Scientists sniff out biosecurity solution
Citrus canker-seeking canines have successfully completed a trial to detect the destructive disease using synthetic compounds that mimic the scent of plants infected with the disease.
Because of the difficulty in working with the bacteria outside the lab, a synthetic scent was developed for outdoor trials and canine training. The project team believes this could be a first in Australia for plant bacterial diseases.
The Department of Industry, Tourism and Trade partnered with the Australian Government to deliver the $260,000 project, which started in October 2019.
Charles Darwin University (CDU) chemists spent six months in the lab working with the department’s Biosecurity and Animal Welfare project scientist, Alex Fulton. The team collected and analysed volatile organic compound (VOC) emissions, through three sets of experiments including live plants infected with the bacteria, bacterial growth and individually infected leaves.
“These experiments helped scientists develop the chemical composition of the scent blend for the artificial lure used to train the detector dogs,” Ms Fulton said.
Ms Fulton started working with Top End Conservation Dogs trainer and handler Bronwyn Mullins on the trials with a kelpie cross cattle dog and two kelpie cross beagles in April 2021.
“Detector dogs can potentially discover the disease earlier than humans, including before the symptoms are visible, and also search larger areas like orchards,” Ms Fulton said.
“Over the five week training period, the dogs were able to identify and locate the scent in different scenarios and outdoor locations, with a variety of distractions.
“The exercises made sure the dogs were identifying the scent and not responding to behavioural cues, or a human scent trail. Part of the trial also involved searching in a retail nursery to mimic how the dogs would work in this environment,” she said.
“While the percentage success rate is still to be assessed, anecdotal observations are that the dogs have a very high success rate for detecting the lures.”
This project is building the Northern Territory’s (NT) capacity to deal with citrus canker (Xanthomonas citri subsp. citri), as well as other plant pests and diseases. It also provides the NT with a local option for the rapid deployment of dogs for plant biosecurity eradication programs in the future.
The department’s Chief Plant Health Officer, Dr Anne Walters, said the work with CDU chemists had laid the groundwork for future artificial lure detection projects.
“The focus on local expertise and solutions are important when protecting a multimillion dollar industry,” Dr Walters said.
“The knowledge gained from this project could be put to use in the future, detecting other biosecurity threats in the Northern Territory and helping the NT to respond rapidly to pests and diseases when they are detected.”