scholarly journals Herbicide resistance in the Canadian prairie provinces : Five years after the fact

2005 ◽  
Vol 75 (4) ◽  
pp. 5-16 ◽  
Author(s):  
I.N. Morrisson ◽  
M.D. Devine
Keyword(s):  
Herbicide Resistance ◽  
Effective Control ◽  
Cross Resistance ◽  
Multiple Resistance ◽  
Canadian Prairie ◽  
Wild Oats ◽  
Wild Mustard ◽  
Green Foxtail ◽  
Group 2 ◽  
Group 1

Herbicide resistance was first recognized as a problem on the Canadian Prairies in 1988 when trifluralin-resistant green foxtail (Setaria viridis) was reported in Manitoba, and chlorsulfuron-resistant chickweed (Stellaria media) and koehia (Kochia scoparia) in Alberta and Saskatchewan, respectively. Since then, the number of resistant weeds has increased to include wild oats (Avena fatua) resistant to triallate and to aryloxyphenoxypropionate and cyclohexanedione (group 1) herbicides, green foxtail to group 1 herbicides, Russian thistle (Salsola pestifer) and wild mustard (Sinapis arvensis) to sulfonylurea and imidazolinone (group 2) herbicides, and wild mustard to growth regulator (group 4) herbicides. The levels and patterns of cross-resistance to chemicals in groups 1 and 2 vary widely among different populations, with resistance factors [resistant to susceptible (R:S) ratios] derived from dose response curves typically ranging from < 2 to > 150. Group 1 resistance in green foxtail and group 2 resistance in chickweed and kochia populations are due to reduced sensitivities of the target enzymes, acetyl coenzyme-A carboxylase (ACCase) and acetolactate synthase (ALS), respectively. The mechanisms of resistance in the other species including wild oats resistant to ACCase inhibitors (group 1 ) and to triallate/difenzoquat (group 8) are unclear. At present, the only instance of multiple resistance in western Canada is green foxtail resistant to chemicals in both groups 1 and 3 (ACCase inhibitors and dinitroanilines). Future concerns focus mainly on the increasing seriousness of group 1 and 8 resistance across the Prairies, and on the possibility of selecting for multiple resistance in weeds such as green foxtail for which there are few remaining effective control options.

Herbicide-Resistant Weeds in the Canadian Prairies: 2007 to 2011

2013 ◽  
Vol 27 (1) ◽  
pp. 171-183 ◽  
Author(s):  
Hugh J. Beckie ◽  
Chris Lozinski ◽  
Scott Shirriff ◽  
Clark. A. Brenzil
Keyword(s):  
Acetolactate Synthase ◽  
Fold Increase ◽  
Wild Oat ◽  
Total Field ◽  
Herbicide Resistant ◽  
Wild Mustard ◽  
Green Foxtail ◽  
Group 2 ◽  
Field Area ◽  
Group 1

