Control and Cross-Resistance of an Acetolactate Synthase Inhibitor-Resistant Palmer Amaranth (Amaranthus palmeri) Biotype

1997 ◽  
Vol 11 (1) ◽  
pp. 132-137 ◽  
Author(s):  
Jason W. Gaeddert ◽  
Dallas E. Peterson ◽  
Michael J. Horak
Keyword(s):  
Rate Control ◽  
Cultural Practices ◽  
Acetolactate Synthase ◽  
Mechanisms Of Action ◽  
Palmer Amaranth ◽  
Cross Resistance ◽  
Amaranthus Palmeri ◽  
Partial Control ◽  
Synthase Inhibitor ◽  
Control Tank

Over two years, acetolactate synthase (ALS)-inhibiting herbicides and herbicides with different mechanisms of action were tested individually and in combination for control of ALS-resistant Palmer amaranth in soybean. As expected, ALS-inhibiting herbicides did not control the resistant Palmer amaranth. Lactofen at 210 g/ha and acifluorfen at 560 g/ha gave the best postemergence control. Tank mixes of lactofen with either imazethapyr or chlorimuron plus thifensulfuron did not significantly increase control over lactofen alone. Sequential treatment with a soil-applied herbicide, either SAN 582 or pendimethalin, followed by lactofen postemergence, controlled weeds best (greater than 85%). The extent of cross-resistance of Palmer amaranth to ALS-inhibiting herbicides was determined in the greenhouse. Sixteen POST ALS-inhibiting herbicides were sprayed at ½, 1, 2, 4, and 8X field use rates on resistant and susceptible biotypes. All ALS-inhibiting herbicides at all rates controlled the susceptible biotype. The resistant biotype was cross-resistant to all ALS-inhibiting herbicides. Metsulfuron and imazapyr at 8X rates were the only treatments that provided 80% or greater control of the ALS-resistant Palmer amaranth. Chlorsulfuron and tribenuron were the only other herbicides that gave partial control at the highest rate. Control with these four herbicides decreased as the rate was decreased. Experimental results suggest that cultural practices and herbicides with different mechanisms of action will be required to manage this ALS-resistant Palmer amaranth biotype.

scholarly journals Confirmation of S-metolachlor resistance in Palmer amaranth (Amaranthus palmeri)

2019 ◽  
Vol 33 (5) ◽  
pp. 720-726 ◽  
Author(s):  
Chad Brabham ◽  
Jason K. Norsworthy ◽  
Michael M. Houston ◽  
Vijay K Varanasi ◽  
Tom Barber
Keyword(s):  
Dose Response ◽  
Resistance Mechanism ◽  
Acetolactate Synthase ◽  
Chain Fatty Acid ◽  
Palmer Amaranth ◽  
Cross Resistance ◽  
Amaranthus Palmeri ◽  
Glutathione S Transferase ◽  
Long Chain Fatty Acid ◽  
Long Chain

AbstractS-Metolachlor is commonly used by soybean and cotton growers, especially with POST treatments for overlapping residuals, to obtain season-long control of glyphosate- and acetolactate synthase (ALS)–resistant Palmer amaranth. In Crittenden County, AR, reports of Palmer amaranth escapes following S-metolachlor treatment were first noted at field sites near Crawfordsville and Marion in 2016. Field and greenhouse experiments were conducted to confirm S-metolachlor resistance and to test for cross-resistance to other very-long-chain fatty acid (VLCFA)–inhibiting herbicides in Palmer amaranth accessions from Crawfordsville and Marion. Palmer amaranth control in the field (soil <3% organic matter) 14 d after treatment (DAT) was ≥94% with a 1× rate of acetochlor (1,472 g ai ha–1; emulsifiable concentrate formulation) and dimethenamid-P (631 g ai ha–1). However, S-metolachlor at 1,064 g ai ha–1 provided only 76% control, which was not significantly different from the 1/2× and 1/4× rates of dimethenamid-P and acetochlor (66% to 85%). In the greenhouse, Palmer amaranth accessions from Marion and Crawfordsville were 9.8 and 8.3 times more resistant to S-metolachlor compared with two susceptible accessions based on LD50 values obtained from dose–response experiments. Two-thirds and 1.5 times S-metolachlor at 1,064 g ha–1 were the estimated rates required to obtain 90% mortality of the Crawfordsville and Marion accessions, respectively. Data collected from the field and greenhouse confirm that these accessions have evolved a low level of resistance to S-metolachlor. In an agar-based assay, the level of resistance in the Marion accession was significantly reduced in the presence of a glutathione S-transferase (GST) inhibitor, suggesting that GSTs are the probable resistance mechanism. With respect to other VLCFA-inhibiting herbicides, Marion and Crawfordsville accessions were not cross-resistant to acetochlor, dimethenamid-P, or pyroxasulfone. However, both accessions, based on LD50 values obtained from greenhouse dose–response experiments, exhibited reduced sensitivity (1.5- to 3.6-fold) to the tested VLCFA-inhibiting herbicides.

