THE prolonged dry conditions throughout much of the northern farming zone over the past two years have increased the risk of stubble- and soil-borne diseases impacting winter cereals this season, according to New South Wales Department of Primary Industries plant pathologist, Steven Simpfendorfer.
Speaking at the Grains Research and Development Corporation’s (GRDC) Grains Research Update in Goondiwindi, Dr Simpfendorfer said there was an elevated risk of diseases such as Fusarium crown rot and common root rot this year given the dry conditions which had prolonged the survival of pathogen inoculum.
“With the run of dry conditions, the lack of stubble breakdown means it is bringing cereal pathogens with it. Even stubble that looks degraded still has crown rot fungus at low levels. The consequences of a long dry is you are going to get the survival of stubble-borne pathogens,” he said.
He said disease risk could be a significant issue for the forthcoming winter crop, particularly as growers were likely to plant a lot more cereals this year.
“The lack of animal stock, failure of pastures and need for ground cover are likely to see a substantial increase in the area of cereals planted, especially in mixed farming systems once the drought breaks,” he said.
“There are therefore potentially higher risk paddocks for cereal diseases as the grasses serve as alternate hosts for pathogens such as Fusarium crown rot, common root rot, rhizoctonia root rot, take-all, root lesions nematodes and some leaf diseases.”
At the same time, there has been a decline in the populations of beneficial arbuscular mycorrhizae fungi (AMF).
Practical management options
Dr Simpfendorfer said there were practical steps producers could take to minimise the risk of disease impacting wheat and barley crops this season:
Step 1: Know before you sow
- Consider the long term sequences within paddocks
- Consider testing paddocks using PredictB
- Submit stubble or grass samples to NSW DPI laboratories
Step 2: Consider pre-sowing management options
- PredictaB test results offer generic management options
- Enlist accredited agronomists to assist with interpreting results
Step 3: Ensure quality of planting seed
- Test retained seed at least two months before sowing to ensure optimum germination
- Particular attention should be given to determining vigour of retained seed for sowing
Step 4: Assess infection levels and root health prior to head emergence
- Dig up plants around heading to inspect root health
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