A quarter of a century of monitoring herbicide resistance in Lolium rigidum in Australia

2019 ◽  
Vol 70 (3) ◽  
pp. 283 ◽  
Author(s):  
J. C. Broster ◽  
J. E. Pratley ◽  
R. H. L. Ip ◽  
L. Ang ◽  
K. P. Seng
Keyword(s):  
Herbicide Resistance ◽  
Acetolactate Synthase ◽  
Resistance Testing ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Epsp Synthase ◽  
Testing Service ◽  
South Wales ◽  
Significant Incidence ◽  
Random Survey

Charles Sturt University has operated a commercial herbicide resistance testing service since 1991, following a random survey of the South West Slopes region of New South Wales that identified significant incidence of herbicide resistance in annual ryegrass (Lolium rigidum Gaud.). Other surveys of cropping regions of southern Australia conducted at that time also found a significant incidence of resistance. In the subsequent 25-year period, the testing service has received samples from the majority of the southern Australian cropping belt. Overall, 80% of samples tested were resistant to acetyl-CoA carboxylase (ACCase) inhibiting aryloxyphenoxypropionate and phenylpyrazole herbicides, 56% to acetolactate synthase (ALS) inhibiting herbicides, and 24% to ACCase-inhibiting cyclohexanedione herbicides. The incidences of resistance to inhibitors of photosynthesis at PSII, tubulin-formation inhibitors, and 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase inhibiting herbicides have remained <10% of samples tested. The relationships between many herbicide groups and subgroups are discussed, as is the variability in resistance incidence and the forms of cross or multiple resistance for each state. This paper builds on an earlier publication of 14 years of testing history. At >5000 samples, the size and geographical spread of this dataset allows for valuable analyses of the relationships present in herbicide-resistant populations of annual ryegrass.

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.

Development of herbicide resistance in annual ryegrass populations (Lolium rigidum Gaud.) in the cropping belt of Western Australia

1995 ◽  
Vol 35 (1) ◽  
pp. 67 ◽  
Author(s):  
GS Gill
Keyword(s):  
Herbicide Resistance ◽  
Western Australia ◽  
Acetolactate Synthase ◽  
Strong Relationship ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Development Of Resistance ◽  
High Level ◽  
Als Inhibitor ◽  
The Relationship

Annual ryegrass (Lolium rigidum) samples from the cropping belt of Western Australia were screened for herbicide resistance in 1992 and 1993. There was a strong relationship between the number of applications of a herbicide group and development of resistance in ryegrass populations. Resistance was detected in all populations that received >7 applications of aryloxyphenoxypropionate (AOPP) and cyclohexanedione (CHD) herbicides or >4 applications of sulfonylurea (SU) herbicides. Some AOPP-resistant populations had also developed crossresistance to SU herbicides, a group with a different mode of action. Inclusion of pasture in the rotation had little effect on the relationship between the number of applications of the AOPP and SU herbicides and development of resistance. A subset of 33 populations was chosen to determine the response of triasulfuron-resistant populations to sulfometuron, a nonselective SU herbicide which has been shown to be effective against metabolic-type resistance. All triasulfuron-resistant populations were found to be resistant to sulfometuron, possibly due to insensitive acetolactate synthase (ALS) in these ryegrass populations. Some of these SU-resistant populations were also resistant to the imidazolinone herbicide imazethapyr, another ALS inhibitor. However, there were several populations with a high level of SU resistance that were still susceptible to imazethapyr.

scholarly journals Cropping practices influence incidence of herbicide resistance in annual ryegrass (Lolium rigidum) in Australia

2019 ◽  
Vol 70 (1) ◽  
pp. 77 ◽  
Author(s):  
J. C. Broster ◽  
J. E. Pratley ◽  
R. H. L. Ip ◽  
L. Ang ◽  
K. P. Seng
Keyword(s):  
Herbicide Resistance ◽  
Acetolactate Synthase ◽  
Farming System ◽  
Control Measures ◽  
Annual Ryegrass ◽  
Farming Practices ◽  
Lolium Rigidum ◽  
Weed Species ◽  
Resistance Evolution ◽  
Australian Bureau Of Statistics

Herbicide resistance is a common occurrence in southern Australia. The evolution of herbicide resistance is influenced by the selection pressure placed on the weed species controlled by that herbicide. Results from resistance screening of ~4500 annual ryegrass (Lolium rigidum Gaud.) samples were entered in a GIS database, together with several agricultural parameters used in the Australian Bureau of Statistics Agricultural Surveys. This allowed a study of the associations between mode of action of resistance, geographic distribution of resistance across southern Australia, and farming practices employed in particular regions. Cultivation was negatively associated with resistances in acetyl-CoA carboxylase (ACCase)-inhibiting cyclohexanedione and acetolactate synthase (ALS)-inhibiting herbicides. Higher proportions of wheat sown were associated with higher incidences of resistance. ACCase-inhibiting aryloxyphenoxypropionate and cyclohexanedione and ALS-inhibiting resistances were higher in those shires where soils were predominantly acidic. This study demonstrates the association between farm practice and the evolution of herbicide resistance. The analysis provides reinforcement to the principle of rotating chemical modes of action with non-chemical weed control measures to minimise the risk of herbicide resistance evolution in any farming system.