A late-summer survey of herbicide-resistant (HR) weeds was conducted in Alberta in 2007, Manitoba in 2008, and Saskatchewan in 2009, totaling 1,000 randomly selected annually cropped fields. In addition, we screened 1,091 weed seed samples (each sample from one field) submitted by Prairie growers between 2007 and 2011. Of 677 fields where wild oat samples were collected, 298 (44%) had an HR biotype. Group 1 (acetyl CoA carboxylase inhibitor)-HR wild oat was confirmed in 275 fields (41%), up from 15% in previous baseline surveys (2001 to 2003). Group 2 (acetolactate synthase)-HR wild oat was found in 12% of fields (vs. 8% in 2001 to 2003). Group 8 (triallate, difenzoquat)-HR wild oat was identified in only 8% of fields (not tested in 2001 to 2003); the frequency of occurrence of group 1+2-HR wild oat was similar (8%, vs. 3% in 2001 to 2003). Group 1-HR green foxtail was found in 27% of 209 fields sampled for the weed (vs. 6% in 2001 to 2003). Group 2-HR spiny sowthistle was confirmed in all Alberta fields sampled (vs. 67% in 2001); common chickweed was found mainly in Alberta in 40% of fields (vs. 17% in 2001). Group 2-HR weed biotypes not previously detected in the baseline surveys included false cleavers mainly in Alberta (17% of fields) and Saskatchewan (21%), Powell amaranth in Manitoba (16% of fields), wild mustard (three populations in Saskatchewan and Manitoba), and wild buckwheat (one population in Alberta). No sampled weed populations across the Prairies were found to be resistant to herbicides from group 4 (synthetic auxins), group 9 (glyphosate), or group 10 (glufosinate). Based on the proportion of total field area at each site infested with HR weeds, it is estimated that 7.7 million ha (29% of annually cropped land) are infested with HR weeds (eight-fold increase from 2001 to 2003), in a total field area of 9.9 million ha (37%)—over a two-fold increase. Of 816 cases of HR wild oat identified from submitted samples, 69% were group 1-HR, 15% group 2-HR, and 16% group 1+2-HR. Additionally, there were 10 populations of group 1-HR green foxtail in Saskatchewan or Manitoba, and six populations of group 1-HR Persian darnel in southern Alberta and Saskatchewan. Various group 2-HR broadleaf weeds were identified, including 17 wild mustard populations mainly from Saskatchewan and 39 cleavers populations across the three Prairie provinces. Herbicide-use data from 2006 to 2010 indicated continued reliance on group 1 herbicides in cereal crops and group 2 herbicides in pulse crops.

scholarly journals First Report on Assessing the Severity of Herbicide Resistance to ACCase Inhibitors Pinoxaden, Propaquizafop and Cycloxydim in Six Avena fatua Populations in Ireland

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1362
Author(s):  
Vijaya Bhaskar Alwarnaidu Vijayarajan ◽  
Patrick D. Forristal ◽  
Sarah K. Cook ◽  
Jimmy Staples ◽  
David Schilder ◽  
...  
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Avena Fatua ◽  
Crop Rotations ◽  
Effective Control ◽  
Cross Resistance ◽  
Variable Cross ◽  
Wild Oats ◽  
Rf Values ◽  
Susceptible Populations

In response to growers reports of poor weed control, resistance to ACCase inhibitors pinoxaden, propaquizafop and cycloxydim was investigated in populations of six wild oats, Avena fatua, collected from cereal-dominated crop rotations in Ireland. Glasshouse assays confirmed reduced sensitivity to all three ACCase inhibitors in four of the six populations, R2 to R5. R1 was cross-resistant to pinoxaden and propaquizafop and R6 was resistant to propaquizafop only. Dose-response studies confirmed significant differences in the severity of resistance amongst these populations (p < 0.05). For pinoxaden, the ED50 or GR50 resistance factor (RF) of R1, R3 and R5 were between 11.6 and 13.1 times or 25.1 and 30.2 times more resistant, respectively, compared with the susceptible populations. For propaquizafop, the ED50 and GR50 RF of R1, R2, R3, R5 and R6 were between >7.8 and >32 or 16.6 and 59 times more resistant, respectively. For cycloxydim, only R5 had both high ED50 and GR50 RF values of >43.2 and 98.4 respectively. In R2, although the ED50 values to both pinoxaden and cycloxydim and additionally, R3 to cycloxydim, were above recommended field rates, their GR50 values remained below, suggesting a shift towards cross-resistance. While R4 was the only population, where both ED50 and GR50 for all ACCase inhibitors remained below recommended field rates, they would not give effective control at these rates, strongly indicating evolving resistance. This is the first study reporting variable cross-resistance types and levels to ACCase inhibitors in A. fatua from Ireland.

