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.

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.

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.

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.

Influence of forage legume species, seeding rate and seed size on competitiveness with annual ryegrass (Lolium rigidum) seedlings

2006 ◽  
Vol 46 (5) ◽  
pp. 627 ◽  
Author(s):  
B. S. Dear ◽  
A. Hodge ◽  
D. Lemerle ◽  
J. E. Pratley ◽  
B. A. Orchard ◽  
...  
Keyword(s):  
Seed Size ◽  
Trifolium Subterraneum ◽  
Legume Species ◽  
Annual Ryegrass ◽  
Forage Legume ◽  
Lolium Rigidum ◽  
Seeding Rate ◽  
Forage Crops ◽  
Relative Growth Rates ◽  
Herbicide Resistant

Annual legumes sown as short-term forage crops are an important non-chemical option for the control of herbicide-resistant annual ryegrass (Lolium rigidum L.). The relative ability of 5 annual forage legume species (Trifolium subterraneum L., T. michelianum Savi., T. alexandrinum L., Medicago murex Wild and Vicia benghalensis L.) to suppress annual ryegrass seedlings was examined in a glasshouse study. The experiment investigated the importance of legume species, seed size and seeding rate in influencing the relative competitiveness of the legumes. Balansa clover (T. michelianum) and berseem clover (T. alexandrinum), the smallest seeded of the legume species, were the most effective of the 5 legume species, when compared at equivalent seeding rates, at reducing ryegrass biomass. Legume leaf area and biomass were the 2 factors measured that were most closely associated with depressing ryegrass biomass and were themselves most influenced by legume species and seeding rate. Balansa clover and vetch (V. benghalensis) were the most effective at restricting the amount of light penetrating to 50% of the height of the canopy over a range of seeding rates. The study showed that the competitiveness of forage break crops can be optimised by maximising legume biomass through selecting small-seeded legume species with high relative growth rates and dense canopies and by increasing the seeding rate where seed costs are low.

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.

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.

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