Anyway, now I actually realize why USDA is so strict about this
And yet in half the country RIFA is so dominant that it almost wiped out any other ant species (and just wait until the Argentine ants get a foothold in the US which will inevitably happen at some point). So in the end even these regulation did little to preserve the environment - if invasive ants go on global conquest they are an unstoppable force of nature (you could also say they're a creeping natural disaster), regulations or not. In the end we can stop invasive ants as much as we can stop a Tsunami.
And yet Australia has seen successful eradication of RIFA
In Australia, there have been six separate incursions of fire ants. Five recorded in Queensland; and one in Port Botany NSW.
In Queensland, the first two incursions were discovered in 2001, one in the south western suburbs of Brisbane and the other at the Port of Brisbane. The third and fourth incursions were found in Yarwun, Central Queensland in 2006 and 2013. The fifth and most recent incursion to Queensland was found at Brisbane Airport in 2015.
The Port Botany incursion was discovered in 2014 with the NSW Department of Primary Industries leading the eradication response. Biosecurity Queensland provided assistance in the initial response and provides ongoing scientific and operational support when required.
Both the Port of Brisbane and the 2006 Yarwun incursions have been successfully eradicated and the 2013 Yarwun incursion is due to be declared eradicated in July 2016. Spread from the initial Brisbane infestation has led to infestations around the greater Brisbane area including Ipswich, Logan and Redlands. Isolated infestation has also been found in Scenic Rim, Gold Coast and Lockyer Valley.
(DAF, 2016, https://www.daf.qld....sked-questions)