Crop Updates 2009 - Weeds

This session covers twenty three papers from different authors: Herbicides 1. New pre-seeding grass selective herbicides – How well do they work in zero or no-till systems? Dr Catherine Borgerand Dr Abul Hashem, Department of Agriculture and Food 2. Velocity®—An alternate mode of action for the control of wild radish in cereals, Mike Clarke, Bayer Cropscience Pty Ltd, Dr Aik Cheam, Department of Agriculture and Food, Dr Michael Walsh, WAHRI, University of Western Australia 3. Herbicide tolerance of new barley varieties, Harmohinder Dhammu, Vince Lambert, Chris Roberts and Russell Quartermaine, Department of Agriculture and Food 4. Herbicide tolerance of Desi chickpea – influence of seeding depth and rainfall, Harmohinder Dhammu, and David Nicholson, Department of Agriculture and Food 5. Herbicide tolerance of new wheat varieties, Harmohinder Dhammu, and David Nicholson, Department of Agriculture and Food 6. PARAGON plus Bromicide 200: a triple mode-of-action approach to combating wild radish, Raphanus raphanistrum, Mike Jackson and Bill Campbell, Nufarm Australia Limited 7. Interaction of glyphosate dose, annual ryegrass growth stage and environmental conditions on the performance of glyphosate for control of annual ryegrass, John Moore, Abul Hashem, Mario D’Antuono, Paul Matson and Dave Nicholson, Department of Agriculture and Food 8. Metribuzin pre-sowing of lupins, Peter Newman, Department of Agriculture and Food 9. Wild radish herbicides - you get what you pay for, Peter Newman, Department of Agriculture and Food 10. Glyphosate-the consequences of cutting rates, Sally Peltzer and Dave Minkey, Department of Agriculture and Food, and Australian Herbicide Resistance Initiative 11. Reasons to use only the full label herbicide rate, Stephen B Powles, Qin Yu, Mechelle Owen, Roberto Busi and Sudheesh Manalil, WA Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia 12. Mandelup has reasonable tolerance to atrazine, Leigh Smith and Peter White, Department of Agriculture and Food Herbicide resistance 13. Risk of glyphosate resistance in wide-row lupin cropping systems, Fiona Evans, Abul Hashem and Art Diggle, Department of Agriculture and Food 14. More glyphosate-resistant annual ryegrass populations within Western Australia, Dr Abul Hashem and Dr Catherine Borger, Department of Agriculture and Food 15. Western Australian farmers are sowing herbicide-resistant weed seed into their cropping paddocks! Mechelle Owen1, Pippa Michael2and Stephen Powles1, 1WA Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, 2Muresk Institute, Curtin University of Technology Integrated Weed Management 16. Inversion ploughing: Effects of long-term deep burial on weed seed reserves, Aik Cheam and Siew Lee, Department of Agriculture and Food 17. How long cam wild radish seeds survive in the soil? Aik Cheam and Siew Lee, Department of Agriculture and Food 18. An economic comparison of IWM tools, Rob Grima, Department of Agriculture and Food 19. Emerging weeds in changing farming systems, Dr Abul Hashem, Department of Agriculture and Food 20. Eight years of IWM smashes ryegrass seed banks by 98 per cent over 31 focus paddocks, Peter Newman, Glenn Adam and Trevor Bell, Department of Agriculture and Food 21. Mouldboard plough - the answer to all the problems with sandplain farming! Peter Newman and Steve Davies, Department of Agriculture and Food 22. Flaxleaf fleabane - coming to a property near you! Sally Peltzer, Department of Agriculture and Food, 23. Trimming weed seed heads and crop-topping reduce seed bank of wild radish, Glen Riethmuller and Abul Hashem, Department of Agriculture and Foo

Broad Resistance to ACCase Inhibiting Herbicides in a Ryegrass Population Is Due Only to a Cysteine to Arginine Mutation in the Target Enzyme