Incidence of Herbicide Resistance in Rigid Ryegrass (Lolium rigidum) across Southeastern Australia

2012 ◽  
Vol 26 (3) ◽  
pp. 391-398 ◽  
Author(s):  
Peter Boutsalis ◽  
Gurjeet S. Gill ◽  
Christopher Preston
Keyword(s):  
Herbicide Resistance ◽  
South Australia ◽  
Acetolactate Synthase ◽  
Lolium Rigidum ◽  
Acetyl Coenzyme A ◽  
Main Method ◽  
Herbicide Resistant ◽  
Southeastern Australia ◽  
High Incidence ◽  
Rigid Ryegrass

Herbicide resistance in rigid ryegrass is an escalating problem in grain-cropping fields of southeastern Australia due to increased reliance on herbicides as the main method for weed control. Weed surveys were conducted between 1998 and 2009 to identify the extent of herbicide-resistant rigid ryegrass across this region to dinitroaniline, and acetolactate synthase- and acetyl coenzyme A (CoA) carboxylase-inhibiting herbicides. Rigid ryegrass was collected from cropped fields chosen at random. Outdoor pot studies were conducted during the normal winter growing season for rigid ryegrass with PRE-applied trifluralin and POST-applied diclofop-methyl, chlorsulfuron, tralkoxydim, pinoxaden, and clethodim. Herbicide resistance to trifluralin in rigid ryegrass was identified in one-third of the fields surveyed from South Australia, whereas less than 5% of fields in Victoria exhibited resistance. In contrast, resistance to chlorsulfuron was detected in at least half of the cropped fields across southeastern Australia. Resistance to the cereal-selective aryloxyphenoxypropionate-inhibiting herbicides diclofop-methyl, tralkoxydim, and pinoxaden ranged between 30 and 60% in most regions, whereas in marginal cropping areas less than 12% of fields exhibited resistance. Resistance to clethodim varied between 0 and 61%. Higher levels of resistance to clethodim were identified in the more intensively cropped, higher-rainfall districts where pulse and canola crops are common. These weed surveys demonstrated that a high incidence of resistance to most tested herbicides was present in rigid ryegrass from cropped fields in southeastern Australia, which presents a major challenge for crop producers.

scholarly journals Rapid On-Farm Testing of Resistance in Lolium rigidum to Key Pre- and Post-Emergence Herbicides

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1879
Author(s):  
Martina Badano Perez ◽  
Hugh J. Beckie ◽  
Gregory R. Cawthray ◽  
Danica E. Goggin ◽  
Roberto Busi
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Rapid Detection ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Herbicide Resistant ◽  
Primary Dormancy ◽  
Wide Range ◽  
Control Options ◽  
On Farm

Overreliance on herbicides for weed control is conducive to the evolution of herbicide resistance. Lolium rigidum (annual ryegrass) is a species that is prone to evolve resistance to a wide range of herbicide modes of action. Rapid detection of herbicide-resistant weed populations in the field can aid farmers to optimize the use of effective herbicides for their control. The feasibility and utility of a rapid 7-d agar-based assay to reliably detect L. rigidum resistant to key pre- and post-emergence herbicides including clethodim, glyphosate, pyroxasulfone and trifluralin were investigated in three phases: correlation with traditional pot-based dose-response assays, effect of seed dormancy, and stability of herbicides in agar. Easy-to-interpret results were obtained using non-dormant seeds from susceptible and resistant populations, and resistance was detected similarly as pot-based assays. However, the test is not suitable for trifluralin because of instability in agar as measured over a 10-d period, as well as freshly-harvested seeds due to primary dormancy. This study demonstrates the utility of a portable and rapid assay that allows for on-farm testing of clethodim, glyphosate, and pyroxasulfone resistance in L. rigidum, thereby aiding the identification and implementation of effective herbicide control options.

scholarly journals Developing a Petri dish test to detect resistance to key herbicides in Lolium rigidum

2021 ◽  
Author(s):  
Martina Badano Perez ◽  
Hugh J Beckie ◽  
Gregory R Cawthray ◽  
Danica E Goggin ◽  
Roberto Busi
Keyword(s):  
Weed Management ◽  
Technology Use ◽  
Petri Dish ◽  
Resistance Testing ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Management Interventions ◽  
Wide Range ◽  
Whole Plants ◽  
On Farm

