Red Imported Fire Ants
What are Red Imported Fire Ants?
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Red Imported Fire Ants (RIFA) are destructive, invasive ants that cause millions of dollars worth of damage to agricultural, residential and recreational lands each year. Their foraging activities can damage crops, lawns and ornamental plantings. The large mounds that these ants build are unsightly and can cause damage to the structures they are near. They are also a serious concern to human health and wildlife because they can repeatedly sting an individual resulting in very painful, burning blisters. Their reddish-brown color, aggressive swarming behavior and painful stings give these ants their name.
Where did Red Imported Fire Ants come from and what is their current distribution in the United States?
RIFA accidentally gained entry into the United States through the port of Mobile, Alabama in the late 1930's in soil used as ballast in cargo ships from South America. Due to the lack of natural enemies, they quickly established colonies and began spreading into adjacent areas through the aid of human movement of infested soil and nursery stock. They are now found in 13 states in the U.S, including Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, and Texas, as well as Puerto Rico. Isolated colonies have been found in Arizona, Kentucky, Virginia and Maryland but have not become established.
How can I identify Red Imported Fire Ants?
Red Imported Fire Ants (Solenopsis invicta Buren), belong to the Order Hymenoptera, Family Formicidae. Like other ants, they are relatively small, ranging in size from 1/8 to 1/4 inch in length and are reddish brown in color. These ants prefer to build large mound-shaped nests of excavated soil in open areas such as lawns, meadows, pastures and agricultural fields. RIFA mounds have also been seen near open areas against trees, mailboxes, around electrical wires and conduits, under sidewalks and roads, and even in the walls of buildings. Mounds of mature colonies may be as high as 2 feet and may extend 3 to 4 feet underground. These ants are extremely aggressive and respond rapidly to any disturbance of the nest or food resource. RIFA have a painful bite, but they are probably most notorious for their sting.
Why should I be concerned about Red Imported Fire Ants?
The sting from a RIFA can cause severe pain, discomfort and reactions in allergic individuals. The mere presence of RIFA can deter outdoor activities in yards, parks, and school grounds. An active colony may contain up to 300,000 workers and their foraging behavior around and inside homes can threaten animals, small children and the elderly. RIFA are major agricultural pests and are known to damage more than 50 different species of cultivated plants by feeding on germinating seeds and damaging developing fruit and flower buds.
How do I know if I have been stung by Red Imported Fire Ants and what should I do if I have been stung?
RIFA will rapidly swarm onto, and repeatedly sting, anything that disturbs them. Within seconds after a RIFA stings an individual, a red welt will form with an intense burning pain at the site. The pain may continue and the area may start to itch over the next few hours as the welt turns into a blister and eventually into a white pustule. The pain and itching may continue for the next several days or more before subsiding. A minority of those stung by RIFA are hypersensitive to the venom and can react quite severely, suffering chest pains, nausea, dizziness, shock or, in rare cases, lapsing into coma. Deaths resulting from RIFA stings have been documented but are rare. Hypersensitive individuals should seek medical attention immediately by contacting their physician or local Preventive Medicine personnel. Avoid scratching or rubbing the blisters to prevent bacterial infections and scarring.
What can I do to prevent Red Imported Fire Ants from colonizing my home or quarters?
RIFA have a nasty habit of hitching rides, so regularly inspect cars and recreational vehicles to prevent them from tagging along. Also, inspect yards, nursery stock, plants, sod, firewood, hay, soil or other items for the presence of RIFA and their mounds.
Should I use home remedies to control Red Imported Fire Ants?
No, the use of home remedies is not recommended. Boiling water and the use of flammable materials may kill ants on the surface but do not kill the queen. Such "treatments" are rarely effective since the queen is generally located too deep in the nest to be destroyed by simple drenching or burning. Attempting to drench fire ant mounds with such materials or to drown or incinerate nests using such materials is dangerous to the individual and harmful to the environment.
What is recommended for control of Red Imported Fire Ants on property around my home or quarters?
Baits in the form of broadcast granular products are very effective and can give very high levels of control. Baits are designed to attract foraging RIFA who pick up the bait and carry it back to the nest where it will be consumed and either kill the queen or render her sterile. EPA registered active ingredients for RIFA control include methoprene, abamectin, hydromethalon and fenoxycarb. Individuals applying any treatment should read product labels carefully and follow all directions. Although baits are slow-acting, their use is often the best way to reach the queen and eliminate the colony.
