Australia
November 7, 2014

By GRDC western regional panel member Chris Wilkins

Detections of fusarium crown rot in Western Australian cereal crops have increased this season, particularly in central and northern cropping regions.

This follows more intensive cereal production and favourable seasonal conditions in 2013 and 2014.

The Department of Agriculture and Food (DAFWA) has reported constant demand this season on its diagnostic service, AGWEST Plant Laboratories (APL), to identify root diseases including crown rot present in samples.

Crown rot was also raised as an issue by growers with Grains Research and Development Corporation (GRDC) western panel members during the panel’s recent spring tours and at field days.

The GRDC is funding a range of DAFWA trials to assess cereal variety tolerance to crown rot and improved management strategies through its new national project ‘National crown rot epidemiology and management’.

In 2014, a three-year WA trial program was started to assess yield loss in wheat and barley due to crown rot and other research is looking at rotation benefits and inter-row sowing to improve cereal crop yields.

The GRDC’s national crown rot project will also continue to investigate genetic solutions to this fungal disease by breeding more resistant cereal varieties and undertake molecular research to unravel how the crown rot pathogen causes disease.

The key message to growers from DAFWA researchers including Daniel Hüberli and Shahajahan Miyan is to test wheat and barley crops before or at harvest if they are showing signs of crown rot or other soilborne diseases and pests such as rhizoctonia bare patch and root lesion nematodes (RLN).

Different soilborne diseases and pests need different management strategies, so it is vital to know what is present in the paddock.

The GRDC and DAFWA-developed MyCrop ‘app’ can assist with disease diagnosis and is available at www.agric.wa.gov.au/mycrop.

Plant and stubble samples can be sent to APL for correct identification of any crown or root diseases or RLN pests. Information about APL is available at www.agric.wa.gov.au/n/1766.

After harvest and into autumn, the SARDI PreDicta-B® soil test which is available through accredited agronomists, can also diagnose the presence of these diseases and pests in suspect paddocks.

According to Dr Hüberli, testing this year will help with rotation planning for 2015, as crop choice following cereals is a major management tool to break disease and pest cycles.

There are currently no registered fungicides to control crown rot and rotation with non-cereals is the key management tool for affected paddocks. This means 2014 observations will be critical for break-crop planning for 2015.

If plant or soil testing detects paddocks with a high risk of crown rot for next year, the best options are:

• Sowing a non-cereal break crop, such as canola or pulses;
• Ensuring good grass weed control over summer and in break crops;
• Using inter-row sowing if sowing cereals into standing cereal stubble;
• Minimising stubble cultivation, spreading, slashing or grazing this summer (this can spread infected residues over paddocks). Burning stubbles can help reduce crown rot but will not eliminate it, as the disease is carried in the crown of affected plants;
• Using less susceptible cereal varieties, such as Emu Rock, and sowing early so crops are less vulnerable to a hard finish (which causes the expression of white heads). Ratings of susceptibility will be added to future GRDC-DAFWA Wheat and Barley variety guides when data from trials that started this year are completed.

More information about crown rot can be found on the DAFWA website at www.agric.wa.gov.au/n/2131 and at the GRDC Hot Topic Managing Crown Rot in WA at www.grdc.com.au/ManagingCrownRotWA
 

Website: http://www.grdc.com.au

Published: November 7, 2014