TESTING for Root Lesion Nematodes (RLN) during the growing season will help growers plan crop rotations to reduce losses in following years, according to Grains Research and Development Corporation (GRDC) supported researcher Vivien Vanstone.
RLN are microscopic soil pests which feed on crop roots and cause cereal yield losses of about 10 to 30 per cent, although losses as high as 40pc to 75pc have been recorded.
Dr Vanstone, senior nematologist with the Department of Agriculture and Food Western Australia (DAFWA), said growers could not eradicate nematodes – there are no chemicals registered to control nematodes in broadacre crops.
“But growers can reduce nematode numbers in the soil by choosing appropriate rotations and varieties,” she said.
“Growers also need to think about the effect of this year’s crop on next year’s nematode numbers.”
Dr Vanstone said growers should look for signs of nematode problems during the growing season including patchy or uneven crop growth, yellowing and decreased tillering. Symptoms usually begin to appear about two months after the crop is sown.
“It is important to follow sampling guidelines to dig up intact root systems and also include healthy plants for comparison," she said.
“If the laboratory results show there is a nematode problem, growers need to think about using resistant varieties or break crops in the following season to reduce the risk of further nematode damage.”
Dr Vanstone and her team was conducting ongoing GRDC supported research into the management of RLN in WA.
New GRDC funded projects aim to clarify yield losses caused by nematodes in different cereal varieties and determine how different crops affected nematode numbers.
Field trials will be established to quantify yield losses and determine variety tolerance to nematode species in WA.
“This will provide information to help growers choose varieties that have least yield loss under nematode attack,” Dr Vanstone said.
“Varieties that are more resistant will reduce nematode reproduction and minimise the impact of nematodes on crops in following seasons.”
To ensure WA growers receive meaningful information for risk management and rotational decisions, DAFWA is collaborating with the South Australian Research and Development Institute (SARDI) in a national GRDC funded research project.
DAFWA Nematology will assess and provide samples to assist in the calibration and validation of the DNA soil test service (known as PreDicta-B).
The department will also assist in the development of new tests required to ensure RLN risk levels indicated from the PreDicta-B service are accurate for WA farming environments.
Growers can access more information about nematode management from the GRDC’s ‘Plant Parasitic Nematodes Fact Sheet’ available through the GRDC website at www.grdc.com.au/ne matodes_s&w
Nematode information is also available from the DAFWA bulletin ‘Root Lesion and Burrowing Nematodes in WA Cropping Systems’, available through the Bulletins page (accessed through the Publications page) of the DAFWA website www.agric.wa.gov.a u
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