For decades, South Australia claimed the title of being the only mainland state free of fruit fly — but that prized status came under serious threat just over a year ago.
While vast tracts of metropolitan Adelaide are now caught up in a series of outbreaks, it is the spread of the pest in the Riverland region which has growers on tenterhooks.
Extensive eradication efforts are currently underway, and authorities are confident the outbreaks will eventually be brought under control.
But some producers are concerned it might already be too late.
"If growers were on the brink of not being viable to start with, this is going to have a huge impact and those growers may not even continue," said Riverland stone fruit orchard operator Jason Size.
There are currently 10 outbreaks of Mediterranean fruit fly in metropolitan Adelaide, with the first detection in Blair Athol in December, 2019.
Queensland fruit fly has also been found in Ridleyton, in Adelaide's south, alongside five different areas in the Riverland, where eradication efforts have accelerated in recent weeks.
Biosecurity SA executive director Nathan Rhodes said the collective outbreak of the pest was one of the biggest the state has seen, and battling two different species at the same time has been a significant challenge.
"The responses are really labour intensive — it takes a lot of people knocking on people's doors and going into backyards," he said.
"There's in the vicinity of 150,000 households that are affected in Adelaide alone.
"Likewise, you go to the Riverland — we have a lot of residential properties in that area, but also commercial properties, that are growing and trying to move fruit that need to have treatments applied or conditions put in place to allow them to continue to operate."
In Adelaide, the so-called "orange army" of the Department of Primary Industries and Regions (PIRSA) is out in force, knocking on doors and inspecting and treating plants in the worst-hit suburbs.
Millions of sterile fruit flies are being released in the Riverland every week, and Mr Rhodes described the containment methods being used as "tried and true".
"We've used them over and over again — they are internationally best-practice methods that are used around the world to eradicate fruit fly from areas where it's not endemic," he said.
Backyard growers also feeling the impact
Restrictions on the movement of some fruit and vegetables in the outbreak zones are set to be in place until around the end of the year.
But the impact is not just on large-scale or commercial growers.
For about a decade, Monica O'Wheel has run a community market in Payneham, in Adelaide's east, which heavily relies on home-grown fruit and vegetables.
Ms O'Wheel said the restrictions mean the market is "limping along".
"It's hard for people individually, I think, but we also want the outbreak to stop because we don't want fruit fly here," she said.
"People when they have a fruit tree that bears a lot of fruit — there's no way they can eat it all themselves, even with preserving and drying."
Ms O'Wheel said while the outbreaks have been frustrating, everyone needed to play their part in making sure people understand the movement restrictions.
"When I went to my yoga, I said to someone who brought in lemons to share … 'You can't do it, you just can't'," she said.
Despite the situation, South Australia remains the only mainland state classed as fruit fly-free — but that status has been suspended in the outbreak zones.
PIRSA said it had communicated with interstate trading partners to assure them that the outbreaks are being handled.
"If we're not successful in eradicating the current outbreaks, then we will have problems with our fruit fly-free status," Mr Rhodes said.
"While we're under an active eradication, we excise [outbreak areas] from our pest-free status and the rest of the state remains acknowledged to be pest-free."
South Australia's horticultural industry is a significant economic contributor — in 2018-19, it generated $1.7 billion in overall industry revenue.
Mr Size said increased costs and extra procedures put in place to mop up the outbreak have already been "devastating" for growers.
"With the labour shortage we've had this year, the fruit fly treatments that growers have had to undertake has probably caused quite a bit of a financial burden," he said.
"[There's been] a lot of uncertainty and heartache to just try to work out what to do to move their fruit."
Photo: PIRSA has deployed staff to curb the outbreaks (Source: ABC News, Mahalia Carter).
Acknowledgement: this article was reproduced from a media release by Abc News.