Weed Resistance Monitoring in the Canadian Prairies

2008 ◽  
Vol 22 (3) ◽  
pp. 530-543 ◽  
Author(s):  
Hugh J. Beckie ◽  
Julia Y. Leeson ◽  
A. Gordon Thomas ◽  
Clark A. Brenzil ◽  
Linda M. Hall ◽  
...  
Keyword(s):  
Acetolactate Synthase ◽  
Resistance Testing ◽  
Cross Resistance ◽  
Northern Great Plains ◽  
Wild Oat ◽  
Resistance Monitoring ◽  
Green Foxtail ◽  
Group 2 ◽  
Weed Resistance ◽  
Group 1

Weed resistance monitoring has been routinely conducted in the Northern Great Plains of Canada (Prairies) since the mid-1990s. Most recently, random surveys were conducted in Alberta in 2001, Manitoba in 2002, and Saskatchewan in 2003 totaling nearly 800 fields. In addition, nearly 1,300 weed seed samples were submitted by growers across the Prairies between 1996 and 2006 for resistance testing. Collected or submitted samples were screened for group 1 [acetyl-CoA carboxylase (ACCase) inhibitor] and/or group 2 [acetolactate synthase (ALS) inhibitor] resistance. Twenty percent of 565 sampled fields had an herbicide-resistant (HR) wild oat biotype. Most populations exhibited broad cross-resistance across various classes of group 1 or group 2 herbicides. In Manitoba, 22% of 59 fields had group 1–HR green foxtail. Group 2–HR biotypes of kochia were documented in Saskatchewan, common chickweed and spiny sowthistle in Alberta, and green foxtail and redroot pigweed in Manitoba. Across the Prairies, HR weeds are estimated to occur in fields covering an area of nearly 5 million ha. Of 1,067 wild oat seed samples submitted by growers and industry for testing between 1996 and 2006, 725 were group 1 HR, 34 group 2 HR, and 55 groups 1 and 2 HR. Of 80 submitted green foxtail samples, 26 were confirmed group 1 HR; most populations originated from southern Manitoba where the weed is most abundant. Similar to the field surveys, various group 2–HR biotypes were confirmed among submitted samples: kochia, wild mustard, field pennycress,Galiumspp., common chickweed, and common hempnettle. Information from grower questionnaires indicates patterns of herbicide usage are related to location, changing with cropping system. Two herbicide modes of action most prone to select resistance, groups 1 and 2, continue to be widely and repeatedly used. There is little evidence that growers are aware of the level of resistance within their fields, but a majority have adopted herbicide rotations to proactively or reactively manage HR weeds.

Floristic composition and relative abundance of weeds in annual crops of Manitoba

1991 ◽  
Vol 71 (3) ◽  
pp. 831-839 ◽  
Author(s):  
A. G. Thomas
Keyword(s):  
Relative Abundance ◽  
Chenopodium Album ◽  
Floristic Composition ◽  
Sampling Procedure ◽  
Amaranthus Retroflexus ◽  
Wild Buckwheat ◽  
Wild Oats ◽  
Wild Mustard ◽  
Green Foxtail ◽  
Lamb’S Quarters

Annual surveys for weeds of fields seeded to spring wheat, barley, oats, flax, and canola in Manitoba were conducted during 1978, 1979, and 1981. Fields were surveyed during July and early August each year using a stratified random sampling procedure. Data for the crops and years were combined for analysis. The frequency, the area infested, and the density of the infestation were determined for each species. These three measures of the abundance of the weed were combined into a single synthetic value called relative abundance. Nine of the 152 species recorded by the surveyors accounted for 77% of the total relative abundance. Ranked in order by relative abundance, these species were green foxtail (Setaria viridis (L.) Beauv.), wild oats (Avena fatua L.), wild buckwheat (Polygonum convolvulus L.), annual smartweed (Polygonum spp.), Canada thistle (Cirsium arvense (L.) Scop.), lamb's-quarters (Chenopodium album L.), wild mustard (Sinapis arvensis L.), perennial sow-thistle (Sonchus arvensis L.), and redroot pigweed (Amaranthus retroflexus L.). Green foxtail was the predominant weed with an abundance value three times larger than wild oats or wild buckwheat. The pattern of dominance found in Manitoba fields was similar to results from comparable surveys in Saskatchewan and North Dakota. Key words: Relative abundance, weed survey, weed density, green foxtail, wild oats, wild buckwheat

scholarly journals Evaluation of Herbicide-Resistance Status on Populations of Littleseed Canarygrass (Phalaris Minor Retz.) from Southern Greece and Suggestions for their Effective Control

