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Fire Ant Identification, Control and Prevention


Fire Ant Identification, Control and Prevention
Photo courtesy of USDA/ARS

Although the Northern U.S. is fortunately free of fire ants, this biting and stinging ant is common in the Southernmost U.S. states and and up to the mid-U.S. on both coasts. They are most common in the Southeast across to Texas.

The U.S. has both native and imported species of fire ants, with the most common being the red imported fire ant.

What do fire ants look like?

In many ways, fire ants are almost indistinguishable from other ants to the naked eye:

  • Fire ants are very small and reddish brown to black in color.
  • However, unlike most other ants which are generally of the same size, fire ants can vary from 1/16 inch to 1/4 inch long within the same colony. This is, in fact, an identifying characteristic of the ants
  • Additionally, they are very aggressive, attacking anytime their mound is disturbed.
  • With magnification, it can also be seen that these ants have:
    • 10-segmented antennae with 2-segmented club
    • a stinger, two-segmented pedicel

Four species are commonly found in the southeast U.S. including two native species:

  • tropical fire ant, Solenopsis geminata Fabricius,
  • southern fire ant, S. xyloni McCook

and two imported species (introduced from South America):

  • black imported fire ant, Solenopsis richteri Forel
  • red imported fire ant, Solenopsis invicta Buren

The four species, however, can be very difficult to tell apart, primarily because the native species interbreed as do the imported species. And because they all cause damage and harm humans and animals, there generally is little need for the homeowner to differentiate between them.

What damage or harm do fire ants cause?

According to the Texas A&M AgriLife Extension and Research services, the impact of red imported fire ants in Texas is estimated to be $1.2 billion annually. The ants cause harm and damage to people, plants, and animals in both urban and rural areas.

Some of this harm and damage, as identified by the University of Minnesota, includes:

  • Fire ants will damage almost 60 species of cultivated plants.
  • They will sting birds and mammals reducing rural populations.
  • Fire ants nest in the walls of homes and city buildings -- can enter homes to be of danger to residents, particularly small children and the elderly.
  • They also have been found in cars, trucks and RVs – and can have even been the cause of accidents when they stung the drivers.
  • People will often avoid yards and parks in order to protect themselves from possible fire ant colonies.
  • They will build colonies under sidewalks and roads, which can cause cracking or even collapse of these when the fire ants seek out a new site.
  • And ants in colonies near roads have been known to attack accident victims who are thrown from their cars and too injured to get away from the ants.

How do you know if you have fire ants?

Some of the most common signs of fire ants, according to Texas A&M, are:

  • Fire ants build mound-shaped nests that look like fluffy worked soil.
  • The mounds can be up to 18 inches tall in rural, undisturbed areas. However most are only a few inches tall.
  • The mounds are most prominent after heavy rain.
  • The mound also will look different than other ant mounds in that you will not see an opening in the center of the mound. Fire ants do not spill from the top of these mounds, but have a network of underground tunnels through which they enter and leave.
  • If you were to disturb the mound, the ants will surge out around the mound, climbing up nearby grasses and vertical surfaces, and attack the person, animal, or thing that disturbed their nest.

Read more about:
Part 2: Fire Ant Control
Part 3: Fire Ant Bites, Fire Ant Stings

References and Resources
University of Minnesota
Texas A&M

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