Palmer amaranth (Amaranthus palmeri) and common waterhemp (Amaranthus rudis) resistance to selected ALS-inhibiting herbicides

Weed Science ◽  
1997 ◽  
Vol 45 (2) ◽  
pp. 192-197 ◽  
Author(s):  
Christy L. Sprague ◽  
Edward W. Stoller ◽  
Loyd M. Wax ◽  
Michael J. Horak
Keyword(s):  
Acetolactate Synthase ◽  
Palmer Amaranth ◽  
Cross Resistance ◽  
Amaranthus Palmeri ◽  
Sulfonylurea Herbicides ◽  
Common Waterhemp ◽  
Whole Plant ◽  
Amaranthus Rudis

Imazethapyr-resistant biotypes of Palmer amaranth and common waterhemp were studied to determine the magnitude of resistance and cross-resistance to three acetolactate synthase (ALS)-inhibiting herbicides. Resistant biotypes of Palmer amaranth and common waterhemp demonstrated > 2,800- and > 130-fold resistance to phytotoxicity of imazethapyr compared to susceptible biotypes, respectively. Concentrations of imazethapyr required for 50% in vivo inhibition of ALS activity were at least > 13,100 and > 1,900 times greater for resistant biotypes of Palmer amaranth and common waterhemp, respectively, compared to susceptible plants. Resistant biotypes of both species demonstrated cross-resistance to the sulfonylurea herbicides thifensulfuron and chlorimuron at the whole plant and enzyme levels, indicating that a less sensitive ALS enzyme confers this resistance to these plants.

Palmer Amaranth (Amaranthus palmeri) Control by Glufosinate plus Fluometuron Applied Postemergence to WideStrike®Cotton

2013 ◽  
Vol 27 (2) ◽  
pp. 291-297 ◽  
Author(s):  
Kelly A. Barnett ◽  
A. Stanley Culpepper ◽  
Alan C. York ◽  
Lawrence E. Steckel
Keyword(s):  
United States ◽  
Weed Control ◽  
Acetolactate Synthase ◽  
The United States ◽  
Palmer Amaranth ◽  
Effective Control ◽  
Yield Response ◽  
Amaranthus Palmeri ◽  
Cotton Yield ◽  
Cotton Cultivar

Glyphosate-resistant (GR) weeds, especially GR Palmer amaranth, are very problematic for cotton growers in the Southeast and Midsouth regions of the United States. Glufosinate can control GR Palmer amaranth, and growers are transitioning to glufosinate-based systems. Palmer amaranth must be small for consistently effective control by glufosinate. Because this weed grows rapidly, growers are not always timely with applications. With widespread resistance to acetolactate synthase-inhibiting herbicides, growers have few herbicide options to mix with glufosinate to improve control of larger weeds. In a field study using a WideStrike®cotton cultivar, we evaluated fluometuron at 140 to 1,120 g ai ha−1mixed with the ammonium salt of glufosinate at 485 g ae ha−1for control of GR Palmer amaranth 13 and 26 cm tall. Standard PRE- and POST-directed herbicides were included in the systems. Glufosinate alone injured the WideStrike® cotton less than 10%. Fluometuron increased injury up to 25% but did not adversely affect yield. Glufosinate controlled 13-cm Palmer amaranth at least 90%, and there was no improvement in weed control nor a cotton yield response to fluometuron mixed with glufosinate. Palmer amaranth 26 cm tall was controlled only 59% by glufosinate. Fluometuron mixed with glufosinate increased control of the larger weeds up to 28% and there was a trend for greater yields. However, delaying applications until weeds were 26 cm reduced yield 22% relative to timely application. Our results suggest fluometuron mixed with glufosinate may be of some benefit when attempting to control large Palmer amaranth. However, mixing fluometuron with glufosinate is not a substitute for a timely glufosinate application.