AbstractOverreliance on herbicides for weed control is conducive to the evolution of herbicide resistance. Annual ryegrass (Lolium rigidum Gaud.) is a species that is prone to evolve resistance to a wide range of herbicide modes of action. Rapid detection of herbicide-resistant weed populations in the field can aid farmers to optimize the use of herbicides for their control. The feasibility of a portable agar-based test to rapidly and reliably detect annual ryegrass resistance to key herbicides such as clethodim, glyphosate, pyroxasulfone and trifluralin on-farm was investigated. The three research phases of this study show that: a) easy-to-interpret results are obtained with non-dormant seed from well-characterised susceptible and resistant populations, and resistance is detected as effectively as with traditional dose-response pot-based resistance assays. However, the test may not be suitable for portable use on-farm because of b) the low stability of some herbicides such as trifluralin and clethodim in agar and c) the tendency of seed dormancy in freshly-harvested seeds to confound the results. The agar-based test is best used as a research tool as a complement to confirm results obtained in traditional pot-based resistance screenings. Comprehensive agar test and / or whole-plant resistance tests by herbicide application at the recommended label rate (whole plants grown in pots) are the current benchmark for proactive in- and off-season resistance testing and should be promoted more widely to allow early detection of resistance, optimization of herbicide technology use and deploy appropriate weed management interventions.

Relationship between herbicide resistance in Lolium rigidum and populations of Anguina funesta, the nematode vector in annual ryegrass toxicity

1994 ◽  
Vol 34 (5) ◽  
pp. 633 ◽  
Author(s):  
IT Riley ◽  
GS Gill
Keyword(s):  
Herbicide Resistance ◽  
Rapid Development ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Annual Ryegrass Toxicity ◽  
Causal Bacterium

Samples of annual ryegrass (Lolium rigidum Gaudin) seed tested for herbicide resistance were examined for seed-galls of Anguina funesta, the nematode vector of Clavihacter toxicus the causal bacterium in annual ryegrass toxicity (ARGT). Of the 246 samples examined, 63% contained galls, with concentrations up to 1400 galls per 10 g of seed. Higher herbicide resistance was associated with increased concentrations of A. funesta. We conclude that use of selective herbicides for ARGT control may have contributed to the rapid development of herbicide resistance.

Epichloë occultans infection in Australian Lolium rigidum is associated with cropping history and environment but not with herbicide resistance status of host plant

2018 ◽  
Vol 69 (6) ◽  
pp. 642
Author(s):  
Joseph R. Moore ◽  
James E. Pratley ◽  
Leslie A. Weston ◽  
Wade J. Mace ◽  
John C. Broster ◽  
...  
Keyword(s):  
Herbicide Resistance ◽  
Invasive Plant ◽  
Fungal Endophyte ◽  
Infection Frequency ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Selection Pressures ◽  
Environmental Selection ◽  
Millennium Drought ◽  
Endophyte Infection

Annual ryegrass (Lolium rigidum Gaud.) is a troublesome invasive plant in southern Australian cropping systems and is typically infected with a fungal endophyte, Epichloë occultans. Potential links between herbicide resistance and endophyte infection were investigated in this study. We surveyed 391 ryegrass populations from geographically distinct, naturalised pasture and cropping areas across southern Australia and compared frequencies of seed-borne endophyte infection in the collected seed samples from mature annual ryegrass. Data on herbicide resistance from similar seedlots were cross-referenced with endophyte infection frequency to examine the potential relationship between herbicide resistance and endophyte infection. Seeds from cropping paddocks exhibited a significantly higher frequency of endophyte infection than pasture paddocks sampled from the same region. Frequencies of endophyte infection in annual ryegrass declined across Australia during 2001–09, whereas the opposite trend was observed during 2009–12. Impacts of the Australian Millennium Drought, the correspondingly altered rainfall patterns and environmental selection pressures have a role in determining observed endophyte infection frequencies. However, there was no significant correlation between endophyte frequency and herbicide resistance in the populations evaluated. Differences in endophyte infection frequencies were associated with farming practices, and require further examination to determine causative selection pressures encountered in Australian field settings.

The influence of wheat density and spatial arrangement on annual ryegrass, Lolium rigidum Gaudin, competition

1985 ◽  
Vol 36 (3) ◽  
pp. 361 ◽  
Author(s):  
RW Medd ◽  
BA Auld ◽  
DR Kemp ◽  
RD Murison
Keyword(s):  
Field Experiments ◽  
Spatial Arrangement ◽  
Triticum Aestivum L ◽  
Yield Reduction ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Yield Model ◽  
Common Trend ◽  
South Wales ◽  
Crop Density

The influence of wheat (Triticum aestivum L.) planting arrangement and density on the competitive effect of the weed, annual ryegrass (Lolium rigidum Gaudin), was examined in field experiments over three climatically contrasting years on the central western slopes of New South Wales. Results for three experiments conformed to a common trend. Geometrical arrangement of the crop (rectangularities of 1 to 6.4) at any one of a range of crop densities had no significant effect (P > 0.05) on ryegrass competition, expressed as relative wheat grain yield reduction. However, the effect of ryegrass was substantially reduced by increasing wheat sowing density from 40 or 75 to 200 plants m-2. In analysing models of weed competition a reciprocal yield model (I/ Y = 0.0092 + 0.0037X, r2= 0.89) predicted yield reduction (Y, as per cent of weed-free controls), especially when used with the ratio of weed density to crop density (X), with residual sums of squares lower than for other models.

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