The red imported fire ant, Solenopsis invicta, is one of the world’s most dangerous invasive ant species with a painful sting and venom.
Control fire imported ants in the yard and garden!
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Get rid of fire ants fast with proven methods! Fire ants are a growing problem in Southern yards and gardens, posing risks to people, pets, and even some crops. Discover how to kill fire ants immediately and protect your outdoor space.
Where Do Fire Ants Live?
Fire ants live in the South, but not so much farther north. Many types of ants are called fire ants, but the ones we run afoul of are a few invasive species commonly called red imported fire ants, but there are also black imported fire ants. They’re from South America, hitched a ride on cargo ships years ago, and belong to the genus Solenopsis. The red fire ants are Solenopsis invicta Buren, and the black fire ants are S. richteri Forel. See this map for where fire ants have been found.
Fire Ant Bites
While we commonly talk about fire ants “biting,” which they do, that isn’t what causes the pain. Fire ants will grab your skin with their mandibles, but they’re so small that this rarely hurts. They grab on with their mouthparts to hang on to us and then stab us with a needle-like stinger and inject venom. That’s where the pain comes, and what causes the itching and pustules to form. For most people, it’s a painful, small wound on the skin to be treated like other minor injuries, but a few people have an extreme allergic reaction and may need medical treatment immediately.
How to Identify Fire Ants
Red imported fire ants are small, so that’s a start. If you see a half-inch-long ant, it’s not a fire ant (not one we’re concerned with here in the US, anyway). These fire ant workers are ⅛ to ¼ inch long, with reddish brown and black bodies. They also have a ten-segmented antenna, but you’re probably not going to count that!
Their mounds are usually in open areas, quite noticeable, and can be home to a couple of hundred thousand ants. Sometimes, mounds seem to disappear in hot, dry weather as the ants head deeper, only to reappear again after a heavy rain. If you live in an area where fire ants exist, find a large mound (they can be up to 18 inches high) in an open area, near a downed log, or in the garden, and see tiny reddish brown ants scurrying about, it’s time to be cautious.
Identifying Fire Ant Damage
In the garden, fire ants can attack young plants, bore into potatoes, and be a problem in okra, where they feed on developing flower buds. They forage widely from their nest and like to grab oily or greasy food items. If you see an ant mound, look at it closely and watch the comings and goings. Unlike many other ant mounds, fire ant mounds don’t have a central opening for all that ant traffic.
What to Do if Fire Ants Get on You
While alarming, fire ants don’t usually sting the first second they touch skin. Here are a few tips if you notice you’ve disturbed a mound (gardening, standing on a mound, or otherwise riling it up).
- Brush them off your skin with a fast motion.
- Don’t try to shake them off or rinse them off.
- If they’ve gotten under your clothes and are stinging you, strip down (all the way), shake out your clothing, and carefully inspect every last inch for ants.
- Ice or pain-killing topical ointments and sprays can relieve the burning of a sting.
- If you or the person bitten starts exhibiting allergic reaction symptoms–feeling faint, dizzy, swelling, trouble breathing–go to the ER.
How to Get Rid of Fire Ants
Fire ants can be hard to get rid of. The mound may seem to have been killed, but really, the queen was moved, and they’ll be back too soon. There is an entire body of folklore, urban legends, and home concoctions that people claim to work, but most often, they are killing some worker ants, which are quickly and easily replaced. The queen is kept far underground, and it’s her you need to get rid of.
Some fire ants are territorial, giving rise to the idea of taking a shovel of ant mound (and ants) from one colony and dumping it on another. I suppose that’s a fight fire with fire idea, but it seems fraught with peril and hasn’t been proven to work. Diatomaceous earth sprinkled around the mound, dumping grits on it, and even dousing it with gasoline and lighting it on fire are all methods you’ll hear if you prowl the internet forums, but they aren’t universally effective or even safe. While drowning the mound in boiling water is effective more than half the time, you need a lot of boiling water, about three gallons, and handling that much hot water is a major safety issue.
The most effective treatment homeowners have access to is bait (which contains an insecticide). Treating an area with a single bait application can reduce fire ant populations by 80%. The ants find the bait while foraging and bring it back to the colony, where it can kill many ants and hopefully, the queen.
If you’ve only got a few mounds, you can treat each mound directly. If new mounds are starting to pop up all over, you’ll need to treat the entire area and individual mounds using the two-step method below to knock them back.
Treating a fire ant mound in your vegetable garden
If you’ve got a mound or two in your yard or garden but not a major infestation, you can treat the individual mounds. Many products are sold, including drenches, granules, and powders. Usually, they are applied to the top of the mound and then watered in to penetrate down into the colony. Dosage varies according to the product used, so follow the label. Check out this guide from Clemson Cooperative Extension for product recommendations for treating fire ant mounds in your vegetable garden.
The “Two-Step” Method
No, this isn’t dancing on the mound (which is highly discouraged). Rather, it refers to a two-step process that treats both the area and the individual mounds.
With the two-step method, an area like a yard is treated with a broadcast bait product similar to spreading fertilizer. Then, nuisance mounds are targeted with a higher potency, faster-acting method. Covering an entire lawn is expensive and time-consuming. If you only have a few mounds, skip to step 2.
- In spring and fall, treat the infested area with a broadcast bait insecticide. These baits are gathered by the ants and taken back to the colony, where they not only affect workers, but hopefully the queens as well. Many products are on the market, and some are listed as organic by the Organic Materials Review Institute (OMRI), meaning they are a better choice near your veggie patch. Fire ants will forage over a wide area, so you can keep the bait outside your vegetable rows unless you have mounds in the middle of a large garden.
- Treat nuisance mounds in high-traffic areas by sprinkling or covering the mound with a product labeled as a fire ant insecticide. Follow the directions on the package. Mounds may need to be retreated several times to get the queen.
The University of Florida Extension publishes several guides. Check out this page for more details on application rates and timing for the two-step method.
How to Reduce Problems with Fire Ants
While preventing fire ants isn’t really possible (if it were, we wouldn’t have an invasive species issue), there are things you can do to minimize the problem.
- Treat mounds as they pop up; don’t wait until your yard has several dozen new nests. Continued suppression effort is more effective.
- Coordinate with neighbors. Making your property inhospitable for these invasive ants is more effective if you can get a few of your neighbors on board and you all act together.
- Talk about the hazards of fire ants with children and visitors. Friends and family from locations without a fire ant problem may not be aware of the problem or know what to look for.
Andy Wilcox
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