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fire ant moundFire ants have spread throughout much of south and eastern parts of North Carolina and mounds have been found in counties further west where the ants have been introduced accidentally in landscaping and soil placed around new residential and commercial developments.

Fire ant mounds vary in size, usually in direct proportion to the size of the colony. For example, a mound that is 2 feet in diameter and 18 inches high may contain about 100,000 workers, several hundred winged adults, and one queen. The mounds are usually located in exposed areas, often near trees (as shown here). You may accidentally step on a nest or grab fire ants during cleanup activities in the yard. In areas of severe flooding, fire ants may even form a "ball" or "raft" and float in the water until they find 'dry land', such as a tree limb or some object. These ants can pose problems during rescue efforts and other activities in flooded areas.

fire ant stings on legWhen disturbed, fire ants can deliver painful stings. Within 24 hours after a person is stung, a pustule-like sore usually forms at each sting site, which then usually itches intensively. Scratching the pustule may rupture the skin, leading to secondary infection and scarring. Just as with bee and wasp stings, a small proportion of people are highly allergic to fire ant stings and require medical attention after a stinging incident.

Fire ants are particularly fond of greasy-oily foods. While they typically an outdoor problem, disturbances during/after severe weather may bring them indoors in search of food or even "dry land" and thus into closer contact with people.

Here are some suggestions to follow if fire ants are common in your area:

  • Watch where you step when clearing debris in yards,
  • Insect repellents are not likely to be effective against fire ants.
  • When eating outside, keep all food and drinks covered while they are not being eaten. Dispose of food in garbage bags and trash cans. Keep trashcans covered and (preferably) away from the house.
  • Indoors, do not leave food exposed on tables, countertops or floors (in the case of dry pet foods).
  • If your need to treat a fire ant mound that is disrupting cleanup and other activities, drench the mound with a liquid insecticide. Products containing Sevin, cyfluthrin or bifenthrin and permethrin should work. Fire ant baits work well, but they also take significantly longer time to effectively reduce the ant population. A list of products that can be used against fire ants is available in the North Carolina Agricultural Chemicals Manual.
  • For additional information, consult Control of the Red Imported Fire Ant

Photograph of fire ant stings by Daniel Wojcik., USDA-ARS

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