Timely septoria control boosts oat profitability
Date: 22 Jun 2015
By GRDC western regional panel member Shauna Stone
Research has shown that foliar fungicides can significantly reduce the severity of the disease septoria blotch in Bannister oats and applications around the time of flag leaf emergence appear to be most effective.
In a high rainfall environment, yield responses of up to 0.6 tonnes per hectare were achieved in this newer variety after tactical fungicide use.
The field trials also showed that septoria staining on the leaf was not strongly linked to grain staining in this variety.
ConsultAg conducted the 2014 trials as part of a project funded by the Grains Research and Development Corporation (GRDC) through the Kwinana West Regional Cropping Solutions Network (RCSN).
Bannister, bred for Western Australian conditions through the GRDC-supported National Oat Breeding Program, has higher stem rust and leaf rust resistance than the other main oat varieties grown in the State, but it still rated as susceptible (S) to septoria.
In its first commercial growing season in 2013, which saw a wet spring in many WA oat growing areas, significant septoria infection was observed in this variety and many oats delivered for grain were rejected due to grain discolouration.
To help assess the impact of septoria on Bannister yield and grain quality, the GRDC RCSN trials were conducted at a high rainfall site at Highbury and a medium rainfall site at Wagin in the Great Southern region.
The trials were set up in Bannister crops sown on oat stubbles to increase disease pressure and assessed single and double propiconazole applications at different timings.
Ashton Gray, of ConsultAg, says fungicide timing had a significant impact on the severity of leaf blotching caused by septoria at both sites.
ConsultAg’s economic analysis indicated either a single spray at flag leaf emergence, or a two-spray approach – at stem elongation and again at flag leaf emergence – could be economic in years with a wet finish and heavier disease pressure when infection occurred at/after stem extension.
The two-spray treatment increased yields by 0.6t/ha at Highbury, and the higher yields and better quality grain at this high yielding site increased returns by $140-215/ha across all treatments compared with the untreated control.
Mr Gray says that in lower disease situations, where infection hits the canopy later in the season, a single application at or around flag leaf emergence is likely to be able to protect crop leaves, help prevent infection developing in the mid and upper canopy and provide a yield benefit.
The trials showed that seasonal conditions from the grain fill stage to harvest appeared to have a significant impact on fungal grain staining, but applying late fungicides after head emergence seemed to be an unreliable method to reduce overall grain staining.
The GRDC RCSN project complements oat agronomy research conducted by DAFWA under the GRDC funded project ‘Tactical break crop agronomy for the western region’.
This five-year project aims to ensure WA’s valuable oat grain and hay industries are provided with the latest variety, agronomy and management information.
More information about oat agronomy is available on the DAFWA website.
Ashton Gray, ConsultAg
08 9881 5551, 0429 930 074
Shauna Stone, GRDC western panellist
0429 455 218
Natalie Lee, Senior Consultant, Cox Inall Communications
08 9864 2034, 0427 189 827
GRDC Project Code TAR0003, DAW00277