Root lesion nematodes (RLN) are proving to be at high levels in Western Australian cropping paddocks this year and growers are encouraged to have samples tested to help them manage the pest in coming seasons.
Surveys conducted by the Department of Agriculture and Food (DAFWA), with support from the Grains Research and Development Corporation (GRDC), showed that RLN caused widespread damage in every WA cropping zone last year.
“RLN species were found in 90 per cent of 130 paddocks surveyed, and in 48 per cent of paddocks the nematode levels were high enough to cause 15 to 50 per cent yield loss,” DAFWA researcher Sarah Collins said.
“Pratylenchus neglectus and P. teres – the major RLN species affecting WA broadacre crops - were found in 68 and 24 per cent of paddocks respectively.
“RLN, as well as root diseases, are prevalent again this season and testing is already showing elevated nematode levels in paddocks.”
Dr Collins said tell-tale signs of RLN included patches or uneven waves of crop growth in paddocks, yellowing and reduced tillering.
She encouraged growers who suspected the presence of RLN in their paddocks to contact her (firstname.lastname@example.org) and to send samples to AGWEST Plant Laboratories for confirmation and species identification.
Information about this service is available on the DAFWA website, under AGWEST Plant Laboratories (www.agric.wa.gov.au/n/1801).
“Correct diagnosis will help growers plan rotations to assist in the management of RLN,” Dr Collins said.
“Resistance ratings for the most common RLN species are available in WA’s crop variety guides available via the DAFWA website (www.agric.wa.gov.au/n/2426) or GRDC website www.grdc.com.au.
“If RLN levels in a paddock are high to very high, DAFWA recommends growing a moderately resistant (MR) or resistant (R) crop or pasture for one to two cropping seasons.
“There are no chemicals currently available to economically control nematodes in broadacre cropping systems.”
Dr Collins said correct RLN diagnosis would also assist in characterising nematode distribution and gathering further resistance information for crop types and varieties in WA.
The DAFWA research is supported by a national GRDC funded nematode program quantifying the yield and economic impacts of RLN and refining management options for the pests.
More information about the research into nematodes, as well as root and crown diseases, is contained in a GRDC Root and Crown Diseases Supplement available in the July-August edition of Ground Cover magazine and at www.grdc.com.au/GCS111.
This supplement reports on a suite of new national GRDC programs which are launching a fresh attack on root and crown diseases and nematodes, which collectively cost Australian growers hundreds of millions of dollars in lost production and control costs each year.
To subscribe to Ground Cover visit www.grdc.com.au/groundcover.
Information about nematodes is also contained in a GRDC GroundCover TV video available at www.grdc.com.au/GCTV6-RootLesionNematode.
Caption: DAFWA researcher Sarah Collins says testing will help growers plan rotations to assist in the management of RLN.
Sarah Collins, DAFWA
08 9368 3612, 0404 488 113
Natalie Lee, Cox Inall Communications
08 9864 2034, 0427 189 827
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