Farm Management

Survey highlights impact of soil borne disease risk on crop yields

DPIRD regional research agronomist Kylie Chambers has reminded grain growers of the importance of managing soil borne disease risks, after a recent survey of the eastern Grainbelt. Image courtesy of WA DPIRD

The importance of effectively identifying and managing soil borne disease risks in the eastern Grainbelt of Western Australia to optimise crop potential has been highlighted by a recent paddock survey.

The pre-sowing survey conducted by WA Department of Primary Industries and Regional Development in 2017, supported by the Grains Research and Development Corporation (GRDC) and Agriculture Victoria, found more than 99 per cent of paddocks had one or more disease pathogens present.

The survey results were discussed at the recent 2018 GRDC Grains Research Updates, where crown rot, rhizoctonia root rot and root lesion nematode were identified as the most commonly detected disease pathogens in the eastern Grainbelt.

A total of 136 soil samples from 128 cropping paddocks in the survey area were assessed using the PREDICTA B® soil test.

Department regional research agronomist Kylie Chambers said while the testing identified the presence of these pathogens and indicated potential disease risk, there were other significant factors that influenced the extent to which diseases developed.

“Testing showed 79 per cent of samples had root lesion nematodes, 62 per cent had crown rot and 49 per cent had rhizoctonia, with 99 per cent of paddocks having one or more of these or other pathogens present,” Ms Chambers said.

“While these pre-sowing results showed the risk of disease, seasonal conditions – particularly rainfall – the choice of crop and variety and paddock management practices are key determinants to how the disease develops and its impact on crop yields.”

The incidence and impact of soil borne diseases are highlighted by the results of GRDC’s National Focus Paddock survey, led by the Birchip Cropping Group and the CSIRO in 2015 and 2016.

The national survey showed root disease in cereal crops in Western Australian northern, southern and western cropping zones could have resulted in yield losses as high as 20 per cent in 2015 and 40 per cent in 2016.

Ms Chambers urged growers in the eastern Grainbelt to plan their 2018 cropping program carefully to minimise the development of soil borne diseases.

“While non-cereal break crops are an effective means of managing the risk of soil borne diseases, profitable options are fairly limited in the eastern Grainbelt,” she said.

“It’s important to use other timely strategies, such as selecting crops and varieties with disease resistance, employing sowing times to minimise the risk of moisture or heat stress during grain fill, inter-row sowing to limit contact with inoculum and good crop nutrition to support root development.”

For more information on grain crop disease management and forecasts, visit the department’s website and search for ‘crop diseases’.

Source: WA DPIRD

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