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CONSERVATION CORNER
(For the week of July 21, 2008)
Controlling Fire Ants
by James L. Cummins

Fire ant mounds are eye sores. However, looking at one isn’t nearly as painful as stepping in it. Fire ants, with their copper-brown head and body with a darker abdomen, came into Mobile, Alabama, on a South American cargo ship in the early 1900s. They are now all across the southern part of the United States and have even moved into parts of California.

A typical fire ant colony has large mounds in open areas and feeds mostly on young plants and seeds. They often attack small animals, including pets and livestock, and can kill them.

Moisture is essential to fire ant survival. Fire ants often nest near river banks, pond edges, watered lawns and highway edges. When the weather is hot and dry, they burrow deep into the soil to find moisture and cooler temperatures. When it’s cold, they burrow down to stay warm. But in warm, damp weather (spring or fall), fire ants are most likely to be active, foraging near the soil surface and building mounds.

Mounds can be up to 18 inches high. The nests can also be formed in rotting logs, around stumps and trees and in or under buildings. The ants guard the nests and fiercely attack intruders. Even the lightest touch brings them out in a fury.

If you have a lot of ground to cover, control can be time-consuming and expensive. Fire ant baits are a good, cost-effective method of control if you have few mounds. Baits are not to be confused with granular forms of insecticides. It works much slower than the granules. Bait is carried back to the colony and fed to other ants, including the queen and it affects her reproductive ability. Eventually the colony dies because no new ants are born to replenish the population. Baits don’t last a long time so it is best if the ants feed on them within a day. Late spring, or immediately after a rain, works best for bait.

If the infestation is larger, broadcast the bait and time the application for when the ants are out foraging for food. Try to avoid disturbing the mounds because the ants will flee back to protect the queen and they will usually move the colony rather than carry the bait back to the nest.

One common remedy used to get rid of mounds is a pot of boiling water. It is most effective when used right after a rainfall. At that time, a lot of the ants are near the surface and vulnerable to the scalding water. However, there are a couple of drawbacks to this method. Unless you kill the queen, the ants will just move to another part of your yard and construct another mound. Secondly, you may end up with a big brown spot on your lawn because the boiling water could kill the grass. Be very careful if you decide to use this method.