Crop Updates 2007 - Weeds

This session covers thirty two papers from different authors: 1. ACKNOWLEDGEMENTS, Alexandra Douglas CONVENOR – WEEDS DEPARTMENT OF AGRICULTURE AND FOOD WILD RADISH MANAGEMENT 2. Decimate a wild radish seed bank in five years, Peter Newman, Sally Peltzer, Abul Hashem and Aik Cheam, Department of Agriculture and Food 3. High level of seed-set control in wild radish is achievable, Aik Cheam and Siew Lee,Department of Agriculture and Food 4. Wild radish: Best management practice, Aik Cheam and Siew Lee, Department of Agriculture and Food 5. Control of phenoxy resistant wild radish through the combined effects of wheat competition and phenoxy herbicides, Natalie Maguire and Michael Walsh, WAHRI, School of Plant Biology, University of Western Australia 6.Efficacy of florasulam on chlorsulfuron resistant and susceptible wild radish populations in Western Australia, Michael Walsh1 and Dan Cornally2, 1WAHRI, School of Plant Biology, University of Western Australia, 2Dow Agrosciences Australia 7. Does liming to increase soil pH limit the growth and development of wild radish (Raphanus raphanistrum)Matt Willis and Michael Walsh, WAHRI, School of Plant Biology, University of Western Australia IWM TECHNIQUES AND SEEDBANKS 8. Weed trimming – a potential technique to reduce weed seed set, Glen Riethmuller, Abul Hashem and Shahab Pathan, Department of Agriculture and Food 9. Burn narrow windrows in the wind, Peter Newman1and Michael Walsh2, 1Department of Agriculture and Food, 2Research Fellow, WA Herbicide Resistance Initiative 10. Winning the Weed War with the Weed Seed Wizard! Michael Renton, Sally Peltzer and Art Diggle, Department of Agriculture and Food HERBICIDE RESISTANCE AND GENE FLOW 11. Frequency of herbicide resistance in wild oat (Avena fatua) across the Western Australian wheatbelt, Mechelle Owen and Stephen Powles, WA Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia 12. Pollen mediated gene flow of herbicide resistance can occur over long distances doe annual ryegrass (Lolium rigidum): Results of two years with different meteorological conditions, Roberto Busi, Robert Barrett-Lennard and Stephen B. Powles, Western Australian Herbicide Resistance Initiative, School of Plant Biology – University of Western Australia 13. Doublegee has developed resistance to metsulfuron-methyl within WA wheatbelt, Dr Abul Hashem1and Dr Shahab Pathan2, 1Senior Research Officer, and 2Research Officer, Department Agriculture and Food 14. Another case of glyphosate resistance in annual ryegrass confirmes within Western Australia, Dr Abul Hashem1and Dr Shahab Pathan2, 1Senior Research Officer, and 2Research Officer, Department Agriculture and Food 15. Glyphosate resistance in the northern NSW – implications for Western Australian farming systems, Andrew Storrie, Tamworth Agricultural Institute, NSW Department of Primary Industries ALTERNATIVES TO TRIFLURALIN, KNOCKDOWNS, TANK MIXES AND NOVEL USES 16. Alternative pre-emergent herbicides to trifluralin for annual ryegrass control, Mr David Minkey and Dr Abul Hashem, Department of Agriculture and Food, 17. Evaluation of a new pre-emergent herbicide alternative dor the control of trifluralin resistant Lolium rigidum Gaudin (annual ryegrass) in wheat and barley, Craig A. Ruchs, Syngenta Crop Protection Australia Pty Ltd and Dr Peter Boutsalis, University of Adelaide 18. Novel knockdown tank mixes: Results from 12 trials over four years, Shahab Pathan1, Abul Hashem2, Catherine Borger3, Nerys Wilkins and Julie Roche, Department of Agriculture and Food, Western Australia, and 3the University of Western Australia 19. Alternative herbicides for weed control in lupins, Peter Newman and Martin Harries, Department of Agriculture and Food 20. Novel use application of clopyealid in lupins, John Peirce, and Brad Rayner, Department of Agriculture and Food 21. A model to predict grass selective herbicide rates, John Moore, Department of Agriculture and Food CROP AND WEED MANAGEMENT 22. Inter-row weed control in wide row lupin using knockdown-based tank mixes, Dr Abul Hashem1, Ray Fulwood2 and Chris Roberts3, 1Senior Research Officer, Department of Agriculture and Food, 2Farmer, Meckering, WA, 3Technical Officer, Department of Agriculture and Food 23. Timing of weed removal in wide-row lupins, Sally Peltzer, Shahab Pathan and Paul Matson, Department of Agriculture and Food 24. The effect of row spacing and crop density on competitiveness of lupins with wild radish, Bob French and Laurie Maiolo, Department of Agriculture and Food 25. Is delayed sowing a good strategy for weed management in lupins? Bob French, Department of Agriculture and Food 26. Delayed sowing as a strategy to manage annual ryegrass, Department of Agriculture and Food HERBICIDE TOLERANCE 27. The effect of herbicides on nodulation in lupins, Lorne Mills1, Harmohinder Dhammu2 and Beng Tan1, 1Curtin University of Technology, and 2Department of Agriculture and Food 28. Response of new wheat varieties to herbicides, Harmohinder Dhammu, Department of Agriculture and Food 29. Herbicide tolerance of new barley varieties, Harmohinder Dhammu, Vince Lambert and Chris Roberts, Department of Agriculture and Food 30. Herbicide tolerance of new oat varieties, Harmohinder Dhammu, Vince Lambert and Chris Roberts, Department of Agriculture and Food OTHER WEEDY MATTERS 31. Research and extension need for wild radish and other cruciferous weeds, Aik Cheam, Department of Agriculture and Food 32. e-weed – an information resource of seasonal weed management issues, Vanessa Stewartand Julie Roche, Department of Agriculture and Foo

