The imported fire ant is a nuisance most of us are familiar with.
Fire ants can cause many problems. The sting is the most notorious and painful problem. They will sting repeatedly and attack anything that disturbs their mound or food sources. 
The name "fire ant" comes from the burning sensation the sting's venom causes. This venom can cause anaphylactic shock in sensitive people, resulting in death. Small children and pets are especially vulnerable to the fire ant.
The mature fire ant mound can rise to a height of 18 inches and a width of 24 inches. These mounds are unsightly and even a little frightening when they reach this size. More often they will be much smaller and harder to see in grassy areas. Always watch where you stand or sit in any landscape.
Fire ants like to congregate around areas of concentrated electrical power, such as air conditioners and transformers. Their propensity to chew on wire insulation causes electrical shorts and outages. They nest under patio slabs, walkways and roads, and cause damage and cracking when they leave the mound and it collapses. Fire ants damage the landscape by feeding on germinating seeds and the buds of young fruit trees. They also will girdle young trees and undermine root systems.
The fire ant mound begins with a single, winged queen that leaves an existing mound and mates in flight with a male. These flights usually happen in spring and early summer — and usually within a few days after a rainstorm, as the queen needs moisture in the early weeks of colonization.
Only 1 percent to 10 percent of the queens that take flight will succeed, due to air and ground predators and other hazards. If successful, the queen will rub off her wings and dig a burrow to lay a small number of eggs. The first workers that hatch tend to the queen and the subsequent eggs she lays until enough workers exist to gather food and build the mound.
Within six months a mound can contain several thousand workers. A mature mound, which takes about a year, can contain from 80,000 to 500,000 fire ants. Some mounds contain multiple queens.
Each member of the fire ant colony has a specific role to play that is key to the survival of all the members. The member around which all activity is centered is the queen. Without her the colony collapses.
The queen is serviced by a group of workers that perform the tasks required to keep the colony healthy and alive. These responsibilities include caring for the queen, watching over the eggs and larvae, clearing waste from the colony area, guarding the colony from invaders and foraging for food.
The colony has a keen sense of impending danger or threat and will move quickly to a new site when the mound is disturbed. In some cases, the mound will break off into several new colonies as the workers choose new queens and begin new mounds. This phenomenon can worsen an infestation if a colony is simply disrupted rather than destroyed.
Because the fire ant is not native to the United States, it had no enemies here. We have imported a new fly that decapitates the ants. It is showing some success.
Insecticides poured on the mounds will kill only the foraging workers. The real problem, the queen, is out of sight and reach of these insecticides. When the workers start to die, it creates a sense of danger within the mound that prompts the colony to quickly move the queen and eggs to a new site.
Insecticide baits such as Amdro are more effective than liquid insecticides. Workers will bring Amdro into the mound as food. If the queen ingests it and dies early on, it will be effective. However, if the mound discovers workers are dying for no reason, it will move the mound away from the danger.
Other bait granules contain an insect-growth regulator as the active ingredient. The queen will ingest it, and within days she will produce eggs that either will not hatch or produce sterile females. Workers are not reproduced and the number of fire ants in the colony will begin to diminish. The stress of the extra work load on existing workers speeds the mortality rate. The queen eventually dies.
These baits are effective because of their ability to enter the food chain without being detected. It is not seen as a toxin by the fire ants, and is therefore ingested without hesitation.
All baits should be applied around the mound without disturbing it and then broadcast bait, applied with a fertilizer spreader, should be used on the entire property. This will assure bait is picked up by any foraging ants whose colonies you might not have discovered.
We will probably never eradicate the imported fire ant altogether; but with diligence and the right chemicals, we can keep them under control on our property.