2012 ◽  
Vol 52 (3) ◽  
pp. 308-313 ◽  
Author(s):  
Ilias Travlos
Keyword(s):  
Herbicide Resistance ◽  
Resistance Index ◽  
Acetolactate Synthase ◽  
Effective Control ◽  
Cross Resistance ◽  
Resistance Mutations ◽  
Resistance Level ◽  
Phalaris Minor ◽  
Wide Range ◽  
Southern Greece

Evaluation of Herbicide-Resistance Status on Populations of Littleseed Canarygrass (Phalaris MinorRetz.) from Southern Greece and Suggestions for their Effective ControlIn 2010, a survey was conducted in the wheat fields of a typical cereal-producing region of Greece to establish the frequency and distribution of herbicide-resistant littleseed canarygrass (Phalaris minorRetz.). In total, 73 canarygrass accessions were collected and screened in a field experiment with several herbicides commonly used to control this weed. Most of the weed populations were classed as resistant (or developing resistance) to the acetyl-CoA varboxylase (ACCase)-inhibiting herbicide diclofop, while resistance to clodinafop was markedly lower. The results of the pot experiments showed that some of the canary populations were found to have a very high level of diclofop resistance (resistance index up to 12.4), while cross resistance with other herbicides was also common. The levels of resistance and cross resistance patterns among populations varied along with the different amounts and times of selection pressure. Such variation indicated either more than one mechanism of resistance or different resistance mutations in these weed populations. The population which had the highest diclofop resistance level, showed resistance to all aryloxyphenoxypropinate (APP) herbicides applied and non-ACCase inhibitors. Alternative ACCase-inhibiting herbicides, such as pinoxaden remain effective on the majority of the tested canarygrass populations, while the acetolactate synthase (ALS)-inhibiting herbicide mesosulfuron + iodosulfuron could also provide some solutions. Consequently, there is an opportunity to effectively control canarygrass by selecting from a wide range of herbicides. It is the integration of agronomic practices with herbicide application, which helps in effective management ofP. minorand particularly its resistant populations.

A survey of the occurrence of seedling weeds in spring annual crops in Manitoba

1991 ◽  
Vol 71 (3) ◽  
pp. 811-820 ◽  
Author(s):  
A. G. Thomas ◽  
D. I. Donaghy
Keyword(s):  
Chenopodium Album ◽  
Abundant Species ◽  
Amaranthus Retroflexus ◽  
Canada Thistle ◽  
Perennial Weed ◽  
Wild Buckwheat ◽  
Annual Crops ◽  
Wild Oats ◽  
Wild Mustard ◽  
Green Foxtail

A floristic survey for weeds in spring annual crops throughout Manitoba from 1975 to 1978 indicated the occurrence of a total of 83 species in 654 fields. Field counts were done during June when the crop and weeds were in the seedling stage. In terms of total abundance, the 28 annual dicotyledonous weeds were found to be the most important group among the 50 species occurring in more than 1% of the fields. Wild buckwheat (Polygonum convolvulus L.), wild mustard (Sinapis arvensis L.), redroot pigweed (Amaranthus retroflexus L.), and lamb's-quarters (Chenopodium album L.) were the most widespread and abundant species in this group with mean densities from 9.6 to 16.2 plants m−2. The combined abundance of green foxtail (Setaria viridis L.), wild oats (Avena fatua L.), and barnyard grass (Echinochloa crusgalli (L.) Beauv.), the three major annual monocotyledonous weeds, was nearly equal to that of the annual dicotyledonous weed group. Green foxtail was the most abundant weed, occurring in 89% of the fields at mean densities of 270.5 plants m−2. Canada thistle (Cirsium arvense (L.) Scop.) and perennial sow-thistle (Sonchus arvensis L.) were the most abundant species in the biennial and perennial weed group and had mean densities of 4.4–4.8 plants m−2 in infested fields. Key words: Weed survey, green foxtail, wild oats, wild buckwheat, wild mustard, Canada thistle