Exhumation history of the Qilian Shan, constrained by apatite U-Pb & fission track thermochronology

This item is only available electronically.The NW-SE trending Qilian Shan defines the NE border of Tibet and SE China. This study applies apatite U-Pb and low temperature thermochronology to constrain the exhumation history of the Qilian Shan through the Mesozoic-Cenozoic. AU-Pb and AFT analysis indicate that the eastern Qilian Shan has experienced a 3 stage cooling history since the early Mesozoic, consisting of: (i) rapid initial cooling during the late Triassic-early Jurassic (~240-170 Ma); (ii) either rapid cooling in the middle-late Cretaceous (~130-75 Ma) or a stage of quasi isothermal quiescence, depending on sample elevation and proximity to major E-W faults; and (iii) rapid subsequent cooling during the late Cenozoic (~30-10 Ma). Cooling in the late Triassic-early Jurassic is likely related to the closure of the Palaeo-Asian Ocean and/or the early Triassic Qiangtang collision to Eurasia. The middle-late Cretaceous cooling can be attributed to the collision of the Lhasa Block with southern Eurasia and/or subsequent extension within the Tethys Ocean due to slab roll-back. Finally, the late Cenozoic cooling can be related to the India-Eurasia Collision. Hence, the cooling histories obtained in this study indicate the Qilian Shan has undergone 3 main stages of exhumation in response to far-field tectonic events. Results obtained from this study support previous work done in the Qilian Shan area, improving the overall understanding of strain propagation through Central Asia.Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 201

Resistance to acetolactate synthase-inhibiting herbicides in Sonchus oleraceus, Sisymbrium orientale and Brassica tournefortii / Peter Boutsalis.

Bibliography: leaves 147-163.ix, 164 leaves : ill. (some col.) ; 30 cm.The aim of this thesis is to confirm the resistance status of three purported resistant weed species by herbicide screening of outdoor pot grown plants. Field experiments are set up to investigate changes in dormancy and seedbank life of the resistant populations over a three year period. After determining the herbicide resistance spectrum of the resistant biotypes, genetic crosses between resistant and susceptible plants are performed to follow the mode of inheritance of acetolactate synthase (ALS) resistance. "In vitro" ALS enzyme assays in the presence of various herbicides are carried out to reveal a modified ALS enzyme as the main mechanism of resistance in all cases. A molecular investigation of the ALS gene is performed to identify mutations responsible for endowing a resistant enzyme.Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 199

Resistance to acetyl-Coenzyme A carboxylase (ACCase)-inhibiting herbicides in Bromus spp. in Australia

Peter Boutsalis and Christopher Prestonhttp://www.weedinfo.com.au/bk_15awc.htm

Herbicide cross resistance in Bromus diandrus and B. rigidus populations across southeastern Australia

