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Red Imported Fire Ants

Red Imported Fire Ants Informational Bulletin
Red Imported Fire Ant

Red Imported Fire Ants (RIFA) are very aggressive ants that are native to South America. They vigorously defend their nests, attack in large numbers and sting repeatedly. For a small percentage of the population who are allergic to the venom, RIFA stings can be fatal for the very young and old, as well as anyone else unable to escape the attack. 

May contain: wrist, hand, arm, human, and person

Red Imported Fire Ants inflict painful stings that form pustules, itching for up to two weeks.

Humans are not the only ones subject to RIFA attacks; ants will be attracted to pet food left out and will sting when disturbed by a hungry pet. These attacks can be quite serious since the first part of the animal to get stung is usually the muzzle. If there are enough stings in the right place, the swelling caused by the venom can obstruct breathing.

The toll taken on wildlife can be considerable. The numbers and variety of reptiles and amphibians remaining in an area infested by RIFA is a fraction of what was there before. Any ground or low nesting birds will be impacted as well.

May contain: outdoors, plant, road, dirt road, and gravel

The attraction of RIFA to electrical current creates a whole new set of issues. Any outdoor electrical equipment is subject to damage by Red Imported Fire Ants. Air conditioners, spas, outdoor lighting and irrigation controllers are all commonly damaged by RIFA in areas where the ants have become established.

Currently, much of Southern California, including all of Orange County, is under nursery quarantine. Nurseries in the quarantine area must bait survey the entire property every 90 days. They must also treat every piece of plant material they ship, regardless of the survey results. Treatment is usually done by incorporating a pesticide into the soil mix at planting time. Not only is this procedure expensive, but the amount of pesticide being used also means runoff is likely to become an issue.

What We Do

If you think you have found a Red Imported Fire Ant (RIFA) colony, call the Orange County Mosquito and Vector Control District (District)  and an inspector will be out to visit the site within 1-3 business days. The District will determine if the colony is actually RIFA. Once RIFA are confirmed, treatment with an insect growth regulator (IGR) or a metabolic inhibitor (MI) will begin. RIFA cannot consume solid food; they filter the solids out and digest the liquid. Each of these materials is very effective at eliminating RIFA colonies. IGRs work by blocking the development of immature ants. Consequently, as the ants get older and die, they are not replaced. Metabolic inhibitors block the utilization of food. RIFA can continue to eat, but they derive no benefit from what they consume. The worker ants pass the material on to the queen.


The District has a multifaceted RIFA education program that includes:

  • Presentations and participation in local outreach events to educate the public about RIFA control practices.
  • The creation and distribution of training DVD’s for landscape professionals to educate their staff about RIFA biology and control strategies.
  • Extensive literature on RIFA control practices, local ants that resemble RIFA, and many other publications are available in print and electronically.
  • Inspectors educate homeowners and neighborhood groups about how to identify the presence of RIFA on their property and how to eliminate them.
  • Staff attends local and national educational conferences to learn about advances in RIFA control techniques, products, and other measures to better educate and protect the public from Red Imported Fire Ants.