Australia
March 6, 2019
Barley growers are being encouraged to use seed treatments prior to planting this season to reduce the risk of loose smut in their 2019 crops. Photo GRDC
Queensland and New South Wales barley growers are being encouraged to use seed treatments prior to planting to reduce the risk of loose smut in their 2019 crops.
Queensland Department of Agriculture and Fisheries (DAF) pathologist Lisle Snyman said despite the dry season in 2018 many barley growers on the Darling Downs had reported relatively high levels of loose smut (Ustilago nuda) in crops.
So this season she is warning growers to be proactive and treat seed ahead of planting to reduce the risk of the disease.
“It is difficult to achieve 100 per cent control, even with perfect application. But treating seed is still worthwhile and will prevent the disease from escalating. If seed is sourced from a crop known to have been infected with loose smut, it would be wise to treat seed at the higher recommended rate,” she said.
Dr Snyman said to keep smut under control, growers should use seed dressings every year and thorough application was critical, with every seed needing a treatment.
Grains Research and Development Corporation (GRDC) Crop Protection Officer – North, Vicki Green said the increased incidents of loose smut in barley in 2018 was a reminder to maintain effective fungicide treatment of planting seed.
“Using seed treatments are an important part of industry best practice, because they are one of the tools growers can use to assist in producing barley that meets market requirements.
“Some of our markets have nil tolerance for barley smut, which makes it critical we do whatever we can to manage the disease.”
Dr Snyman said all varieties of barley could be affected but varieties of the Hindmarsh (PBR) lineage e.g. Hindmarsh (PBR), La Trobe (PBR), Spartacus CL (PBR) and Rosalind (PBR), were more susceptible to the disease.
“Loose smut is most conspicuous around flowering when infected heads bearing a mass of dark brown to black sooty spores are visible among the green heads of unaffected plants. This stark contrast in colour can lead to exaggerated estimates of infected heads,” she said.
“Losses in yield equate to the percentage of infected heads and the detection of greater than 0.1g of loose smut particles in a half litre harvest sample will result in rejection of grain deliveries.”
Several fungicides are registered for the control of loose smut.
Reducing risk of loose smut in barley:
- Choose less susceptible varieties.
- Treat planting seed with an effective fungicide.
- Thorough application of fungicide is critical - application machinery must be well calibrated, fungicide suspensions continuously agitated and seed mixed thoroughly to ensure even distribution of chemical on the seed.
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