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Spring 2005
WAHRI NEWSRyegrass, the germination that was Laboratory weed seed research at WAHRI helps to explain one of the questions being asked in the Northern wheatbelt this year: why was the ryegrass germination so good? DAWA Weeds Research Officer Peter Newman explains how April rainfall could have as much as doubled the ryegrass that germinated at the break of the season. (link) Glyphosate resistance confirmed at new sites Glyphosate resistant ryegrass has been confirmed at four new locations in Australia but no new cases have been confirmed in WA. The new populations are now listed on the Australian Glyphosate Resistance Register, bringing the total number of populations to 44, with 24 of the cases in broadacre cropping. All are in annual ryegrass. more Research begins into low glyphosate rates and flow of resistance genes Dr. Roberto Busi from the University of Turin has joined WAHRI to begin research into how far ryegrass pollen can successfully carry herbicide resistance genes and the effects of low glyphosate use rates on the potential for glyphosate resistance in ryegrass. (link) Towards herbicide tolerant pulse crops A new collaborative GRDC funded project between CLIMA and WAHRI has recently commenced at UWA with the aim of identifying herbicide tolerant pulse crops. Research being conducted by Drs Michael Walsh and Ping Si will focus on screening pulse lines for tolerance to broad leaf herbicides that have high efficacy on wild radish. more Burning narrow windrows to destroy ryegrass and wild radish seed Researchers Michael Walsh and Peter Newman have found that a strategic burn of narrow windrows is an effective means of targeting the seed of both wild radish and annual ryegrass. Studies show narrow windrows are effective because of the large amount of material concentrated into a small area which increases the potential for destroying weed seeds by stubble burning. more The economics of avoiding glyphosate resistance Adopting a long-term double knockdown strategy to prevent glyphosate resistance developing over a 20 year period is likely to be profitable for many, but not all, grain growers. These are the results from a study at the University of Western Australia's School of Agricultural & Resource Economics, based on WAHRI resistance research. Situations where investing in the double knockdown strategy to prevent resistance is profitable for graingrowers are isdentified. Link to article or Crop Update paper Glyphosate Resistance: Frequently Asked Questions The national Glyphosate Sustainability Working Group, an initiative involving research institutions and herbicide companies from around Australia, has developed a set of easy-to-follow answers to commonly asked questions relating to glyphosate resistance, including what to do if you suspect glyphosate resistance. These can be found on the GSWG website together with the Australian Glyphosate Resistance Register which documents the confirmed glyphosate resistant populations in Australia. http://www.weeds.crc.org.au/glyphosate Glyphosate, trifluralin and no-till adoption The fall in glyphosate price over the past decade and expected trifluralin efficacy have been shown to be significant drivers of no-till adoption in cropping regions in southern Australia. The CRC Weeds funded study by Frank D’Emden and others in the School of Agricultural & Resource Economics showed that the expected benefits of no-till such as moisture conservation and more timely seeding were driving increased use of no-till, but the sustainability of weed management in no-till systems was a concern to growers using no-till link New WA study of herbicide resistance in wild oats Reports of increased wild oat populations and resistance problems are increasing in WA. A study of the extent and herbicide resistance status of wild oats across Western Australian cropping regions will be conducted by WAHRI this year. The survey will involve random sampling from cropping paddocks across the wheat belt during October. For more information contact Mechelle Owen Multiple resistant wild radish and trifluralin resistant ryegrass increasing in WA Wild radish: New survey results based on random collections from 503 paddocks show the level of resistance to chlorsulfuron (Glean) has increased 3 fold over the past 4 years, and