Efforts to protect the Riverland from Mediterranean fruit fly have strengthened, following three outbreaks of the pest in metropolitan Adelaide during recent months.

With the Riverland recognised as a fruit fly-free zone by export markets like Taiwan, Japan and the United States – the rest of SA is recognised as fruit fly-free for domestic purposes only – Biosecurity SA Plant Health Operations Group manager Nick Secomb said extra roadblocks had been implemented.

“We have a random roadblock program which we can tinker with and move depending on risk,” he said. “Since we had the outbreaks declared, they've concentrated on making sure that any metropolitan traffic into the Riverland is checked to make sure we don't take any problems there.”

Secomb said the random roadblock team, which sporadically set up at Bordertown to check interstate traffic, had supported PIRSA's permanent measures to monitor the threat of fruit fly. “We have more than 3000 traps across the state that monitor things so we're really confident that the rest of the state is clean.”

Member for Chaffey, Tim Whetstone, said SA and the Riverland should be on ‘high alert’, especially given fruit fly could affect $1.1 billion of SA’s horticultural produce. “It only takes one person to do the wrong thing and bring a piece of fruit or vegetable containing fruit fly larvae in for it to have a devastating impact.”

Under national protocol, PIRSA enforced 1.5-kilometre quarantine zones surrounding the outbreaks in Colonel Light Gardens, Highgate and Clarence Park. The Clarence Park zone was extended after three male Med flies were found in Camden Park late last month.

“We put out more than two million flies a week for four weeks so anything that escaped the bait will be overwhelmed by these sterile flies and not be able to breed,” Secomb said.

PIRSA has also started work on a $3.8m facility in Port Augusta, which will deliver 50m sterile male Qld fruit flies a week.