A kiwi fruit orchard near Shepparton is the site of a biosecurity scare, with Agriculture Victoria plant health officers investigating after a suspected detection of the vine-killing bacterial disease known as PSA.
Results are expected by the end of the week, with the investigation being carried out at the Seeka Australia orchard at Bunbartha.
The New Zealand-owned company has removed four-and-a-half hectares of kiwi fruit vines as a precautionary containment zone.
Seeka chief executive Michael Franks said the plants in question were in a new section of the property trialling red and gold varieties of kiwi fruit, which are known to be more susceptible to Pseudomonas syringae pv. actinidiae, or PSA.
“We have 154 hectares of kiwi fruit in Australia, 93 of which is green and mature,” Mr Franks said.
“Our new variety blocks are under constant monitoring and we’re working with Agriculture Victoria to ascertain what we’ve got there.
“The primary symptom is a canker, either a red ooze or clear canker coming out of the vine.”
Plants grafted in Australia
Seeka released information about the suspected detection to shareholders in New Zealand in early October.
Mr Franks said it was important to differentiate a biosecurity scare with food or product health.
He rejected the possibility of PSA contamination coming from New Zealand, which has battled the disease for more than eight years.
“All of the plants we’ve grafted in Australia were already in Australia,” Mr Franks said.
“We’ve been very careful with our own hygiene protocols so we don’t cross-contaminate.
“It’s a plant health issue, not a food or product issue. In no way is the fruit from the orchards unsafe. It’s safe.”
Victoria has three of Australia’s six large kiwi fruit orchards.
‘Appropriate measures being taken’
Agriculture Victoria has taken samples for bacterial testing and is working closely with New Zealand authorities and the affected business.
Chief plant health officer Rosa Crnov said she was comfortable the appropriate measures were being taken to contain the suspected outbreak.
“Any susceptible vines are being destroyed and burnt,” she said.
“The worst case scenario is the aggressive form can get into vines and kill them.”
Dr Crnov said there was a mild and aggressive form of PSA and “dark spotting” was a strong indication of the disease.
She said PSA, which is specific to kiwi fruit, was typically spread during the propagation process or by wind after heavy rain.
“The best time to see symptoms is spring, which is probably why we’ve had this suspected detection now,” she said.
“The good news is PSA does not like the hot summer weather so we’d be pretty confident, regardless of what type of PSA we have, that it will be dying out over the summer months.”
Dr Crnov echoed Mr Franks’s assessment of the investigation.
“This is not a food safety or human health issue, it’s a biosecurity issue,” she said.