Distribution and frequency of herbicide-resistant wild oat (Avena spp.) across the Western Australian grain belt

2009 ◽  
Vol 60 (1) ◽  
pp. 25 ◽  
Author(s):  
Mechelle J. Owen ◽  
Stephen B. Powles
Keyword(s):  
Herbicide Resistance ◽  
Wild Oat ◽  
Cultural Management ◽  
Herbicide Resistant ◽  
Low Level ◽  
Resistance Evolution ◽  
Modes Of Action ◽  
Random Survey ◽  
Herbicide Use ◽  
Western Australian

In 2005, a random survey was conducted across 14 million hectares of the Western Australian grain belt to establish the frequency and distribution of herbicide-resistant wild oat (Avena spp.) in cropping fields. In total, 677 cropping fields were visited, with wild oat populations collected from 150 fields. These wild oat populations were screened with several herbicides commonly used to control this weed. Most of the wild oat populations (71%) were found to contain individuals resistant to the ACCase-inhibiting herbicide diclofop-methyl. Resistance to other ACCase-inhibiting herbicides was markedly lower. Herbicides of alternative modes of action were effective on all wild oat populations. Overall, wild oat resistance to diclofop-methyl was found to be widespread across the Western Australian grain belt, but resistance to other herbicides was relatively low. Therefore, through diversity in herbicide use and with cultural management, it is possible to maintain wild oat populations at a low level and/or minimise herbicide resistance evolution.

Widespread occurrence of multiple herbicide resistance in Western Australian annual ryegrass (Lolium rigidum) populations

2007 ◽  
Vol 58 (7) ◽  
pp. 711 ◽  
Author(s):  
Mechelle J. Owen ◽  
Michael J. Walsh ◽  
Rick S. Llewellyn ◽  
Stephen B. Powles
Keyword(s):  
Herbicide Resistance ◽  
Cropping Systems ◽  
Distribution Patterns ◽  
Herbicide Resistant ◽  
Crop Fields ◽  
Crop Field ◽  
Sustainability Challenges ◽  
Random Survey ◽  
Als Inhibitor ◽  
Western Australian

In 2003, a random survey was conducted across the Western Australian wheatbelt to establish the frequency and distribution of herbicide resistance in ryegrass populations infesting crop fields. Five hundred cropping fields were visited at crop maturity, and ryegrass seed was collected in 452 of these fields. Subsequently, each crop field population was screened with herbicides of various modes of action that are commonly used for ryegrass control in Australian cropping systems. Most of these ryegrass populations were found to be resistant to the ACCase-inhibitor herbicide diclofop-methyl (68%) and the ALS-inhibitor herbicide sulfometuron (88%). A comparison of resistance levels in the same agronomic zones surveyed 5 years earlier determined that there had been an increase of 20 percentage points in the frequency of resistance over this 5-year period. This survey also determined that the majority (64%) of populations were found to be multiple resistant to both diclofop-methyl and sulfometuron. The distribution patterns of the collected populations indicated that there were higher frequencies of resistant and developing resistance populations occurring in the intensively cropped regions of the wheatbelt, which had greater herbicide selection pressure. Of concern is that 24% and 8% of populations were found to be developing resistance to trifluralin and clethodim, respectively. Currently these herbicides are heavily relied upon for control of ACCase and ALS herbicide resistant ryegrass. Nearly all populations remain susceptible to glyphosate. Ryegrass across the WA wheatbelt now exhibits multiple resistance across many but not all herbicides, posing severe management and sustainability challenges.

ACCase-Inhibiting Herbicide-ResistantAvenaspp. Populations from the Western Australian Grain Belt

2012 ◽  
Vol 26 (1) ◽  
pp. 130-136 ◽  
Author(s):  
M. S. Ahmad-Hamdani ◽  
Mechelle J. Owen ◽  
Qin Yu ◽  
Stephen B. Powles
Keyword(s):  
Herbicide Resistance ◽  
Dose Response ◽  
Resistance Index ◽  
Wild Oat ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Grain Crops ◽  
High Level ◽  
Western Australian

