What’s Happening?
Queensland researchers have uncovered a potential weakness in barley disease management. Their findings suggest planting seed could carry fungicide-resistant net blotch into future crops.
A University of Southern Queensland (UniSQ) study found that the disease can move from infected seed into developing seedlings.
The discovery raises concerns about an overlooked pathway for fungicide resistance between cropping seasons.
Why It Matters
Barley growers use several methods to control net blotch. These include choosing less-susceptible varieties, reducing sources of infection and managing fungicide use. However, planting seed may introduce additional disease risks despite these precautions.
Lead researcher Dr Noel Knight said growers should also consider where their planting seed comes from.
“Seed isn’t just planting material. It can be a disease-management decision,” Dr Knight said.
The findings do not change existing recommendations. Instead, they highlight seed source as another consideration for disease management.
Local Impact
The findings add to Queensland’s understanding of fungicide resistance in barley crops.
Researchers examined seedlots from grower fields across the Darling Downs. Their work identified a potential pathway for disease to move between cropping seasons.
The discovery also suggests growers may eventually benefit from identifying lower-risk planting seed.
However, researchers need more evidence before they can establish the wider significance of this risk.
By The Numbers
- 16 seedlots: Researchers examined barley seed from grower fields across the Darling Downs.
- 10–40%: Net blotch can reduce barley grain yields by this amount. Severe outbreaks can cause even greater losses.
- $190 million: Queensland’s barley industry contributes approximately this amount to the state’s economy each year.
Zoom In
Researchers tested barley seed for net blotch and markers linked to reduced fungicide sensitivity.
They detected net blotch pathogen DNA in 13 seedlots. Next, they planted one of the higher-risk seedlots and monitored the seedlings.
The team later found the same reduced-sensitivity types in net blotch lesions on the seedlings. This provided evidence that fungicide-resistant net blotch can move from seed into a new crop.
Dr Knight explained why the discovery matters for growers who already take precautions.
“If growers are doing everything recommended to manage disease but unknowingly plant seed carrying both the pathogen and reduced fungicide sensitivity, they could be introducing additional disease risk at the start of the season,” he said.
Zoom Out
The findings suggest seed testing could eventually help growers make more informed planting decisions.
Three seedlots showed no detectable net blotch. This suggests researchers may be able to identify lower-risk seed.
However, growers cannot currently access seed testing for net blotch and fungicide resistance. Dr Noel Knight, Dr Barsha Poudel and Professor Levente Kiss conducted the research at UniSQ’s Centre for Crop Health.
The study forms part of the Broadacre Cropping Initiative. UniSQ and the Queensland Department of Primary Industries jointly fund the initiative.
What To Look For Next?
The researchers are preparing their findings for publication. Further studies will examine how widespread seedborne fungicide resistance is and how often transmission occurs across seasons.
Researchers also want to understand how environmental conditions influence the process. Dr Knight stressed that growers should not view the discovery as a reason for alarm.
“Rather than sounding the alarm, we’re adding another piece to the puzzle and giving growers another consideration to manage disease risk.”
