Seed testing and dressings key smut strategies

Author: Natalie Lee | Date: 09 Nov 2017

Smut in a barley crop

Caption: Loose smut in Hindmarsh barley . Photo by Andrea Hills, DPIRD.

Western Australian barley growers concerned that high levels of loose smut will be carried over into next year’s crops are encouraged to test retained seed for the disease following this harvest and to use seed dressings prior to sowing barley in 2018.

Department of Primary Industries and Regional Development (DPIRD) researcher Andrea Hills said barley growers, particularly in medium to high rainfall areas, experienced high levels of barley loose smut (Ustilago nuda) this year.

She said all varieties could be affected but growers of Hindmarsh , and its sister line, La Trobe , were more likely to be impacted by the disease, which reduces grain yield and affects export opportunities for some markets.

Ms Hills, who conducts DPIRD research into loose smut as part of a Grains Research and Development Corporation (GRDC) crop disease investment in WA, urged growers who were concerned about smut levels to assess them in spring each year.

“In most cases, levels of the disease are actually much lower than they appear,” she said.

“The disease can in most cases be profitably managed, so growers should not be unnecessarily alarmed.

“Having said this, as seed infection occurs during flowering, the long, cool spring in 2016 may have led to higher than usual infection rates of seeds used to sow 2017 barley crops.”

Ms Hills said good growing conditions in a number of southern areas of WA in 2017 meant more infected seed survived to produce smutted heads.

“This year’s spring has been relatively favourable for loose smut transmission and renewed infection in many barley growing areas, so smut levels might be high again next year,” she said.

Ms Hills said testing seed retained at harvest would give growers a better idea of what they might face if they did not treat it carefully with a premium seed dressing. The results of product efficacy trials are available via this link.

“If seed is tested and found to be at or higher than the 5 per cent infection level, growers may benefit from replacing it with a new batch of seed – for example from the lower rainfall area which usually has lower levels of smut,” she said.

Ms Hills said to keep smut under control, growers should use seed dressings every year and application was critical, with every seed needing a dose.

Caption: Close-up image of loose smut in BaudinPlant breeders rights for word docs barley during a past season at Avondale Agriculture Research Station. Photo by DPIRD.

“It is worth noting we cannot prevent seed from becoming infected with loose smut, and seed dressings can only control the smut that is already present in the grain,” she said.

“Also, no seed dressing can be expected to give 100 per cent control, even with perfect application.

“However, treating seed is still worthwhile and stops the problem from escalating.”

Ms Hills said all seed dressings reduced loose smut, but in 2013 DPIRD trials some premium products controlled it at the 99 per cent level.

“However, at a paddock scale, even with 99.9 per cent control and perfect application, at a 70kg/ha sowing rate of ‘average’ La Trobe  sized seed that has a 1 per cent level of infection, there will still be 1.4 infected plants for every 30 by 30 metre square,” Ms Hills said.

More information about barley loose smut management is available by searching the DPIRD website.

Growers wishing to test seed can contact DPIRD Diagnostic Laboratory Services (previously AGWEST Plant Laboratories) on 08 9368 3351 or ddls@agric.wa.gov.au

Contact Details

For Interviews
Andrea Hills, DPIRD
0488 575 091
andrea.hills@dpird.wa.gov.au

Contact
Natalie Lee Cox Inall Communications
0427 189 827
natalie.lee@coxinall.com.au