Comparison of Antihypertensives after Coronary Artery Surgery

2005 ◽  
Vol 13 (4) ◽  
pp. 302-306 ◽  
Author(s):  
Fevzi Toraman ◽  
Hasan Karabulut ◽  
Onur Goksel ◽  
Serdar Evrenkaya ◽  
Sumer Tarcan ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Sodium Nitroprusside ◽  
Artery Bypass ◽  
Effective Control ◽  
Hemodynamic Effects ◽  
Double Product ◽  
Myocardial Infraction ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Hypertension following coronary artery bypass grafting is a common problem that may result in postoperative myocardial infraction or bleeding, Hemodynamic effects were compared in 45 hypertensive coronary bypass patients randomized to receive either diltiazem, nitroglycerin, or sodium nitroprusside. Diltiazem was administered as an intravenous bolus of 0.3 mg·kg−1 within 5 min, followed by infusion of 0.1–0.8 mg·kg−1·h−1 in group 1. Nitroglycerin was infused at a rate of 1–3 μg·kg·h−1 in group 2, and sodium nitroprusside was given at a rate of 1–3 μg·kg−1·min−1 in group 3. Hemodynamic measurements were carried out before infusion (T1) and at 30 min (T2), 2 h (T3), and 12 h (T4) after initiation of treatment in the intensive care unit. Mean arterial pressure decreased significantly in all groups. There were no differences among groups at T1 and T2. At T3, heart rate in group 2 was significantly higher than group 1. At T3 and T4, the double product was highest in group 3 (group 1 vs. 3, p < 0.001). These results suggest that the hemodynamic effects of the 3 drugs are similar within the first 30 min. However, after 30 min, diltiazem affords better myocardial performance and more effective control of hypertension.

scholarly journals The occurrence of herbicide-resistant Avena fatua (wild oats) populations to ACCase-inhibiting herbicides in Ireland

2021 ◽  
Author(s):  
R. Byrne ◽  
A.V. Vijaya Bhaskar ◽  
J. Spink ◽  
R. Freckleton ◽  
P. Neve ◽  
...  
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Resistance Mechanism ◽  
Point Mutations ◽  
Acetolactate Synthase ◽  
Avena Fatua ◽  
Integrated Weed Management ◽  
Cross Resistance ◽  
Wild Oats ◽  
Als Inhibitor

Following growers’ reports of herbicide control problems, populations of 30 wild oats, Avena fatua, were collected from the south-east main arable counties of Ireland in 2016 and investigated for the occurrence and potential for herbicide resistance to acetyl-CoA carboxylase (ACCase) inhibitors pinoxaden, propaquizafop and cycloxydim, as well as acetolactate synthase (ALS) inhibitor mesosulfuron + iodosulfuron. Plant survival ≥20% was considered as the discriminating threshold between resistant and susceptible populations, when plants were treated with full recommended field rates of ACCase/ALS inhibitors. Glasshouse sensitivity screens revealed 2 out of 30 populations were cross-resistant to all three ACCase inhibitors. While three populations were cross-resistant to both pinoxaden and propaquizafop, and additionally, two populations were resistant to propaquizafop only. Different degree of resistance and cross-resistance between resistant populations suggest the involvement of either different point mutations or more than one resistance mechanism. Nevertheless, all populations including the seven ACCase-resistant populations were equally susceptible to ALS inhibitor. An integrated weed management (cultural/non-chemical control tactics and judicious use of herbicides) approach is strongly recommended to minimize the risk of herbicide resistance evolution.