BACKGROUND: The design of sustainable weed management strategies requires a good understanding of the mechanisms by which weeds evolve resistance to herbicides. Here we have conducted a study on the mechanism of resistance to ACCase inhibiting herbicides in a Lolium multiflorum population (RG3) from the UK. METHODOLOGY/PRINCIPAL FINDINGS: Analysis of plant phenotypes and genotypes showed that all the RG3 plants (72%) that contained the cysteine to arginine mutation at ACCase codon position 2088 were resistant to ACCase inhibiting herbicides. Whole plant dose response tests on predetermined wild and mutant 2088 genotypes from RG3 and a standard sensitive population indicated that the C2088R mutation is the only factor conferring resistance to all ten ACCase herbicides tested. The associated resistance indices ranged from 13 for clethodim to over 358 for diclofop-methyl. Clethodim, the most potent herbicide was significantly affected even when applied on small mutant plants at the peri-emergence and one leaf stages. CONCLUSION/SIGNIFICANCE: This study establishes the clear and unambiguous importance of the C2088R target site mutation in conferring broad resistance to ten commonly used ACCase inhibiting herbicides. It also demonstrates that low levels "creeping", multigenic, non target site resistance, is not always selected before single gene target site resistance appears in grass weed populations subjected to herbicide selection pressure

Crop Updates 2009 - Weeds

This session covers twenty three papers from different authors: Herbicides 1. New pre-seeding grass selective herbicides – How well do they work in zero or no-till systems? Dr Catherine Borgerand Dr Abul Hashem, Department of Agriculture and Food 2. Velocity®—An alternate mode of action for the control of wild radish in cereals, Mike Clarke, Bayer Cropscience Pty Ltd, Dr Aik Cheam, Department of Agriculture and Food, Dr Michael Walsh, WAHRI, University of Western Australia 3. Herbicide tolerance of new barley varieties, Harmohinder Dhammu, Vince Lambert, Chris Roberts and Russell Quartermaine, Department of Agriculture and Food 4. Herbicide tolerance of Desi chickpea – influence of seeding depth and rainfall, Harmohinder Dhammu, and David Nicholson, Department of Agriculture and Food 5. Herbicide tolerance of new wheat varieties, Harmohinder Dhammu, and David Nicholson, Department of Agriculture and Food 6. PARAGON plus Bromicide 200: a triple mode-of-action approach to combating wild radish, Raphanus raphanistrum, Mike Jackson and Bill Campbell, Nufarm Australia Limited 7. Interaction of glyphosate dose, annual ryegrass growth stage and environmental conditions on the performance of glyphosate for control of annual ryegrass, John Moore, Abul Hashem, Mario D’Antuono, Paul Matson and Dave Nicholson, Department of Agriculture and Food 8. Metribuzin pre-sowing of lupins, Peter Newman, Department of Agriculture and Food 9. Wild radish herbicides - you get what you pay for, Peter Newman, Department of Agriculture and Food 10. Glyphosate-the consequences of cutting rates, Sally Peltzer and Dave Minkey, Department of Agriculture and Food, and Australian Herbicide Resistance Initiative 11. Reasons to use only the full label herbicide rate, Stephen B Powles, Qin Yu, Mechelle Owen, Roberto Busi and Sudheesh Manalil, WA Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia 12. Mandelup has reasonable tolerance to atrazine, Leigh Smith and Peter White, Department of Agriculture and Food Herbicide resistance 13. Risk of glyphosate resistance in wide-row lupin cropping systems, Fiona Evans, Abul Hashem and Art Diggle, Department of Agriculture and Food 14. More glyphosate-resistant annual ryegrass populations within Western Australia, Dr Abul Hashem and Dr Catherine Borger, Department of Agriculture and Food 15. Western Australian farmers are sowing herbicide-resistant weed seed into their cropping paddocks! Mechelle Owen1, Pippa Michael2and Stephen Powles1, 1WA Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, 2Muresk Institute, Curtin University of Technology Integrated Weed Management 16. Inversion ploughing: Effects of long-term deep burial on weed seed reserves, Aik Cheam and Siew Lee, Department of Agriculture and Food 17. How long cam wild radish seeds survive in the soil? Aik Cheam and Siew Lee, Department of Agriculture and Food 18. An economic comparison of IWM tools, Rob Grima, Department of Agriculture and Food 19. Emerging weeds in changing farming systems, Dr Abul Hashem, Department of Agriculture and Food 20. Eight years of IWM smashes ryegrass seed banks by 98 per cent over 31 focus paddocks, Peter Newman, Glenn Adam and Trevor Bell, Department of Agriculture and Food 21. Mouldboard plough - the answer to all the problems with sandplain farming! Peter Newman and Steve Davies, Department of Agriculture and Food 22. Flaxleaf fleabane - coming to a property near you! Sally Peltzer, Department of Agriculture and Food, 23. Trimming weed seed heads and crop-topping reduce seed bank of wild radish, Glen Riethmuller and Abul Hashem, Department of Agriculture and Food