Despite being tiny in size, Red Imported Fire Ants carry a big sting.

Despite being tiny in size, Red Imported Fire Ants carry a big sting.
Image Credit: Tim Davis / Clemson University

CLEMSON — A barefoot frolic through your yard on a warm spring day can change from joyful to agonizing in a flash with just one wrong step onto a fire ant nest.

While you’re standing there enjoying the breeze, the tiny but vicious insect predators will be climbing up your leg, which they’re viewing as a gigantic threat to their survival, and preparing to attack.

The first sting will set off a barrage of others.

Fire ants bite your skin with their mandibles, hang on tight, and then jam the stingers on their abdomens into your flesh. (See an animated video here.) The site of the sting hurts — a lot — for several minutes. It then swells into a bump that eventually turns into a pustule that can last for days, sometimes becoming infected and requiring further treatment. The venom can lead to severe allergic reactions in some people, occasionally resulting in death.

Throughout the Southeast, as well as Texas and even parts of southern California, fire ants are annoyingly plentiful. And they’re not going away any time soon.

“There’s no silver bullet out there,” said Tim Davis, a Clemson University senior Extension agent based in Richland County. “There’s no eradication program for fire ants that has worked anywhere in the world. In the United States, they inhabit about 325 million acres. The majority of the country — whether too cold, too dry or both — does not have fire ants, but there are a lot of people in the areas where fire ants do thrive.”

South Carolina is a haven for fire ants, especially in open and disturbed habitats. Where tree canopy cover exceeds 60 percent, they typically are not present.

With summer-like temperatures already baking the ground, this is the time of year fire ants become active again, wreaking havoc not just in yards, but also in gardens, pastures and farmlands. In addition to stinging humans, they prey on beneficial insects, worms, bird eggs and even small mammals.

“Fire ants are voracious predators,” Davis said. “They will also tend aphids, herding them like cows. They’ll prey on newly hatched chicks. They’ll out-compete birds for their food sources, forcing the birds to forage farther for food, which exposes them to other predators. These kinds of impacts are hard to quantify, but they are probably a larger issue, ecologically, than just the human health issue.”

About the only good news is that controlling fire ant populations is relatively simple, if you follow proper procedures. Many fire ant baits recommend spreading the product around the mound, but Davis said that for every mound you can see, there might be a dozen you can’t. Therefore, he recommends broadcasting the bait over your entire yard with a hand seeder while being careful to avoid sensitive areas, such as ponds and gardens.

“We recommend that homeowners use about a pound to a pound-and-a-half per acre,” Davis said. “This allows the ants to pick up the bait and bring it back to their colonies where it will kill the queen and the rest.

“But the key to success is to do this while the ants are foraging. So first you should put out test bait, like a little piece of hot dog, and then wait 20 to 30 minutes. If you see ants on the hot dog, then it’s the perfect time to put bait on your yard. If you don’t see ants, then you’ll most likely be wasting time and money, because the baits contain oils that go rancid relatively quickly, and once they’ve lain on your yard for awhile and gone bad, the ants won’t be interested.”

Davis said following this procedure will usually kill between 85 and 95 percent of the fire ants in your yard. If you have mounds that continue to be a problem, then you can do individual mound treatments after that.

Less than a century ago, there were no imported fire ants in the United States. But since that time, red imported fire ants and black imported fire ants have been unintentionally brought into the country from their native South America via soil used as ballast in cargo vessels.

Fire ants live in colonies in the soil, and the mound you see above ground represents just a portion of the entire nest. The intricate web of tunnels below ground is extensive, including foraging tunnels that can extend dozens of yards from the main colony. The foragers use these tunnels — as opposed to holes in the mound itself — to enter and exit the nest.

Test baits such as oily slices of hot dogs will help homeowners determine if fire ants are foraging.

Test baits such as oily slices of hot dogs will help homeowners determine if fire ants are foraging.
Image Credit: Jim Melvin / Clemson University

Fire ants form new colonies when winged males and females soar hundreds of feet into the air and mate while in flight. The males die soon after, but the females land and then go in search of a place to start a new home. There will always be new queens looking for fresh starts, and they can re-infest from long distances. This makes it virtually impossible to eradicate fire ants permanently from your yard.

Fire ants cannot eat solid food, so they carry it back to the nest and feed it to the oldest larvae, which are able to externally digest solids and turn them into nutritious liquids. The worker ants then share this now-edible byproduct with the queen and the rest of the colony.

“I tell people, ‘The only way to get away from fire ants entirely is to move up North,’ ” Davis said. “But with the technologies now available, the problems they create in your yard can be minimized with regular treatments.”

For more videos on treating your yard for fire ants, click here and here.