Solution: RAID in the red can! They don't stand a chance all bundled up like that floating,  perfect kill zone to eliminate a colony in seconds.

http://didyouknowfacts.com/fire-ants-surviving-houston-floods-making-terrifying-rafts-bodies/?utm_source=Web&utm_medium=Partner&utm_campaign=AOLHP&utm_term=pubexchange-did_you_know-aol

The solution:

One of these could probably eliminate 20 flotillas!!!!!!  It amazes me people are so freaked out about these little <snip>s,  we used to annihilate them in our yard when we lived in Georgia using a Bobcat with a bucket and a petroleum based octane rated combustible accelerant.