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Research Aims To Cut Root Disease Costs

10 August 2011

AUSTRALIA - Which farm management practices foster the ‘good' micro-organisms that reduce the impact of cereal root diseases? Western Australian researchers are a step closer to answering this question, having identified several paddocks which potentially suppress diseases including take-all, crown rot and rhizoctonia barepatch, and pests like root lesion nematode (RLN).

The research is funded by the Grains Research and Development Corporation (GRDC) and is being conducted by the Department of Agriculture and Food (DAFWA).

DAFWA researcher Daniel Hüberli said disease suppression was the ability of soil to suppress the incidence or severity of disease, even in the presence of the pathogen which caused it, a host plant and a favourable environment.

He said the research had achieved encouraging results, having identified a number of paddocks in which disease suppression may have been expressed last year - 10 paddocks for rhizoctonia, six for take-all, 11 for crown rot and one for RLN.

“All these paddocks are now being assessed in soil bioassays to confirm disease suppressiveness,” Dr Hüberli said.

He said the potentially disease suppressive paddocks had been identified by comparing the incidence of root disease with DNA levels of the pathogens in the soil before seeding, as determined by the PredictaB test.

“Paddocks which had a high to moderate level of DNA for a disease pathogen, but a low expression of the disease, were deemed potentially disease suppressive,” Dr Hüberli said.

“In the 2011 season, further sites are being screened using this selection criterion.”

Dr Hüberli said the next step of the research aimed to identify the beneficial micro-organisms present in disease suppressive paddocks.

“After we have determined which micro-organisms are present, we want to find out which farm management practices have fostered them,” Dr Hüberli said.

“We will do this by investigating the history of the suppressive paddocks, focussing on rotations, inputs and soil characteristics.”

Using biological suppression to reduce crop losses could improve the profitability of WA growers, who have suffered increasing damage from cereal root diseases and RLN over the past 25 years.

Fungal and nematode root diseases, in wheat alone, currently cost WA growers A$84 million each year.

“If annual wheat crop losses caused by root diseases were reduced by just 3 per cent, and pesticide use was reduced by 5 per cent, the annual benefit to WA growers would be more than A$2.5 million,” Dr Hüberli said.

TheCropSite News Desk

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