Barley powdery mildew a focus for research
By GRDC western regional panel member Chris Wilkins
Western Australian farmers planning to grow barley this season have a few things to consider in order to minimise crop losses from powdery mildew.
Along with barley leaf rust, powdery mildew is one of the major diseases of barley in WA in terms of management costs and production losses.
Powdery mildew thrives in warm, moist conditions and can occur as early as May if growers plant barley after an early break to the season.
The Grains Research and Development Corporation (GRDC) invests significant funds into barley disease research. A major focus for this investment is the $100 million Centre for Crop and Disease Management (CCDM) at Curtin University, WA.
The centre is the first bilateral research agreement between the GRDC and an Australian university and is focused on targeted RD&E to reduce the production losses caused by crop diseases.
Resistance ratings research carried out by the CCDM team in 2013, accompanying
Department of Agriculture and Food (DAFWA) field trials, confirmed that most barley varieties grown in WA are susceptible to powdery mildew.
The work also identified new strains of the disease and found that virulence exists against most major resistance genes present in WA barley varieties.
Researchers believe that some currently resistant varieties may become susceptible to powdery mildew in the future.
Barley powdery mildew has also evolved resistance in recent years to older triazoles (DMIs), although the newer triazoles and strobilurins still provide effective control.
These factors mean that growers will need to make sure they manage this disease with all measures possible.
Variety choice is important in getting the best performance from your barley crop and management for powdery mildew will depend on which variety you choose.
Researchers advise growers to choose varieties that are less susceptible to the disease in areas where it is a threat.
If 2014 is wet, growers should monitor all barley crops for changes in mildew response.
Growers in coastal and southern regions with a history of mildew should also use suitable seed dressings and foliar applications if growing more susceptible varieties.
All fungicides, especially strobilurin products, are best used prior to significant disease levels appearing in crops.
It is important to rotate fungicide modes of action and/or active ingredients in a group and use fungicides as a protectant, rather than a curative.
Where powdery mildew occurs, samples should be sent to the CCDM for testing (contact Simon Ellwood at firstname.lastname@example.org).
More information about managing powdery mildew can be found in the:
- GRDC Barley Powdery Mildew fact sheet at www.grdc.com.au/GRDC-FS-BarleyPowderyMildew;
- GRDC Ground Cover supplement Emerging issues with diseases, weeds and pests at www.grdc.com.au/GCS102
- DAFWA Fact Sheet: Managing Barley Powdery Mildew in 2013 at http://www.agric.wa.gov.au/objtwr/imported_assets/content/pw/ph /dis/managing_barley_powdery_mildew_in_2013.pdf
GRDC Project Code CUR00016, CUR00017, DAW00224, DAW00229