Researchers at Sugar Research Australia (SRA) have made a major breakthrough in determining the cause of a sugarcane disease that has remained a mystery for 87 years.
Chlorotic Streak Disease (CSD) was first recognised in 1929, and since then there has been research effort from around the world to determine the cause of the disease, how it is spread, and how to manage it.
In a major breakthrough, SRA researchers Dr Kathy Braithwaite, Dr Chuong Ngo and Mr Barry Croft have recently used modern DNA technology and traditional pathology to identify a new type of organism that causes CSD, isolating a microscopic organism that is a type of protozoan.
CSD is a serious and widespread disease of sugarcane. In the worst cases, yield losses can be as much as 40 percent and it has been estimated to cause an annual loss to the sugarcane industry of $8 million to $10 million. Because it is transmitted via water, its impact is worst in wet growing districts of the Australian industry.
SRA Biosecurity Manager, Mr Barry Croft, said it was an important discovery for the Australian sugarcane industry.
“Understanding the cause of a disease is crucial to developing control and management strategies for that disease,” Mr Croft said. “By SRA identifying the protozoan that causes CSD, we hope this leads to better management options and information, which will lead to benefits for sugarcane growers and millers.
“For example, SRA already gives all of its varieties a rating for resistance to diseases, including CSD. That information is crucial for growers when they choose what variety to plant according to the conditions on their farm. The discovery of this organism has opened up more reliable ways to screen the varieties for resistance to CSD.”
SRA has also developed a technique to diagnose whether sugarcane is infected with CSD, and is working with productivity service organisations to ensure this technique is useful and practical. “Because CSD can spread so easily, proper use of a diagnostic test for CSD could reduce the spread of CSD via planting material, for example,” said Mr Croft.
“Now that we know what the organism is, we also may be able to develop more targeted control methods.”
Sugarcane grower Mr Ray Zamora’s farms are in one of the highest rainfall areas of the Australian sugarcane industry at Tully, meaning he has faced significant yield losses from CSD in the past when there have been particularly wet years.
He welcomed the news that SRA researchers had discovered the organism that causes CSD.
“Managing CSD is something that I could change on my farm if there was improved information. If I had better resistance information for sugarcane varieties I could avoid planting susceptible varieties in the low lying parts of my farm, so this discovery is welcome news,” Mr Zamora said.
This research activity has been jointly funded by SRA and the Queensland Department of Agriculture and Fisheries