Tasmania on alert as fruit fly outbreak threatens $50m industry

Tasmania’s $50m stone fruit export market is under threat from a fruit fly outbreak, in which more than 60km of the northern coast has been placed under quarantine.

Authorities on Wednesday issued a state-wide alert for the pest, which had been detected in produce certified as fruit-fly free and prepared for sale at a supermarket in Devonport.

Produce from that supplier has been recalled from retailers, and Tasmanians have been told to double-wrap all fruit and vegetable waste to be placed in the rubbish bin, rather than the compost, to prevent further outbreaks.

Larvae of the Queensland fruit fly was detected in apricots in three backyard orchards on Flinders Island and one in Spreyton, a small town on the Tasmanian mainland near Devonport, in January.

On Tuesday, the Department of Primary Industries, Parks, Water and Environment (DIPIPWE) confirmed that five adult fruit flies, as well as larvae, had been detected in another backyard orchard in George Town, which is 40km east as the crow flies from Spreyton and 30km outside the existing control zone.

Control zones are established in a 15km radius around confirmed fruit fly sightings.

Since the outbreak was confirmed, authorities have received more than 330 reports of potential fruit flies and trapped more than 23 adult flies.

The state’s agriculture minister, Jeremy Rockliff, said the supermarket discovery provided a “clearer idea” of how the pest may have evaded the state’s biosecurity protections.

The Hodgman government — which is currently vying for re-election — said it would give Biosecurity Tasmania “a blank cheque to respond to this issue as they see fit”.

“It now appears that there may have been a failure in the fruit fly-free certification process on the mainland, rather than an issue with processes in Tasmania,” Rockliff said.

Taiwan suspended fruit imports from Tasmania earlier this month, prompting concerns that other Asian countries, which are particularly sensitive to fruit fly incursions and which make up about 75% of the state’s fruit export market, could follow suit.

The island state’s agricultural export market, which along with forestry and fishing makes up 9% of its gross state product, is heavily reliant on its pest-free status.

Anything that threatens that status could have dire economic consequences, said Prof Anthony Clarke, a leading Australian expert on fruit flies and biosecurity at Queensland University of Technology.

“Tasmanian trade is based on the fact that they don’t have fruit flies,” Clarke said. “The suggestion that it could be there is very damaging for negotiating new markets.”

Fruit flies have not historically survived the Tasmanian winter, but the state government’s fruit fly strategy warns that risk profile is changing with climate change.

Queensland fruit fly primarily affect stone fruit, including cherries, the eighth most valuable agricultural export in 2015-16, with a gross value of $64m.

Clarke was “pretty confident” the incursion would be controlled, saying it was “a big enough scare” to encourage the state to tighten up its biosecurity controls, including a network of 1,400 insect traps, which are placed 5km apart at key entry points to the state.