Durum wheat growers urged to stay ahead of crown rot risk
Author: Sharon Watt | Date: 18 Mar 2015
Growers of durum wheat are being encouraged to test their paddocks for the soil-borne disease crown rot before embarking on this year’s sowing programs.
With prices for durum wheat currently elevated, many growers may be tempted to increase their acreage in 2015.
But before they devise their sowing programs for the coming season, researchers supported by the Grains Research and Development Corporation (GRDC) advise growers to have soils tested to enable pre-selection of paddocks with a low risk of crown rot.
PreDicta B® DNA-based soil testing should be undertaken to assist in identification of crown rot and other soil-borne diseases prior to seeding. Grain producers can access PreDicta B® via agronomists accredited by the SA Research and Development Institute (SARDI) to interpret the results and provide advice on management options to reduce the risk of yield loss.
PreDicta B® samples are processed weekly from February to mid May (less frequently at other times of the year), and SARDI is currently observing a much larger proportion of PreDicta B® paddock samples with medium to high crown rot risk.
Alwyn and Kerryn Dyer, along with their son Jonathan and Alwyn’s brother Eric, run a 2500 hectare broad acre cropping enterprise near Kaniva in Victoria’s western Wimmera. Generally they have a four year cropping rotation which includes durum wheat, canola, bread wheat and pulses (chickpeas, lentils, faba beans, and sometimes lupins).
For several years, with advice from their local consultant Simon Mock of Clovercrest Consulting, Alwyn has been using the PreDicta B® pre-selected low risk paddocks for their durum wheat crops.
The potential yield loss due to crown rot is much greater in durum than bread wheats, so paddocks reported with a medium or high risk are switched to bread wheat, as part of their risk management strategy.
The last two years have been very different. In 2013, four of the 11 paddocks had a medium risk for crown rot, and were sown to bread wheat. The remaining paddocks had either a low risk or were below the detection level, and were sown to durum.
The season was a favourable one, with reasonable sub soil moisture producing consistent durum yields of 4t/ha and 3.5 to 4 t/ha for bread wheats. “Very little to no crown rot was observed in the crops during this year,” Mr Dyer said.
However, 2014 was a very different story. PreDicta B® tests reported much higher risk levels, with several paddocks in the medium and high risk categories. As with the previous year, four medium to high risk paddocks were switched to bread wheat.
“The season suffered a spring drought with no sub soil moisture, and conditions were favourable for crown rot,” Mr Dyer said.
“Higher crown rot levels were observed in all crops that tested medium to high with PreDicta B®, with average durum yields of 1.25 t/ha. Paddocks switched to bread wheat performed better, averaging 2 t/ha.”
Mr Dyer and his family will continue to utilise the PreDicta B® service as part of their risk management strategy. “We find the tests very helpful because these days we seem to get as many dry seasons as good ones. At a cost of less than a tonne of wheat, it’s cheap insurance.”
Consultant Simon Mock encourages his durum growers to use PreDicta B® as a risk management tool.
“I find that the PreDicta B® testing helps to reduce the risk associated with growing durum wheat over bread wheat,” Mr Mock said.
“With current durum prices at a premium over bread wheat we can increase the farmer’s income without increasing their risk. Another added advantage from the testing is gathering information about other important root disease which assists our planning through the rest of the rotation.”
PreDicta B® tests are for most of the soil-borne diseases of cereals and some pulse crops, including crown rot, CCN, rhizoctonia root rot, take-all, Pratylenchus thornei, Pratylenchus neglectus, stem nematode and blackspot.
About 1500 agronomists and consultants across Australia have been PreDicta B® accredited through SARDI’s annual Agronomist Root Disease Risk Management training courses, which are supported by the GRDC.
GRDC Project Code DAS00137, DAS00123
Region South, North