RHIZOCTONIA is estimated to cost the cereal industry up to $77 million a year Australia-wide and can reduce crop yields by up to 70 per cent, depending on the severity of the infestation.
But a three-year research project is proving it is possible to reduce the losses caused by the soil-borne fungus by using new fungicides and application methods.
This year, trials to evaluate liquid banding of fungicides to control rhizoctonia bare patch in cereals are being run at three sites in South Australia: Lameroo, Wynarka and Weetulta, with trials also being replicated in Western Australia.
At the Lameroo site last month, as part of the GRDC Grains Research Update for Growers at Lameroo, SARDI senior research agronomist Paul Bogacki took the opportunity to explain to growers the promising results seen across the trials in 2013 which is the third and final year of the project.
"Rhizoctonia thrives in dry conditions and has been very prevalent this year due to last year's dry spring and this year's dry summer," he said.
"It is especially prevalent and more damaging in sandy soil types, which we have at our Wynarka and Weetulta sites," he said "However, heavier soil types like we have at Lameroo are also conducive to high rates of infection under the right conditions.
"Treatment effects are clearly visible at the Wynarka trial, and these have been backed up by our root and canopy assessments."
The fungus damages crown and seminal roots on crops, impairing the plant's ability to uptake nutrients and water. "It savages the root system," Dr Bogacki said. "It has always been present in the lower rainfall districts but has become more of an issue since the advent of no-till."
The trials have investigated liquid banding applications of new coded fungicides: using seed treatments as controls, banding fungicide in-furrow below the seed, banding fungicide on the soil surface, and a split application - with half the recommended rate banded below the seed and half on the soil surface.
Dr Bogacki said of the three banding methodologies the split application had shown the most promising results. "In previous years we have seen significant yield responses of up to 16per cent," he said.
"We are confident of matching and even bettering those responses in some of this year's trials."
Full report in Stock Journal, September 5 issue, 2013.
