How to Identify & Control Fire Ants

Fire ants are a dreaded problem because of their aggressive nature and painful bite.

In general, ants are a nuisance, but some species are more than mere pests. Fire ants, found throughout western and southern parts of the U.S., are a particular problem because of their painful bites and stings. These ants will aggressively protect their mounds by attacking interlopers who either deliberately or accidentally disturb the mound. The following information can help you identify these insects and take steps to effectively remove them from your yard.

Identifying Fire Ants

Although multiple fire ant species exist, arguably, the most impactful species of fire ant in the United States is the invasive red imported fire ant (RIFA). The queen and worker RIFAs have a reddish-brown head and thorax with a black rear segment (although there may be variations in color). Male swarmers are completely black. Workers are polymorphic (meaning they vary in size), ranging from 1/16-1/4 inch in length. Fire ant workers have a venom-injecting stinger as well as mandibles used for biting.

One way to distinguish fire ants from other red ants is that they have a 2-segmented pedicel, which looks like two bumps on the ‘waist' of the ant—the area between the thorax and abdomen. Their thorax lacks spines, and they also have 10 distinct antennal segments with a 2-segmented club at the ends.

What Is The Habitat of a Fire Ant?

Many people are able to identify fire ants by spotting their telltale mounds. These ants are typically ground-nesting and will build their mounds in virtually any kind of soil, but tend to prefer sunny locations that include lawns, fields, and pastures.

Mature mounds are, on average, 10-24 inches across and 6-18 inches high but may be larger or smaller. There is a tendency for fire ants to build mounds near driveways and sidewalks that absorb and give off heat. People have also spotted their mounds in rotting logs, near trees, and even beneath buildings. However, a lack of mounds does not mean that there are no fire ants present. Fire ants also create an elaborate underground tunnel system that can extend up to 25 feet away from a mound. A large colony can have as many as 250,000 worker ants that are well known for their active and aggressive natures; however, the average fire ant colony typically consists of around 80,000 workers.

During hurricanes or other flooding, fire ants will often be forced to leave their nests to look for dry land. To do that, they will form living rafts that drift on the water until the ants reach a landing spot, such as a tree trunk or the foundation of your house. They may even come inside the house to search for food.

What Do Fire Ants Eat?

Fire ants prefer foods with high protein content, but will feed on almost anything, including plants and animals. They tend to feed on insects, young tree bark, seeds, and prefer oily meat or nuts. These ants will also dine on carrion (dead, decaying animals) that they happen to locate when foraging.

Are Fire Ants Dangerous?

While a single sting for most people and pets is bothersome and painful, it is more common to be stung multiple times by multiple ants. Most of these attacks occur when the ants' mound is disturbed. Hundreds of ants can sting multiple times during a single attack which can lead to severe reactions even those with a strong immune system. If a person experiences a serious reaction, like nausea, sweating, or shortness of breath, as the result of a fire ant sting, they should seek immediate medical care. A very small percentage of people in the U.S. (approximately 1-2%) are at risk for anaphylaxis if stung by fire ants. The key to avoiding being stung outdoors is to be vigilant in areas where they are likely to be present, and to watch where you step in order to avoid disturbing the nest.

How Do I Get Rid of Fire Ants?

If you spot fire ant mounds in your yard, you should take a 2-step approach to killing them. First, apply Ortho® Orthene® Fire Ant Killer1 or Ortho® Fire Ant Killer Mound Bait to the mounds you see around your yard, following label directions. Then, apply Ortho® Fire Ant Killer Broadcast Granules as a broadcast treatment over your entire lawn. This will keep new fire ant mounds from forming for up to 6 months. If you live in an area prone to fire ants, continue to routinely inspect the perimeter of your home and your entire yard for signs of invasion.

Do Fire Ants Get Inside Homes?

Fire ants can get into the home just like other ants do. They may create nests that put them close to foundation cracks, for instance. They may also enter through HVAC units, typically after being displaced following rain or flooding. They may also access the home via electrical boxes.

One way to help prevent these pests from getting into your home is by caulking cracks and holes. You can also create a barrier around your home with Ortho® Home Defense® Insect Killer for Indoor & Perimeter2. If the fire ants are already nesting in your home, kill them with Ortho® Home Defense® Ant, Roach & Spider Killer2 or Ortho® Home Defense® Insect Killer for Cracks & Crevices.