Fire ants presently infest more than 125 Texas counties and their westward migration continues. Three native Texas fire ant species exist – the commonly found tropical and southern fire ants, and the rarer desert fire ant. It’s the red imported fire ant species, however, that’s causing the most concern. This destructive species of fire ant was first introduced in 1930. Since then, imported fire ants have winged their way across nine southern states from the Carolinas to Texas.
They’ve also spread by crawling, drifting down rivers on logs or traveling aboard vehicles. Shipments of nursery stock or soil from infested areas can relocate entire ant colonies.
While fire ants do feed on insects and other pests, their destructive nature far outweighs any benefits. They damage young plants by gnawing holes in roots, tubers, stalks and buds and sometimes they attack newborn livestock and wildlife. In addition, fire ant mounds – which often are large and as hard as concrete – can damage machinery, hinder mowing operations and reduce land value.
Fire ant infestations are particularly hazardous in lawns, parks, playgrounds, school yards and homes. Animals and people that disturb fire ant mounds will be stung repeatedly. Symptoms of the sting include burning and itching, often followed by a white sore or pustule that may leave a scar. Some hypersensitive persons may react to the venom and suffer chest pains or nausea and even lapse into a coma from one sting. Here is how to get rid of fire ants:
Chemical control techniques
Chemical applications can be aimed at the foraging worker ants and/or the entire colony. Available techniques include surface applications using paints, sprays, or dusts; individual mound treatments using drenches, granular products, dusts, methyl chloroform, aerosols or baits; and broadcast applications of insecticide liquids, granuals or baits using granulators, high volume sprays and electric or mechanical spreaders.
Many products containing carbaryl, chlorpyrifos, diazinon, propoxur and resmethrin are labeled for indoor and/or outdoor use as spot treatments for fire ant trails and for ant colonies located in wall voids. They are generally formulated as dusts or sprays, although several products contain chlorpyrifos mixed into a latexbased paint.
Except when used to treat colonies located in wall voids, these products are intended only to reduce the number of foraging worker fire ants, the colony where ants are developing is not directly affected. These products can be used to produce barriers and protect items or areas where foraging worker ant activity is not wanted.
Individual mound treatment (mound drenches)
Most fire ant control products on the market are formulated as liquid concentrates. A few are available as ready-to-use formulations. Each product contains a certain concentration of insecticide which may need to be diluted in the amount of water specified on the product’s label.
Be careful in handling the concentrate and avoid contact with it. Mix the proper amount in a gallon container such as a sprinkler can or plastic jug with holes drilled in the screw-on cap. Do not use a container which may be readily identified with a food product.
Plainly mark “poison” on the container and do not use the container for any other purpose. Destroy it after use. Sprinkle the solution on top and around the mound gently without disturbing the fire ants colony. Mound drenches do not kill ants immediately and may require several days to be effective.
You can also get rid of fire ants using several products that contain insecticides formulated as granules applied to individual mounds at the rate specified on the product’s label. Treat a single mound, measure the recommended amount in a measuring cup and sprinkle it on top of and around the mound. Do not disturb the mound.
Then, using a sprinkling can, water mound gently, trying not to disturb the colony. Several days may be required before the entire fire ants colony has been killed.
Some products, such as those containing acephate, are specifically labeled for dusting individual fire ant mounds. Evenly distribute recommended rates of the powder over the mound. The mound should be eliminated within approximately one week.
Several products contain pesticides formulated on a bait of processed corn grits coated with soybean oil. These products are applied around individual mounds or to larger areas at rates specified on the product labels. Baits should be applied when worker ants are actively foraging. This can be determined by leaving some greasy foods such as tuna fish or peanut butter near a mound and checking it for fire ant activity or observing ant trails around mounds when temperatures exceed 70 degrees.
During hot summer days, the worker ants forage during the night and are inactive during the day. In most situations, baits should be applied in late afternoon or early evening. To treat individual mounds sprinkle the recommended amount of product around, but not on the undisturbed mound. Bait can be sprinkled up to three feet away from the mound. Depending on the active ingredient, several days to many weeks may be required to eliminate the mound’s fire ant population.
Several products are labeled for broadcast application. To get rid of fire ants in turf grass, granular formulations can be applied with a fertilizer spreader or liquid formulations can be applied using a high volume hydraulic sprayer. These materials must be thoroughly watered into the soil.
Granular products containing diazinon, chlorpyrifos or isofenphos are long-acting contact insecticides which primarily kill foraging worker ants and prevent small mounds from being established.
Although insecticide treatment may reduce the numbers of workers or eliminate mounds temporarily, reinfestation is likely to occur. To get rid of fire ants, control programs must be carefully designed and implemented. These programs are generally more successful when treatments are repeated periodically or as needed, or when a combination of control tactics are implemented in succession. Many good insecticides are available, follow directions on label.