Dintroaniline Herbicide Resistance in Rigid Ryegrass (Lolium rigidum)

Weed Science ◽  
1995 ◽  
Vol 43 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Fiona M. McAlister ◽  
Joseph A. M. Holtum ◽  
Stephen B. Powles
Keyword(s):  
Herbicide Resistance ◽  
Plant Material ◽  
Root Tissue ◽  
Cross Resistance ◽  
Lolium Rigidum ◽  
Green Foxtail ◽  
Low Levels ◽  
Rigid Ryegrass ◽  
Dinitroaniline Herbicides

Thirteen biotypes of rigid ryegrass were screened for trifluralin resistance. From these, the two most resistant biotypes, SLR 31 and SLR 10, were chosen for further studies involving exposure to other dinitroanilines, mitosis-inhibiting herbicides and14C-trifluralin. SLR 31, and SLR 10 exhibited an approximate 10-fold reduced sensitivity to trifluralin in comparison to susceptible biotypes. Resistance to five other dinitroaniline herbicides was observed, with reduced sensitivity varying from 32-fold for ethalfluralin to 2.5-fold for isopropalin. The resistance in rigid ryegrass to other herbicides and drugs that affect mitosis were tested. Resistance comparable to that of trifluralin was recorded for the herbicides terbutol and DCPA, while low levels of cross-resistance to amiprophosmethyl was present. Trifluralin affected mitotic indices at a much lower level in the susceptible biotypes than in the resistant biotypes. No differences in the uptake and translocation of14C-trifluralin were observed between resistant and susceptible biotypes. Most of the14C detected in the plant material was in the root tissue. A small level of14C was detected in the seeds, and no substantial increases were noted in coleoptile tissue. The resistance spectra in SLR 31 and SLR 10 were phenotypically similar to those occurring in an intermediate trifluralin-resistant goosegrass and trifluralin-resistant green foxtail.

ACCase-Inhibitor Herbicide Resistance in Downy Brome (Bromus tectorum) in Oregon

Weed Science ◽  
2007 ◽  
Vol 55 (2) ◽  
pp. 91-94 ◽  
Author(s):  
Daniel A. Ball ◽  
Sandra M. Frost ◽  
Larry H. Bennett
Keyword(s):  
Seed Production ◽  
Herbicide Resistance ◽  
Bromus Tectorum ◽  
Cross Resistance ◽  
Acetyl Coa Carboxylase ◽  
Downy Brome ◽  
Plant Mortality ◽  
Red Fescue ◽  
Application Rates ◽  
Group 1

In spring 2005, a downy brome population with possible resistance to fluazifop-P, an acetyl-CoA carboxylase (ACCase) inhibitor (group 1) herbicide was found in a commercial creeping red fescue seed production field, near La Grande, OR, where fluazifop-P had been used to control downy brome repeatedly over 7 yr. Greenhouse experiments were conducted to confirm resistance to a number of group 1 herbicides. The suspected resistant downy brome accession was tested for resistance to fluazifop-P and tested for cross-resistance to other aryloxyphenoxy propionate (APP) and cyclohexanedione (CHD) herbicides, including quizalofop-P, sethoxydim, and clethodim. Data recorded included plant-mortality counts and biomass. Tests revealed that the La Grande downy brome accession was highly resistant to fluazifop-P and sethoxydim at all tested rates. The La Grande accession suffered no mortality from fluazifop-P or sethoxydim treatments up to the maximum tested rate of eight times (8×) the labeled recommendation. The La Grande accession was resistant to quizalofop-P and clethodim at the labeled rate or less but was susceptible to application rates higher than the labeled rate. The control downy brome accession was completely susceptible to fluazifop-P, quizalofop-P, and clethodim at all rates and exhibited increasing susceptibility with increasing sethoxydim rate. This pattern of cross-resistance differs from that of a previously reported case of ACCase resistance in downy brome.

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