FEDERAL biosecurity staff are yet to pinpoint the source of a spreading outbreak of citrus canker first detected in the Northern Territory in April.
Almost two months after the disease was spotted on a potted lime tree at a Darwin nursery, work is still underway to determine the highly contagious disease’s likely origins, the Department of Agriculture statement said is a statement.
The disease is one of Australia’s category two emergency plant pests. An infection causes spongy, eruptive lesions on fruit, leaves and branches of citrus trees.
“At this stage there is no evidence of biosecurity import conditions being a problem,” the Department said, adding it was clear the latest detections were not a re-emergence of a past outbreak.
The bacterial disease last took hold in Emerald, in Queensland, 13 years ago and wiped out thousands of citrus trees. Efforts to rid the region of canker took four years.
Last week the NT Department of Primary Industry and Resources confirmed citrus canker had been detected at a western Katherine property, the seventh in the territory to test positive for the disease.
The infected lime tree was purchased from a Darwin nursery almost a year ago before it was planted on the property.
The latest incursion was unwelcome news for the Nutrano Produce Group, which bought Seven Fields’ Katherine citrus plantation — one of the territory’s biggest — in 2016.
Nutrano’s managing director Steven Chaur said the 60ha citrus orchard was a strategic plantation for the company that let it avoid importing citrus during summer months.
“So when you get a call saying citrus canker has been found you get a bit worried,” Mr Chaur said.
“We moved quickly to put our biosecurity measures in place, restricting traffic to the farm and plant material, and we worked with our staff who have citrus trees at home to make sure there was no risk of contaminating the farm.”
Department of Primary Industry staff have visited the property twice since the latest discovery in Katherine.
More than 2500 sample trees were checked and cleared of the disease.
The Department of Agriculture said the detections were limited to the home and garden sector.
“The affected host plants are potted retail citrus plants destined for people’s garden and patio pots,” it said in a statement. “There is no evidence citrus canker is present in citrus production areas.”
Recent detections in Western Australia have been linked to infected plants from the Northern Territory.
All infected plants found at the site where the disease was first discovered in Darwin have now been destroyed.
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