Avenaspp. are world weeds with many cases of evolved herbicide resistance. In Australia,Avenaspp. (wild oat and sterile oat) are a major problem, especially in grain crops. Acetyl-CoA carboxylase (ACCase)–inhibiting herbicides have been used extensively since the late 1970s forAvenaspp. control. However, continued reliance on these herbicides has resulted in the evolution of resistantAvenaspp. populations. Resistance across many ACCase-inhibiting herbicides was characterized in fourAvenaspp. populations from the Western Australian grain belt. Dose–response experiments were conducted to determine the level of resistance to the aryloxyphenoxypropionates and cyclohexanediones and to the phenylpyrazoline herbicide pinoxaden. On the basis of resistance index values, all four resistant populations exhibited high-level diclofop resistance but varied in the level of resistance to other ACCase-inhibiting herbicides tested. It is evident thatAvenaspp. populations from the Western Australian grain belt have evolved resistance to a number of ACCase-inhibiting herbicides.

Field and producer survey of ACCase resistant wild oat in Manitoba

1997 ◽  
Vol 77 (4) ◽  
pp. 709-715 ◽  
Author(s):  
Luc Bourgeois ◽  
Ian N. Morrison ◽  
David Kelner
Keyword(s):  
High Risk ◽  
Herbicide Resistance ◽  
Wild Oat ◽  
Medium Risk ◽  
Risk Areas ◽  
Resistance Assessment ◽  
Herbicide Use ◽  
Risk Categories ◽  
Weed Survey ◽  
Group 1

In a previous study, 729 townships in Manitoba were differentiated as being at low, medium, or high risk of evolving wild oat resistant to Group 1 herbicides based on herbicide use histories from 1981 to 1993. In the present study, 16 townships representing the three risk categories were surveyed in 1994 in order to determine the percentage of resistant wild oat patches. As well, a questionnaire was mailed to farmers in these townships requesting information on practices and attitudes relating to herbicide resistance. The wild oat survey consisted of sampling seed from conspicuous wild oat patches visible from north-south roads in each township. A total of 533 samples were collected and screened with fenoxaprop-P and sethoxydim using a bioassay. An average of eight resistant wild oat patches was found in the high risk townships. This was significantly higher than in low and medium risk townships where an average of less than one resistant wild oat patch per township was detected. The attitude of producers towards herbicide resistance was similar in all risk categories. However, the number of respondents suspecting Group 1 resistance on their farms was related to risk categories with producers in high risk areas suspecting the most cases of resistance. Key words: Weed survey, resistance assessment, wild oat, ACCase inhibitors

Exploring the Potential for a Regulatory Change to Encourage Diversity in Herbicide Use

Weed Science ◽  
2016 ◽  
Vol 64 (SP1) ◽  
pp. 649-654 ◽  
Author(s):  
Stephen B. Powles ◽  
Todd A. Gaines
Keyword(s):  
Weed Control ◽  
Environmental Protection Agency ◽  
Financial Incentives ◽  
Resistance Management ◽  
The United States ◽  
Regulatory Change ◽  
Herbicide Resistant ◽  
Resistance Evolution ◽  
Application Frequency ◽  
Herbicide Use

An overreliance on herbicides in several important grain- and cotton-producing regions of the world has led to the widespread evolution of herbicide-resistant weed populations. Of particular concern are weed populations that exhibit simultaneous resistance to multiple herbicides (MHR). Too often, herbicides are the only tool used for weed control. We use the term herbicide-only syndrome (HOS) for this quasi-addiction to herbicides. Growers and their advisers focus on herbicide technology, unaware of or ignoring basic evolutionary principles or the necessary diversity provided by other methods of weed control. Diversity in weed control practices disrupts resistance evolution. Significant challenges exist to implementing diversity, including how to address information so that producers choose to alter existing behaviors (HOS) and take calculated risks by attempting new and more complex strategies. Herbicide resistance management in the long term will require creativity in many sectors, including roles for growers, industry, researchers, consultants, retailers, and regulators. There can be creativity in herbicide registration and regulation, as exemplified by the recent U.S. Environmental Protection Agency program that encourages herbicide registrants to register products in minor crops. We propose one idea for a regulatory incentive to enable herbicide registrants in jurisdictions such as the United States to receive an extended data exclusivity period in exchange for not developing one new herbicide in multiple crops used together in rotation, or for implementing stewardship practices such as robust mixtures or limitations on application frequency. This incentive would provide a mechanism to register herbicides in ways that help to ensure herbicide longevity. Approaches based only on market or financial incentives have contributed to the current situation of widespread MHR. Our suggestion for regulatory creativity is one way to provide both financial and biological benefits to the registering company and to the overall stakeholder community by incentivizing good resistance management.

