Researcher(s) |
Sam Trengove |
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Contact email | samtrenny34@hotmail.com |
Contact phone | 0428262057 |
Year(s) | 2020 - 2021 |
Contributor | Trengove Consulting |
Trial location(s) |
Bute, SA
|
To better understand best practice management of WPM given emerging fungicide resistance issues.
For trial results please see attached report.
• Varietal resistance plays an important role in managing wheat powdery mildew. The variety Grenade CL PlusA (MS) had less powdery mildew infection in the untreated than Chief CL PlusA and ScepterA (SVS) treated with a two-spray fungicide strategy.
• Wheat powdery mildew resistance mutation frequency increased from 2019 to 2021. In the northern Yorke Peninsula region in 2019, more than half the paddocks surveyed had no group 11 QoI (strobilurin) resistance mutation, whereas in 2021, all 30 paddocks sampled had some level of resistance mutation with the median resistance frequency increasing from 0 to 19%.
• Group 11 QoI resistance mutation has been detected at lower levels in the central Yorke Peninsula and Mid North regions in 2021.
• In a fungicide product trial, the application of group 11 QoI fungicides increased the frequency of resistance mutation from 19% in the untreated control to 48.5% on average across QoI treatments.
• The presence of group 11 resistance mutations meant that the performance of group 3 + 11 fungicide mixtures was generally not any better than the straight group 3 (DMI triazole) fungicides.
• Group 7 SDHI fungicides did not provide any additional control to the standalone group 3 DMI fungicides when applied in product mixtures. This is due to poor efficacy of group 7 fungicides on wheat powdery mildew, with no resistance to this fungicide group identified in these powdery mildew populations.
• Mutation at Cyp51 is a gateway mutation that infers reduced sensitivity to the group 3 DMI fungicides is likely, though the actual mutations conferring resistance are not known. High frequency of the Cyp51 mutation has commonly been encountered at trial sites, yet the group 3 DMI fungicides are currently providing the best fungicidal control, albeit incomplete control.
Lead research organisation |
Trengove Consulting |
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Host research organisation | N/A |
Trial funding source | SAGIT TC120 |
Related program | N/A |
Acknowledgments |
The research undertaken as part of this project is made possible by the significant contributions of growers through both trial cooperation and the support of the SAGIT, the authors would like to thank them for their continued support. The input during this project from Michael Brougham, Hugh Wallwork, Tara Garrard and Nick Poole is gratefully acknowledged. |
Other trial partners | SAGIT |
Crop type | Cereal (Grain): Wheat |
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Treatment type(s) |
|
Trial type | Experimental |
Trial design | Randomised,Replicated,Blocked |
Sow date | Not specified |
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Harvest date | Not specified |
Plot size | Not specified |
Plot replication | Not specified |
Fungicide | Not specified |
Sow date | Not applicable |
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Harvest date | Not applicable |
Plot size | 10m X 1.5m |
Plot replication | 3 |
Fungicide |
Post emergent fungicide treatments were applied using 015110 pre orifice nozzles in 100L of water. |
SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.