Australia
January 18, 2019

The soil-borne fungi which cause Sclerotinia stem rot have been added to the suite of disease pathogens that can be identified by the PREDICTA® B testing service.

Attending a PREDICTA® B Root Disease Risk Management Course for agronomists in Perth were, from left, CSBP area manager William Tan, of Katanning, Primaries Esperance graduate agronomist Rachel Minett and Elders agronomist Ben McGillivray, of Moora. Photo by GRDC. 
 

Growers can use Sclerotinia data generated from this testing service, in combination with other information, to help determine their overall risk of being impacted by this disease in the coming cropping season.

Stemming from Grains Research and Development Corporation (GRDC) investments, PREDICTA® B is a DNA-based soil testing service provided by the South Australian Research and Development Institute (SARDI) and can test for a comprehensive range of soil-borne pathogens.

Soil-borne disease expert Alan McKay is the leader of the Soil Biology and Molecular Diagnostics group at SARDI, a division of Primary Industries and Regions SA (PIRSA) and was in Perth this summer for a PREDICTA® B Root Disease Risk Management Course for agronomists.

Dr McKay said benefits of the test included identifying pathogens that posed a disease risk before crops were sown and identifying the need for long-term disease management.

“By using PREDICTA® B, combined with advice from an accredited agronomist, disease pathogens can be detected and managed before losses occur from diseases such as Rhizoctonia, Fusarium crown rot and root lesion nematodes, he said.

“PREDICTA® B can now also test for the presence of S. sclerotiorum and S. minor, the two Sclerotinia pathogens most commonly found in WA, although the test does not distinguish between the two species.”

Department of Primary Industries and Regional Development (DPIRD) plant pathologist Geoff Thomas said the development of Sclerotinia in crops was highly dependent on environmental conditions.

“The PREDICTA® B test can add to the information growers have available to them about the risk of Sclerotinia developing in a specific paddock,” he said.

“Growers in high risk situations are advised to implement management strategies, which are available on the DPIRD website”
 

To help assess risk factors for Sclerotinia, growers and their advisers are advised to assess the PREDICTA® B results alongside information about risk factors including:

• Paddock history
• Rotation with susceptible crops
• Disease incidence in the last affected crop
• Distance from last affected crop
• Rain during flowering.

Mr Thomas told the PREDICTA® B Root Disease Risk Management Course that levels of root diseases such as Rhizoctonia root rot and crown rot were generally at ‘normal’ levels in WA in the 2018 cropping season, probably due to seasonal conditions, and this would maintain inoculum carried over into coming seasons.

Growers are encouraged to liaise with an accredited adviser when taking soil samples, interpreting and understanding PREDICTA® B results and developing a plan for variety, rotation and paddock management decisions for next season.

Advisers and growers are urged to include stubble with their samples, as the risk of stubble borne diseases, such as crown rot, is likely to be underestimated if stubble is not added.

The PREDICTA® B service is delivered through SARDI’s Molecular Diagnostic Centre, a state-of-the-art facility capable of delivering high throughput diagnostic testing to industry. Investment in the Molecular Diagnostic Centre and the continued development of PREDICTA® B are components of the GRDC-SARDI strategic research partnership.

For more information on PREDICTA® B, including access to the soil testing service, see here.