Multiple-herbicide resistance across four modes of action in wild radish (Raphanus raphanistrum)

Weed Science ◽  
2004 ◽  
Vol 52 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Michael J. Walsh ◽  
Stephen B. Powles ◽  
Brett R. Beard ◽  
Ben T. Parkin ◽  
Sally A. Porter
Keyword(s):  
Herbicide Resistance ◽  
Crop Production ◽  
Acetolactate Synthase ◽  
Wild Radish ◽  
Raphanus Raphanistrum ◽  
Production Program ◽  
Use Patterns ◽  
Modes Of Action ◽  
Herbicide Use ◽  
Multiple Herbicide Resistance

Populations of wild radish were collected from two fields in the northern Western Australian wheatbelt, where typical herbicide-use patterns had been practiced for the previous 17 seasons within an intensive crop production program. The herbicide resistance status of these populations clearly established that there was multiple-herbicide resistance across many herbicides from at least four modes of action. One population exhibited multiple-herbicide resistance to the phytoene desaturase (PDS)–inhibiting herbicide diflufenican (3.0-fold), the auxin analog herbicide 2,4-D (2.2-fold), and the photosystem II–inhibiting herbicides metribuzin and atrazine. Another population was found to be multiply resistant to the acetolactate synthase–inhibiting herbicides, the PDS-inhibiting herbicide diflufenican (2.5-fold), and the auxin analog herbicide 2,4-D amine (2.4-fold). Therefore, each population has developed multiple-herbicide resistance across several modes of action. The multiple resistance status of these wild radish populations developed from conventional herbicide usage in intensive cropping rotations, indicating a dramatic challenge for the future control of wild radish.

Inheritance of multiple herbicide resistance in wild oat (Avena fatua L.)

2006 ◽  
Vol 86 (1) ◽  
pp. 317-329 ◽  
Author(s):  
Jocelyn D Karlowsky ◽  
Anita L Brûlé-Babel ◽  
Lyle F Friesen ◽  
Rene C Van Acker ◽  
Gary H Crow
Keyword(s):  
Herbicide Resistance ◽  
Nuclear Gene ◽  
Avena Fatua ◽  
Multiple Resistance ◽  
Western Canada ◽  
Wild Oat ◽  
Herbicide Resistant ◽  
Insight Into ◽  
Resistance Genetics ◽  
Multiple Herbicide Resistance

To gain some insight into the surprisingly frequent occurrence of multiple herbicide resistant wild oat in western Canada, the inheritance of multiple herbicide resistance was studied in two wild oat (Avena fatua L.) populations, UMWO12-01 and UMWO12-03, from Manitoba, Canada. Both populations are resistant to each of three distinct herbicides, imazametha benz-methyl, flamprop-methyl, and fenoxaprop-p-ethyl (hereafter referred to as imazamethabenz, flamprop, and fenoxaprop-P, respectively). Crosses were made between each resistant (R) population and a susceptible (S) wild oat population (UM5) (R/S crosses), and between the two resistant populations (R/R crosses). Subsets of parental, F2 plants, and F2-derived F3 (F2:3) families were treated separately with each of the three herbicides and classified as R or S for individual plants, and homozygous R, segregating, or homozygous S for F2:3 families. F2 plants and F2:3 families from R/S crosses segregated in 3R:1S and 1 homozygous R:2 segregating:1 homozygous S ratios, respectively. These ratios indicate that a single dominant or semi-dominant nuclear gene controls resistance to each of these herbicides in each population. F2 plants and F2:3 families from R/R crosses segregated for resistance/susceptibility when treated with either imazamethabenz or flamprop. Therefore, the genes for resistance to these two herbicides are different in each R population. Individual F2:3 family response demonstrated that the genes were not independent of each other, indicating possible linkage between the genes for resistance to each herbicide. Genetic linkage could explain how the wild oat populations developed multiple resistance in the absence of selection by two of the herbicides, imazamethabenz and flamprop. Key words: Wild oat, Avena fatua, herbicide resistance, genetics of resistance, multiple resistance

The frequency of herbicide-resistant wild oat (Avena spp.) populations remains stable in Western Australian cropping fields