of particular concern is the identification of populations developing resistance to Atrazine and 2,4-D-amine. more Ryegrass: The results show that levels of ryegrass resistant to Group A herbicides, including clethodim (Select), and Group B's have increased substantially since 1999, and resistance to trifluralin being identified in several populations more RIM in national workshops for advisors and growers The Resistance Integrated Management program (RIM) has been used extensively throughout Victoria as part of the DPI State Focus project. Over 250 growers and advisors used RIM as part of the program. RIM sessions are also part of a national IWM training program being conducted for advisors this year through the CRC Weeds and ICAN. For more information on organising a workshop using RIM for your group contact Robert Barrett Lennard Don’t cut herbicide rates WAHRI research using the Group A herbicide diclofop on annual ryegrass shows that cutting herbicide rates can lead to resistance in just four generations- including cross resistance to other herbicide groups. WAHRI Director, Professor Steve Powles, says that the implications are clear; growers should not cut rates below the label recommended rate, especially here in Australia where herbicide rates are already low by international standards Full article Distinction awarded to WAHRI PhD research Martin Vila Aiub received an award of Distinction from the Board of the Graduate Research School for his PhD thesis "Ecological fitness costs in a multiple herbicide-resistant Lolium rigidum population". WAHRI wishes to extend our congratulations to Martin for his outstanding achievement. New appointments for Pippa Michael and Dr. Kathryn Steadman WAHRI PhD student Pippa Michael has been appointed a Field Biologist for Syngenta in WA and WAHRI postdoc Dr. Kathryn Steadman has been appointed as Lecturer at Murdoch University (link) Latest WAHRI Journal Articles 2005 D'Emden, F. H., Llewellyn, R. S. and Burton, M.P. (2005) Adoption of conservation tillage in Australian cropping regions: An application of duration analysis. Technological Forecasting and Social Change (in press). Llewellyn, R.S. and Allen, D.M. 2005. Expected mobility of herbicide resistance via weed seeds and pollen in a Western Australian cropping region. Crop Protection 24 (in press). Llewellyn. R.S., Lindner, R.K., Pannell, D.J. Powles, S.B. (2005) The influence of extension on learning and doing. Agricultural Systems. (accepted) Llewellyn, R. S., Pannell, D. J., Lindner, R. K., Powles, S. B. (2005). Targeting key perceptions when planning and evaluating extension. Australian Journal of Experimental Agriculture (in press). Maneechote, C., Samanwong, S., Zhang, X., Powles, S.B. (2005) Resistance to ACCase inhibiting herbicides in a Thailand population of Leptochloa chinensis L. Weed Research, 53, 290-295. Monjardino, M., Pannell, D. J. and Powles, S. B. (2005) The economic value of glyphosate-resistant canola in the management of two widespread crop weeds in a Western Australian farming system. Agricultural Systems 84 (3) 297-315. Neve, P & Powles SB (2005) Recurrent selection with reduced herbicide rates results in the rapid evolution of herbicide resistance in olium rigidum. Theoretical and Applied Genetics,110, 1154-1166. Preston, C., Soar, C.J., Hidayat,I., Greenfield K.M., and Powles, S.B. (2005) Differential translocation of paraquat in paraquat-resistant populations of Hordeum leporinum. Weed Research, 45, 289-295. Vila-Aiub, M.M., Neve, P., Steadman, K.J., Powles, S.B. (2005) Ecological fitness of a multiple herbicide resistant Lolium rigidum population: Dynamics of seed germination and seedling emergence of target-site versus metabolism-based resistant and susceptible phenotypes. Journal of Applied Ecology, 42, 288-298. Vila-Aiub MM, Neve P & Powles SB. (2005) Fitness Costs of Evolved Herbicide Resistance. Encyclopedia of Pest Management, Marcel Dekker Inc., New York, (in press). Vila-Aiub MM, Neve P & Powles SB .(2005) Resistance costs of a cytochrome P450 herbicide metabolism mechanism but not an ACCase target site mutation in a multiple resistant Lolium rigidum population. New Phytology, 167, 787-796. Weersink, A., Llewellyn, R.S., Pannell, D.J. (2005). Economics of pre-emptive management to avoid weed resistance to glyphosate in Australia. Crop Protection, 24 (7), 659-665. |
