Research unlocks secrets to overcoming root disease

Crop productivity could be vastly improved, especially in high rainfall areas, as a result of new findings from research into root diseases in Western Australia.

The Department of Agriculture and Food has discovered that some soils possess biological disease suppressants – a revelation for scientists halfway through the four year project funded by the Grains Research and Development Corporation.

Soil diseases, like rhizoctonia root rot, take-all, fusarium crown rot and root lesion nematodes, cost WA grain growers $84 million each year in yield losses and quality.

Department research officer Shahajahan Miyan (photo) is seeking an understanding of what enables soils to suppress the incidence or severity of disease.



"Previous surveys have found there has not been a reduction in the incidence or severity of root diseases in WA during the past 25 years,” Mr Miyan said.

"But our analysis of cereal roots collected from 246 paddocks from across the Wheatbelt identified paddocks with various degrees of suppression.

"This included 14 for rhizoctonia, six for take-all, seventeen for crown rot and one for root lesion nematodes identified during two successive years, 2010-11.

"The research has found that the control identified as suppressive two years ago has continued to be suppressive in bioassays during two seasons.

"Five paddocks identified in our surveys express moderate suppression of disease severity in glasshouse bioassays.”

Department researchers are now examining what organisms are present in the disease suppressive soils, what is happening in the farming system and what intervention can be made to enhance these soils.

"These findings are very exciting,” Dr Miyan said. “They give us confidence that biological suppression could be a valuable tool to control these root diseases and increase crop production in the high rainfall zone.

"In the longer term, this research will contribute to the development of tools and farming systems guidelines that could encourage disease suppressive soils to boost crop productivity.”