2016 ◽  
Vol 67 (5) ◽  
pp. 520 ◽  
Author(s):  
Mechelle J. Owen ◽  
Stephen B. Powles
Keyword(s):  
Weed Management ◽  
Cropping Systems ◽  
Good Control ◽  
Acetolactate Synthase ◽  
Management Options ◽  
Herbicide Resistant ◽  
Wide Range ◽  
Random Survey ◽  
First Time ◽  
Western Australian

Avena is a problematic weed of cropping regions of southern Australia and many areas of the world. In 2010, a random survey was conducted across 14 million hectares of the Western Australian grain belt to monitor the change in herbicide resistance levels by comparing resistance frequency results with a survey conducted in 2005. Screening Avena populations with herbicides commonly used to control this weed revealed that 48% of Avena populations displayed resistance to the commonly used acetyl-Co A carboxylase-inhibiting herbicides, which was lower than that found in 2005 (71%). The broad-spectrum herbicides glyphosate and paraquat provided good control of all Avena populations. Resistance to acetolactate synthase-inhibiting herbicides and to flamprop were detected for the first time in Western Australia in this survey. Therefore, a wide range of weed management options that target all phases of the cropping program are needed to sustain these cropping systems in the future.

Multiple herbicide-resistant wild radish (Raphanus raphanistrum) populations dominate Western Australian cropping fields

2015 ◽  
Vol 66 (10) ◽  
pp. 1079 ◽  
Author(s):  
Mechelle J. Owen ◽  
Neree J. Martinez ◽  
Stephen B. Powles
Keyword(s):  
Weed Management ◽  
Cropping Systems ◽  
Acetolactate Synthase ◽  
Raphanus Raphanistrum ◽  
Management Options ◽  
Herbicide Resistant ◽  
Wide Range ◽  
Random Survey ◽  
Imidazolinone Herbicides ◽  
Western Australian

Raphanus raphanistrum is a problematic weed, which has become increasingly difficult to control in Australian cropping regions. In 2010, a random survey was conducted across 14 million ha of the Western Australian grain belt to establish the frequency of herbicide resistance in R. raphanistrum and to monitor the change in resistance levels by comparing results with a previous survey in 2003. Screening R. raphanistrum populations with herbicides commonly used to control this weed revealed that most populations (84%) contained individual plants resistant to the acetolactate synthase-inhibiting herbicide chlorsulfuron, whereas 49% of populations also had plants resistant to the imidazolinone herbicides. Resistance to other mode of action herbicides (2,4-D (76%) and diflufenican (49%)) was also common. Glyphosate, atrazine and pyrasulfotole + bromoxynil remained effective on most R. raphanistrum populations. These results demonstrate that resistance to some herbicides has increased significantly since 2003 when the values were 54% for chlorsulfuron and 60% for 2,4-D; therefore, a wide range of weed management options that target all phases of the cropping program are needed to sustain these cropping systems in the future.

A decade of monitoring herbicide resistance in Lolium rigidum in Australia

2006 ◽  
Vol 46 (9) ◽  
pp. 1151 ◽  
Author(s):  
J. C. Broster ◽  
J. E. Pratley
Keyword(s):  
Herbicide Resistance ◽  
Cultural Practices ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Herbicide Resistant ◽  
South Wales ◽  
Australian State ◽  
Group B ◽  
Random Survey ◽  
Group D

Charles Sturt University commenced herbicide resistance monitoring in 1991. A random survey in 1991 to determine the level of resistance in annual ryegrass (Lolium rigidum) to selective herbicides across the south-west slopes region of New South Wales found that 30% of samples were resistant to at least 1 herbicide. A subsequent survey of commercially available ryegrass seed found that 58% of these samples were resistant to at least 1 herbicide. As a result of these findings, a commercial testing service was established and has since received samples from a large proportion of the southern Australian cropping belt. Seventy-seven percent of samples tested were resistant to Group AI, 40% to Group B and 22% to Group AII herbicides. Lower levels of resistance were found to Group D (8%), Group C (1%) and Group M (0.4%) herbicides. The correlation between resistance in Group AI and AII herbicides was lower than expected given that these herbicides are considered to have the same mode of action. Within the Group AI herbicides the observed response of the samples was consistent across herbicide formulations. Resistance to clethodim varied from observed responses to other Group AII herbicides. The variation in resistance levels (and degree of multiple resistance) in each Australian state is discussed in relation to environmental conditions and cultural practices. The size of this dataset allows for the analysis of the relationships present among herbicide resistant annual ryegrass.

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