Fungicide resistant wheat powdery mildew – management and resistance testing

2020 - 2021

Research organisaton
Funding source
Trengove Consulting

Trial details

Researcher(s) Sam Trengove
Contact email samtrenny34@hotmail.com
Contact phone 0428262057
Year(s) 2020 - 2021
Contributor Trengove Consulting
Trial location(s) Bute, SA
Fungicide resistant wheat powdery mildew – management and resistance testing locations
Aims

To better understand best practice management of WPM given emerging fungicide resistance issues.

For trial results please see attached report. 

Key messages

• 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
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
Download the trial report to view additional trial information

Method

Crop type Cereal (Grain): Wheat
Treatment type(s)
  • Fungicide: Timing
  • Fungicide: Type
Trial type Experimental
Trial design Randomised,Replicated,Blocked

Bute 2020

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication Not specified
Fungicide Not specified

Bute 2021

Sow date Not applicable
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.

Download the trial report to view additional method/treatment information
Trial source data and summary not available
Check the trial report PDF for trial results.
Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Bute, SA Not specified
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Bute, SA Calcarosol
National soil grid Source: CSIRO/TERN
NOTE: National Soil Grid data is aggregated information for background information on the wider area
Actual soil values can vary significantly in a small area and the trial soil tests are the most relevant data where available

Soil properties

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Climate

Derived climate information

No observed climate data available for this trial.
Derived climate data is determined from trial site location and national weather sources.

Bute SA

NOTE: Exact trial site locality unknown - Climate data may not be accurate
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Some data on this site is sourced from the Bureau of Meteorology

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.

Trial report and links

2021 trial report



Trial last modified: 05-01-2023 09:42am AEST