽

10.1017/wet.2016.1 ◽

2017 ◽

Vol 31 (1) ◽

pp. 53-66 ◽

Cited By ~ 19

Author(s):

Debalin Sarangi ◽

Lowell D. Sandell ◽

Greg R. Kruger ◽

Stevan Z. Knezevic ◽

Suat Irmak ◽

...

Keyword(s):

Field Experiments ◽

Acetolactate Synthase ◽

Growing Season ◽

Soybean Field ◽

Common Waterhemp ◽

Need To Evaluate ◽

Amaranthus Rudis ◽

Reduced Density ◽

Als Inhibitor ◽

Herbicide Programs

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.

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Response of Acetolactate Synthase–Resistant Grain Sorghum to Nicosulfuron Plus Rimsulfuron

Weed Technology ◽

10.1614/wt-d-09-00061.1 ◽

2010 ◽

Vol 24 (4) ◽

pp. 411-415 ◽

Cited By ~ 5

Author(s):

D. Shane Hennigh ◽

Kassim Al-Khatib ◽

Mitchell R. Tuinstra

Keyword(s):

Grain Yield ◽

Plant Height ◽

Field Experiments ◽

Acetolactate Synthase ◽

Grain Sorghum ◽

Yield Reduction ◽

Growth Stages ◽

Visible Injury ◽

Leaf Stage ◽

Sorghum Grain

The lack of POST herbicides to control grasses in grain sorghum prompted researchers to develop acetolactate synthase (ALS)–resistant grain sorghum. Field experiments were conducted to evaluate the differential response of ALS-resistant grain sorghum to POST application of nicosulfuron + rimsulfuron applied at three growth stages. ALS-resistant grain sorghum was treated with 0, 13 + 7, 26 + 13, 39 + 20, 52 + 26, 65 + 33, 78 + 39, and 91 + 46 g ai ha−1of nicosulfuron + rimsulfuron when plants were at the three- to five-leaf, seven- to nine-leaf, or 11- to 13-leaf stage. In general, as nicosulfuron + rimsulfuron rates increased, visible injury increased at the three- to five-leaf and seven- to nine-leaf stages. Injury was greatest 1 wk after treatment for the three- to five-leaf and seven- to nine-leaf stages across all ratings, and plants then began to recover. No injury was observed at any rating time for the 11- to 13-leaf stage. Plant height and sorghum grain yield were reduced as nicosulfuron + rimsulfuron rates increased when applied at the three- to five-leaf stage. However, nicosulfuron + rimsulfuron applied at the seven- to nine-leaf and 11- to 13-leaf stages did not decrease sorghum yield. This research indicated that nicosulfuron + rimsulfuron application at the three- to five-leaf stage injured ALS-resistant grain sorghum; however, application at the seven- to nine-leaf or 11- to 13-leaf stages did not result in grain yield reduction.

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