Leifsonia xyli subsp. xyli are words sugarcane farmers worldwide would like to see eradicated; they are the scientific name for the bacterium responsible for ratoon stunting disease (RSD).

Most sugarcane pathologists agree RSD is the most important disease affecting sugarcane (Rott et al.m 2022; Comstock, 2002; Davis & Bailey, 2000; Young & Brumbley, 2004), contributing to yield losses of between five to 60 per cent (www.sugarresearch.com.au; Comstock, 2002).

The bacterium’s potential to wreak havoc is the driving force behind Queensland Cane Agriculture and Renewables (QCAR)’s venture to investigate the latest in technologies to combat the disease.  

Recently this involved a cohort travelling west of cane country to the city of Toowoomba consisting of QCAR CEO Stephen Ryan, Board Chairman and Burdekin farmer Christian Lago, Herbert District Manager Lawrence Di Bella, Board Member and Burdekin farmer Dean Sgroi, and QCAR Herbert Member Michael Penna (also an AgForce Cane Board member).  

The team first visited AgForce’s office to discuss the management of weeds, pests and disease across grain and grazing industries before heading to AgEtal.  

Mr Di Bella, who when not wearing his QCAR boots is a Senior Agricultural Technical Officer and founder of Tropical Agricultural Services (TAS) with decades of research experience behind him, said AgEtal is a privately owned and totally independent agricultural seed, pest and disease testing company.

“It provides a wide range of specialist agricultural support and technical services across Australia,” he said.

“While there we toured AgEtal’s laboratory facilities and reviewed its latest research project that uses LAMP diagnostic methods to screen plants for RSD.”

Mr Di Bella said AgEtal had contracted TAS to undertake the field research component of the project and he would present results from the study at the ASSCT Conference in May.

“The new LAMP method allows farmers and agronomists to easily test sugarcane for infection at a significantly lower cost compared to qPCR methods and results are available within an hour of taking samples,” he said.

“We anticipate the LAMP test, when it is rolled out in coming months, will become a vital tool to managing RSD on farms.”

Next, the QCAR and AgForce crew travelled to the Lockyer Valley to meet with a world-leading expert in RSD and disease diagnostics, Associate Professor Anthony Young, at the University of Queensland in Gatton.

“Dr Young developed the LSB qPCR diagnostic method currently used by industry to detect RSD,” Mr Di Bella said.

“He has a keen interest in the evolutionary relationships that underpin symbioses, particularly those involved in plant diseases, and collaborates with international experts on research looking into how bacteria, fungi, oomycetes and viruses affect a range of plants.”

Mr Di Bella said Dr Young’s research involved building the knowledge base about the epidemiology of plant disease and pests and improving diagnostics and field management.

“He’s also passionate about how biotic factors govern soil health and how we can promote beneficial microbial communities.”

Dr Young spoke to the team about how RSD was spread and novel approaches the industry could take to better manage the disease.

Finally, the team travelled to Brisbane to visit Sugar Research Australia’s (SRA) new labs in Acacia Ridge.

“They’re home to SRA’s tissue culture facilities, biosecurity labs (that include samples of RSD), molecular genetics research and more,” Mr Di Bella said, adding the facility would be adapted in the years to come to enable researchers to drive the sugarcane industry forward.

“Detection is only one method in the management toolkit to combat RSD.

“It is vital to plant disease-free material, practice good crop hygiene, and monitor crops using RSD detection technologies to control the disease.  

“RSD is transmitted by infected propagation material (Steindl, 1950) and then spreads further via cane knives, mechanical harvesters, planting equipment, and poor fallow management hygiene whereby volunteer cane material touches uninfected cane at planting and harvesting.

“It was first found in the Mackay region in 1945 where clear differences in growth were detected in affected and unaffected Q28 planted in the same field (Hughes & Steindl, 1956) but it took decades longer to discover the bacterium behind it (Teakle et al., 1973).

“Across 87,000ha that was monitored for RSD, the annual economic loss was calculated at $25 million (Magarey et al, 2021).

“Dr Young disputes this and calculates the annual losses to exceed $200 million. This doesn’t consider the indirect losses from costs incurred by re-establishing crops removed owing to RSD, increased weed control, and erosion.

“Naturally, the costs promote a desire to implement hygiene and disease management protocols, yet RSD’s lack of external symptoms make it difficult to identify and manage.

“This is why the agricultural industry must investigate novel approaches to better manage the disease, a direction QCAR is pleased to support in our commitment to create sustainable and profitable industry outcomes for our members.”

[ENDS]

For further media assistance contact Media & Communications Manager Heidi Petith, 0427 855 726, [email protected]