Herbicide resistance to Group A (AC Case-inhibiting herbicides) and B herbicides (ALSinhibiting herbicides) in Bromus diandrus and B. rigidus is becoming more common in southeastern Australia but there is limited information available on its regional distribution in either species. At present it is unclear if resistant brome populations differ in their response to different herbicides within the same herbicide group. Another unresolved question is related to the herbicide dose response of resistant brome populations. This study identified differences between Group A herbicides in their activity on resistant brome. However, increasing herbicide dose only marginally improved weed control in most cases. Varying degrees of Group B resistance was also detected in four brome populations. These initial findings suggest that increasing herbicide dose is unlikely to improve brome control but some Group A and B herbicides are more effective than others in controlling resistant populations.Peter Boutsalis, Christopher Preston and Gurjeet Gil

Distribution of herbicide-resistant acetyl-coenzyme A carboxylase alleles in Lolium rigidum across grain cropping areas of South Australia

Resistance to the acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides in Lolium rigidum is widespread in grain cropping areas of South Australia. To better understand the occurrence and spread of resistance to these herbicides and how it has changed with time, the carboxyl transferase (CT) domain of the ACCase gene from resistant L. rigidum plants, col- lected from both random surveys of the mid-north of Southern Australia over 10 years as well as stratified surveys in individual fields, was sequenced and target site mutations characterised. Amino acid substitutions occurring as a consequence of these target site muta- tions, at seven positions in the ACCase gene previously correlated with herbicide resistance, were identified in c. 80% of resistant individuals, indicating target site mutation is a common mechanism of resistance in L. rigidum to this herbicide mode of action. Individu- als containing multiple amino acid substitutions (two, and in two cases, three substitutions) were also found. Substitutions at position 2041 occurred at the highest frequency in all years of the large area survey, while substitutions at position 2078 were most common in the single farm analysis. This study has shown that target site mutations leading to amino acid substitu- tions in ACCase of L. rigidum are widespread across South Australia and that these mutations have likely evolved independently in different locations. The results indicate that seed movement, both within and between fields, may contribute to the spread of resis- tance in a single field. However, over a large area, the independent appearance and selection of target site mutations conferring resistance through herbicide use is the most important factor.J. M. Malone, P. Boutsalis, J. Baker, C. Presto

Control of rigid ryegrass in australian wheat production with pyroxasulfone

Abstract in English and SpanishIn Australia, most wheat is sown in a no-till system without prior cultivation where herbicides are applied prior to sowing and incorporated by the planter. Trifluralin has been the most widely used PRE herbicide to control rigid ryegrass. The objective of this research was to determine crop safety and efficacy of alternative mechanism of action PRE herbicides for rigid ryegrass control in no-till wheat production. Pyroxasulfone achieved 98% control with PRE applications. The alternative PRE herbicides tested alone and in mixtures occasionally resulted in a significant reduction in wheat emergence but not crop yield. Trifluralin treatments failed at sites having trifluralin-resistant rigid ryegrass. Pyroxasulfone and prosulfocarb plus S-metolachlor were effective for control of rigid ryegrass across all trials with control ranging from 64 to 94%. This research demonstrated that PRE applications of herbicides other than trifluralin such as pyroxasulfone and prosulfocarb plus S-metolachlor can be safely and effectively used to control rigid ryegrass in no-till wheat.=En Australia, la mayoría del trigo se siembra en un sistema de labranza cero sin cultivo previo donde los herbicidas son aplicados antes de la siembra e incorporados con la sembradora. Trifluralin ha sido el herbicida PRE más ampliamente usado para el control de Lolium rigidum. El objetivo de esta investigación fue determinar la seguridad para el cultivo y la eficacia de herbicidas PRE con mecanismos de acción alternativos para el control de L. rigidum en producción de trigo en labranza cero. Pyroxasulfone alcanzó 98% de control con aplicaciones PRE. Los herbicidas PRE alternativos evaluados solos y en mezclas ocasionalmente resultaron en una reducción significativa en la emergencia del trigo pero no del rendimiento del cultivo. Los tratamientos de trifluralin fallaron en sitios que tenían L. rigidum resistente a trifluralin. Pyroxasulfone y prosulfocarb más S-metolachlor fueron efectivos para controlar L. rigidum en todos los ensayos con un control que fluctuó entre 64 y 94%. Esta investigación demostró que aplicaciones PRE de herbicidas diferentes a trifluralin, tales como pyroxasulfone y prosulfocarb más S-metolachlor pueden ser usados en forma segura y efectiva para el control de L. rigidum en trigo en labranza cero.Peter Boutsalis, Gurjeet S. Gill, and Christopher Presto

Management of trifluralin resistance in annual ryegrass (Lolium rigidum Gaudin) in southern Australia

Peter Boutsalis, Christopher Preston and John Brosterhttp://www.weedinfo.com.au/bk_15awc.htm