Susceptibility of Palmer amaranth (Amaranthus palmeri) to herbicides in accessions collected from the North Carolina Coastal Plain

Weed Science ◽  
2020 ◽  
Vol 68 (6) ◽  
pp. 582-593
Author(s):  
Denis J. Mahoney ◽  
David L. Jordan ◽  
Nilda Roma-Burgos ◽  
Katherine M. Jennings ◽  
Ramon G. Leon ◽  
...  
Keyword(s):  
North Carolina ◽  
Dose Response ◽  
Coastal Plain ◽  
Weed Management ◽  
Acetolactate Synthase ◽  
Fold Increase ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Sites Of Action ◽  
Two Populations

AbstractPalmer amaranth (Amaranthus palmeri S. Watson) populations resistant to acetolactate synthase (ALS)-inhibiting herbicides and glyphosate are fairly common throughout the state of North Carolina (NC). This has led farm managers to rely more heavily on herbicides with other sites of action (SOA) for A. palmeri control, especially protoporphyrinogen oxidase and glutamine synthetase inhibitors. In the fall of 2016, seeds from A. palmeri populations were collected from the NC Coastal Plain, the state’s most prominent agricultural region. In separate experiments, plants with 2 to 4 leaves from the 110 populations were treated with field use rates of glyphosate, glufosinate-ammonium, fomesafen, mesotrione, or thifensulfuron-methyl. Percent visible control and survival were evaluated 3 wk after treatment. Survival frequencies were highest following glyphosate (99%) or thifensulfuron-methyl (96%) treatment. Known mutations conferring resistance to ALS inhibitors were found in populations surviving thifensulfuron-methyl application (Ala-122-Ser, Pro-197-Ser, Trp-574-Leu, and/or Ser-653-Asn), in addition to a new mutation (Ala-282-Asp) that requires further investigation. Forty-two populations had survivors after mesotrione application, with one population having 17% survival. Four populations survived fomesafen treatment, while none survived glufosinate. Dose–response studies showed an increase in fomesafen needed to kill 50% of two populations (LD50); however, these rates were far below the field use rate (less than 5 g ha−1). In two populations following mesotrione dose–response studies, a 2.4- to 3.3-fold increase was noted, with LD90 values approaching the field use rate (72.8 and 89.8 g ha−1). Screening of the progeny of individuals surviving mesotrione confirmed the presence of resistance alleles, as there were a higher number of survivors at the 1X rate compared with the parent population, confirming resistance to mesotrione. These data suggest A. palmeri resistant to chemistries other than glyphosate and thifensulfuron-methyl are present in NC, which highlights the need for weed management approaches to mitigate the evolution and spread of herbicide-resistant populations.

Palmer Amaranth (Amaranthus palmeri) Management in Dicamba-Resistant Cotton

2015 ◽  
Vol 29 (4) ◽  
pp. 758-770 ◽  
Author(s):  
Charles W. Cahoon ◽  
Alan C. York ◽  
David L. Jordan ◽  
Wesley J. Everman ◽  
Richard W. Seagroves ◽  
...  
Keyword(s):  
United States ◽  
North Carolina ◽  
Field Experiment ◽  
Acetolactate Synthase ◽  
The United States ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Cotton Yield ◽  
Herbicide Resistant

