Variety trials in Queensland have demonstrated that an ounce of tolerance is worth a tonne (or more) in extra yield when it comes to dealing with root lesion nematode (RLN).
Root lesion nematodes (Pratylenchus species) occur in cropping paddocks in South Australia and Victoria as well as the northern wheat belt. Pratylenchus can cause significant yield losses, which may be as high as 40 per cent.
Pratylenchus has a much wider host range than cereal cyst nematode (CCN), including wheat, barley, oats and chickpeas, as well as pastures (medics and subclover). Wheat-chickpea rotations are particularly susceptible, although resistance can vary in individual varieties.
"Where soil nitrogen is not limiting but nematodes are present, wheat varieties like Sunvale and Pelsart can show gross margins of up to three times those of intolerant varieties and double those of barley," said John Thompson, principal soil microbiologist and leader of the Queensland Wheat Research Institute's (QWRFs) RLN research team.
The table below shows what he means. Given the dollars at stake, Dr Thompson urged growers to test their paddocks for nematodes before the winter planting season.
Dr Thompson said QWRI would conduct a laboratory analysis of soil samples collected by farmers and determine the nematode status of any paddock at a cost of $90 a paddock.
He said growers could obtain submission forms for the required details of paddock history from QWRI as well as detailed instructions for soil collection.
Pratylenchus symptoms may not be pronounced, and can be confused with other crop maladies.
Program 1.6.1 Contact: Dr John Thompson 07 4639 8888
In SA, the soil assay test is available from Alan McKay, SARDI Plant Pathology Unit, 08 303 9375. In Victoria, it is available through VIDA, Horsham, Grant Hollaway, 03 5362 2111. A fee is charged for each sample assessed.
The soil test is not available in NSW, but northern NSW farmers could send samples to QWRI for testing.
1996 Tolerance Trail
|Cultivar||Grain Yield (kg/ha)||Grain Protein %||Gross Return ($/ha)|