13 February 2014
Many South Australians might not be aware that when the threat of fruit fly looms for local crops, the South Australian Museum’s Senior Research Scientist in the Evolutionary Biology Unit, Mark Adams, is the man who tests for the pests.
At our North Terrace laboratories behind the Museum galleries, Mr Adams conducts up to 20 fruit fly tests each year for the Department of Primary Industries and Regions SA (PIRSA). He has tested for the dangerous pests in recent scares or outbreaks, including at Sellicks Beach and in the Riverland.
Mr Adams uses genetic technology to provide results after only three hours, which is crucial in helping the State Government swiftly respond to the pest.
“I receive the call as soon as they have found maggots, and I have a sample dropped off to me here at the Museum. I fish out the maggots, rinse them, crush them up in a simple buffer and load them on to my gels and run a process called protein electrophoresis.”
There are newer DNA tests to identify a species, but they are much more time consuming than protein electrophoresis, and can quickly work out how many species there are in a group of animals.
“Using DNA sequencing for a standard gene will typically take a day or two and it might always not tell you what species it is. In the case of fruit fly outbreaks, it’s that rapid response that allows you to control them successfully.
“A day or two’s delay in hot weather will mean that some of the maggots will hatch to adults and then some of those adults will go out and the adults are quite mobile so suddenly the outbreak isn’t contained.”
Before these rapid genetic tests became available, maggots could only be identified once they had completed their life cycle and turned into adults, by which time the outbreak might already be days old.
Usually, PIRSA will run an eradication program including hygiene (removing fruit from suspected trees, fallen fruit from the ground and using deep burial), bait spotting with organic spray and setting up an intensive network of fruit fly traps in the quarantine area. PIRSA releases sterile adult males as an option towards the end of the eradication program, to ensure that the process over a 12- week period has been successful.
Mr Adams is one of the Museum’s longest-serving researchers and has been testing for PIRSA for many years.
“In these tests I use reference material we have in the freezers to see if the maggots could be the most common pests – the Mediterranean and the Queensland fruit flies.
“We are the only mainland state that is fruit fly-free, which is worth a lot of money for export.”
Mr Adams has conducted testing for recent suspected fruit fly outbreaks.
Information on current outbreaks being managed in the Riverland and Sellicks Beach areas can be found on the PIRSA website.