Cotton growers rely heavily upon glufosinate and various residual herbicides applied preplant, PRE, and POST to control Palmer amaranth resistant to glyphosate and acetolactate synthase-inhibiting herbicides. Recently deregulated in the United States, cotton resistant to dicamba, glufosinate, and glyphosate (B2XF cotton) offers a new platform for controlling herbicide-resistant Palmer amaranth. A field experiment was conducted in North Carolina and Georgia to determine B2XF cotton tolerance to dicamba, glufosinate, and glyphosate and to compare Palmer amaranth control by dicamba to a currently used, nondicamba program in both glufosinate- and glyphosate-based systems. Treatments consisted of glyphosate or glufosinate applied early POST (EPOST) and mid-POST (MPOST) in a factorial arrangement of treatments with seven dicamba options (no dicamba, PRE, EPOST, MPOST, PRE followed by [fb] EPOST, PRE fb MPOST, and EPOST fb MPOST) and a nondicamba standard. The nondicamba standard consisted of fomesafen PRE, pyrithiobac EPOST, and acetochlor MPOST. Dicamba caused no injury when applied PRE and only minor, transient injury when applied POST. At time of EPOST application, Palmer amaranth control by dicamba or fomesafen applied PRE, in combination with acetochlor, was similar and 13 to 17% greater than acetochlor alone. Dicamba was generally more effective on Palmer amaranth applied POST rather than PRE, and two applications were usually more effective than one. In glyphosate-based systems, greater Palmer amaranth control and cotton yield were obtained with dicamba applied EPOST, MPOST, or EPOST fb MPOST compared with the standard herbicides in North Carolina. In contrast, dicamba was no more effective than the standard herbicides in the glufosinate-based systems. In Georgia, dicamba was as effective as the standard herbicides in a glyphosate-based system only when dicamba was applied EPOST fb MPOST. In glufosinate-based systems in Georgia, dicamba was as effective as standard herbicides only when dicamba was applied twice.

scholarly journals Interference of Selected Palmer Amaranth (Amaranthus palmeri) Biotypes in Soybean (Glycine max)

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Aman Chandi ◽  
David L. Jordan ◽  
Alan C. York ◽  
Susana R. Milla-Lewis ◽  
James D. Burton ◽  
...  
Keyword(s):  
Glycine Max ◽  
Acetolactate Synthase ◽  
Dry Weight ◽  
Glyphosate Resistance ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Fresh Weight ◽  
Row Crops ◽  
Soybean Yield ◽  
Competitive Disadvantage

Palmer amaranth (Amaranthus palmeriS. Wats.) has become difficult to control in row crops due to selection for biotypes that are no longer controlled by acetolactate synthase inhibiting herbicides and/or glyphosate. Early season interference in soybean [Glycine max(L.) Merr.] for 40 days after emergence by three glyphosate-resistant (GR) and three glyphosate-susceptible (GS) Palmer amaranth biotypes from Georgia and North Carolina was compared in the greenhouse. A field experiment over 2 years compared season-long interference of these biotypes in soybean. The six Palmer amaranth biotypes reduced soybean height similarly in the greenhouse but did not affect soybean height in the field. Reduction in soybean fresh weight and dry weight in the greenhouse; and soybean yield in the field varied by Palmer amaranth biotypes. Soybean yield was reduced 21% by Palmer amaranth at the established field density of 0.37 plant m−2. When Palmer amaranth biotypes were grouped by response to glyphosate, the GS group reduced fresh weight, dry weight, and yield of soybean more than the GR group. The results indicate a possible small competitive disadvantage associated with glyphosate resistance, but observed differences among biotypes might also be associated with characteristics within and among biotypes other than glyphosate resistance.

