Imported fire ants came to the U.S. from South America in the 1930s. They entered at Mobile, Alabama, probably in soil used for ship ballast.
With no predators, they spread quickly. They occupy millions of acres throughout the Southeast, Texas, and irrigated spots in the Southwest, says Bart Drees, the coordinator of the Texas Fire Ant Project. The ants have been seen in Delaware, Virginia, Tennessee, Oklahoma, and Nevada, and now they're in Orange County, California. Because of the mild climate, irrigation, and other water sources, the entire Pacific Coast is fertile ground for infestation, says Drees.
Fire ants can be found in urban areas, especially when water is available. Fire ants are effective predators and can feed on many other insects (harmful and beneficial types). Evidently, they won't stay in areas where it gets down to 10 degrees F in winter, but they can overwinter in heat sources such as electrical boxes, laundry outlets, and outbuildings. For more information, visit http://fireant.tamu.edu.
If stung, dab the bite with ammonia or a 1:1 solution of bleach and water within 15 minutes to neutralize the protein in the venom. Otherwise, apply a sting remedy with benzocaine or other pain killers. Don't scratch or a nasty secondary infection may result. Some people are allergic to fire ant stings and should seek medical attention immediately.