| Researcher(s) |
Geoff Thomas (DAFWA) |
|---|---|
| Year(s) | 2016 |
| Contributor | West Midlands Group |
| Trial location(s) |
Moora, WA
|
To investigate the efficacy of seed dressing and fertiliser applied fungicides on the time of onset, rate of development and yield impact of wheat powdery mildew.
At the time of first visit (30th May), plants were at ~3 leaf stage and no foliar disease was evident. Seedling establishment showed no spatial differences, with average emergence of >100 plants / m2 in all treatments except those with triadimenol seed treatment where >20% reduction in emergence was noted.
Minimal foliar disease was evident at 7th July (~Z31) assessment, minor levels of Stagonospora nodorum (septoria nodorum blotch) (SNB) were evident in the lower canopy but severity was too low for fungicide differences to be assessed.
Trace levels of powdery mildew (PM) were evident on stems and lowest canopy leaves of untreated plots at booting (27th July) when the second foliar spray was applied. Development of PM was slow and on 15th September (~Z69) average severity in untreated controls was <1% leaf area affected on top 3 leaves, with infection primarily restricted to Flag-2 (Table 1).
PM was also present on heads and stems at low severity at this time, however the distribution of disease, particularly on heads, was patchy across the trial making differentiating between treatments difficult. At this time only the booting foliar spray provided consistent significant reduction in incidence of powdery mildew on stems and leaves.
SNB was present at low levels throughout the season, assessments at head emergence (23rd August) showed a small but significant effect of foliar treatments (Z31 and Z45) and flutriafol and Uniform in-furrow on necrotic leaf area. Assessments 3 weeks later at Z69 indicated that flutriafol in-furrow, triadimenol seed dressing and both foliar spray timings were providing a small reduction (~8-15% leaf area) in necrosis associated with SNB infection (Table 1).
With late and patchy onset of PM, yield responses to fungicides were 0-320kg/ha, with only the flutriafol in-furrow treatment having significantly greater yield than the untreated control, this response is likely due to the reduction of SNB rather than any effect on powdery mildew. Neither foliar spray timing gave significant yield response. Reduced emergence in triadimenol treated plots resulted in a 15% yield reduction (Table 2).
At two other sites (Geraldton, Dalwallinu), where powdery mildew infection commenced during stem elongation, all tested seed dressing and in-furrow fungicides had significant impact on disease severity and incidence. At the one site (Geraldton) where powdery mildew was yield limiting, in-furrow and foliar fungicide treatments gave a significant yield response.
| Lead research organisation |
Department of Agriculture and Food WA |
|---|---|
| Host research organisation |
West Midlands Group |
| Trial funding source | GRDC DAW00229 |
| Related program | N/A |
| Acknowledgments |
DAFWA research support unit Geraldton (S.Cosh, T.Bell) for trial management. Michael Brennan and West Midlands Group (Moora) for site DAFWA and GRDC (DAW00229) for funding. Companies (BASF, Bayer, Four farmers, Syngenta) for product treatments. |
| Other trial partners | Not specified |
| Crop type | Cereal (Grain): Wheat |
|---|---|
| Treatment type(s) |
|
| Trial type | Experimental |
| Trial design | Randomised,Replicated,Blocked |
| Sow date | 4 May 2016 |
|---|---|
| Harvest date | Not specified |
| Plot size | 20m x 7m |
| Plot replication | 3 |
| Psuedoreplication | Not specified |
| Fungicide |
Factor 1. Early season treatments 1. Untreated 2. Untreated 3. Prosaro® 150ml/ha at Z31 (7th July) 4. Flutriafol in-furrow (Flutriafol 250® 400mL/ha) 5. Fluquinconazole on seed (Jockey Stayer® 450mL/100kg seed) 6. Fluxapyroxad on seed (Systiva® 150mL/100kg seed) 7. Triadimenol (Baytan T® 150mL/100kg seed) 8. Triadimefon in-furrow (Triadimefon 500 Dry® 200g/ha) 9. Azoxystrobin & Metalaxyl-M in-furrow (Uniform® 400mL/ha) & |
| Rainfall trial gsr (mm) | 269mm |
|---|
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.
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