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

2012 ◽  
Vol 26 (3) ◽  
pp. 570-574 ◽  
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.

scholarly journals Evaluation of Preemergence Herbicide Programs for Control of Protoporphyrinogen Oxidase-Resistant Amaranthus palmeri in Soybean

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Michael M. Houston ◽  
L. Tom Barber ◽  
Jason K. Norsworthy ◽  
Trent L. Roberts
Keyword(s):  
Acetolactate Synthase ◽  
Field Trials ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Long Chain Fatty Acid ◽  
Protoporphyrinogen Oxidase ◽  
Density Reduction ◽  
Glycine Max L ◽  
Sites Of Action ◽  
Herbicide Programs

Protoporphyrinogen oxidase- (PPO-) resistant Amaranthus palmeri (S.) Wats. (Palmer amaranth) was confirmed in Arkansas in 2015. Field trials were conducted in Crawfordsville, Gregory, and Marion, Arkansas in 2016, and Crawfordsville and Marion in 2017, assessing PPO-resistant Palmer amaranth control options in Glycine max (L.) Merr. (soybean). Twelve trials consisted of 26 preemergence (PRE) treatments, evaluated for Palmer amaranth control and density reduction at 28 days after treatment (DAT). Treatments that consisted of PPO- or acetolactate synthase- (ALS-) inhibiting herbicides such as flumioxazin (72 g ai ha−1) or sulfentrazone + cloransulam (195 g ha−1 + 25 g ha−1) controlled Palmer amaranth <60%. At 28 DAT, treatments including mixtures of a very-long-chain fatty acid (VLCFA) plus the photosystem II- (PSII-) inhibiting herbicide metribuzin provided increased control over single herbicide sites of action (SOA) or herbicides mixtures to which Palmer amaranth was resistant. Pyroxasulfone + metribuzin (149 g ha−1 + 314 g ha−1) controlled Palmer amaranth 91% control across twelve trials at 28 DAT. S-metolachlor alone did not provide consistent, acceptable control of PPO-resistant Palmer amaranth (55–77%); subsequent research has determined that these populations are resistant to S-metolachlor. A minimum of two effective herbicides should be included in soybean PRE programs for control of PPO-resistant Palmer amaranth.

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

2007 ◽  
Vol 87 (4) ◽  
pp. 965-972 ◽  
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

Confirmation and Control of Triazine and 4-Hydroxyphenylpyruvate Dioxygenase-Inhibiting Herbicide-Resistant Palmer Amaranth (Amaranthus palmeri) in Nebraska

2014 ◽  
Vol 28 (1) ◽  
pp. 28-38 ◽  
Author(s):  
Amit J. Jhala ◽  
Lowell D. Sandell ◽  
Neha Rana ◽  
Greg R. Kruger ◽  
Stevan Z. Knezevic
Keyword(s):  
Acetolactate Synthase ◽  
The United States ◽  
Oxidase Inhibitor ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Corn Production ◽  
Herbicide Resistant ◽  
South Central ◽  
Fold Level ◽  
And Control

Palmer amaranth is a difficult-to-control broadleaf weed that infests corn and soybean fields in south-central and southwestern Nebraska and several other states in the United States. The objectives of this research were to confirm triazine and 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide-resistant Palmer amaranth in Nebraska and to determine sensitivity and efficacy of POST-applied corn herbicides for control of resistant and susceptible Palmer amaranth biotypes. Seeds from a putative HPPD-resistant Palmer amaranth biotype from Fillmore County, NE were collected from a seed corn production field in fall 2010. The response of Palmer amaranth biotypes to 12 rates (0 to 12×) of mesotrione, tembotrione, topramezone, and atrazine was evaluated in a dose–response bioassay in a greenhouse. On the basis of the values at the 90% effective dose (ED90) level, the analysis showed a 4- to 23-fold resistance depending upon the type of HPPD-inhibiting herbicide being investigated and susceptible biotype used for comparison. This biotype also had a 9- to 14-fold level of resistance to atrazine applied POST. Results of a POST-applied herbicide efficacy study suggested a synergistic interaction between atrazine and HPPD-inhibiting herbicides that resulted in > 90% control of all Palmer amaranth biotypes. The resistant biotype had a reduced sensitivity to acetolactate synthase inhibiting herbicides (halosulfuron and primisulfuron), a photosystem-II inhibitor (bromoxynil), and a protoporphyrinogen oxidase inhibitor (fluthiacet-methyl). Palmer amaranth biotypes were effectively controlled (≥ 90%) with glyphosate, glufosinate, and dicamba, whereas 2,4-D ester provided 81 to 83% control of the resistant biotype and > 90% control of both susceptible biotypes.

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