PIRSA Food and Plant Standards manager Geoff Raven, said that during the blitz, 629 vehicles were stopped on the Dukes Highway near Bordertown with 12.71 per cent of vehicles carrying fruit and vegetables in violation of quarantine restrictions.

“This is a significant decrease in comparison with some of the previous operations on the same highway, where closer to 20pc of vehicles were carrying fruit and vegetables into the State,” he said.

About 80 expiation notices were issued, with fines ranging from $55 to $210, depending on how much fruit was being carried.

“The main offenders were Victorians with 50 expiations issued, but the worrying statistic is that 25 South Australians coming home copped a fine,” Mr Raven said.

“They have chosen to ignore the prominent signs at the border and not stopped at a disposal bin. More importantly, they have put the State at risk.

“Just one infected piece of fruit can spark a fruit fly outbreak and that isn’t needed when growers are battling drought. We can also enjoy our backyard fruit trees without the threat of fruit fly.

“We are particularly concerned with the threat to SA this year, given the large number of outbreaks in Victoria. Five seizures during the random roadblock involved backyard produce from Victoria.

“This produce has been secured for a period of time and will then be checked for any fruit fly larvae.”

Mr Raven urged people to not travel with fruit and vegetables into SA.

“It is vital that we maintain our status as the only mainland state that is fruit fly free,” he said.

Further random road blocks will be mounted around the State in the lead up to the fruit fly season, and during the school holidays.