Fire ants not only damage our lawns with their unattractive dirt mounds, but they can also pose a health threat to people and pets with their venomous stings. Completely ridding your lawn of this red menace forever may be an unrealistic expectation, but it is possible to keep the population in check with regular treatment.
Identifying Fire Ants
The tiny reddish–brown ants were unintentionally imported from Brazil, and because they have no natural predators in the U.S., they thrive in great numbers from coast to coast, mainly across the southern tier of states. Lawn infestations are easily identified by the large dirt mounds, usually found in sunny areas. The mounds can reach 7 inches high and 24 inches across or more. Under the mounds, the ant colony digs extensive tunnels that often stretch beneath several lawns, housing up to half a million ants with multiple queens.
When a mound is disturbed, ants aggressively swarm from the nest to attack intruders. A single ant can sting several times, grabbing the victim with its jaws and then pivoting in a circle. Although the ants range from only 1/16” to 1/5” long, their stings pack a serious punch, causing a burning sensation followed by extremely itchy red bumps and blisters. Some people, and even pets, may experience more severe allergic reactions, from localized swelling to life-threatening anaphylaxis.
Because the ant colonies thrive in such astonishing numbers underground, wiping them out entirely is nearly impossible. The most effective method for control is to hire a professional landscaper or pest control company to eradicate the mounds.
If you decide to take on the ants yourself, start with a broadcast bait. Many brands are readily available at home improvement centers. Spread the bait in a four-foot radius on and around the mound, being careful not to disturb the mound in the process. The ants will take the bait underground to their friends and queen, killing all who eat it.
Fire ants are very sensitive to smell, so avoid using a spreader that’s been used for fertilizer. Even smells like cigarette smoke or gasoline transferred from your hands or gloves to the bait will cause the ants to refuse it.
Wait a week to ten days, and with a long stick, prod the mound and watch—from a safe distance—for ant activity. If no ants respond, carefully knock down the mound and spread a bit of compost on the area to encourage the surrounding grass to fill in the bare spot.
However, if you see ants, a second treatment is in order. This time you’ll need a gallon or two of premixed liquid insecticide. Push a long stick down into the center of the mound. Quickly pull the stick out and immediately pour insecticide into the mound, filling the tunnels underground. The insecticide will kill the ants on contact, but be careful—they move surprisingly fast. Always wear protective clothing and stand as far back from the mound as possible while you work.
Although you or the pros may have eradicated the mounds for now, ants from nearby tunnels or neighboring yards will likely infiltrate again. In order to keep the fire ant population at bay, you’ll need to inspect your lawn in the fall for activity and treat any infested areas with broadcast bait. Treating each spring and fall should keep the red pests in check so you can safely enjoy barefoot walks through your grass.