Oklahoma State University

Two Step Method


Step One - Baits


Fire ant baits consist of pesticides on processed corn grits coated with soybean oil. While baits can be applied as an individual mound treatment, they are best used as a broadcast treatment. Broadcast treatments are less expensive (in terms of product costs as well as time) and control colonies even whey mounds are not visible. For best results:

  • Use fresh bait, preferably from an unopened container or one that has been tightly sealed and stored for no more that two years.

  • Apply when the ground and grass are dry and no rain is expected for the next 24 hours.

  • Apply when worker ants are actively searching for food. This can be determined by leaving a small piece of food (chips or meat) near an active mound. If ants are seen removing the food within 10 to 30 minutes, it's a good time to begin application. Ants are less active during cold and hot periods (when soil temperature is less than 70 F or greater than 95 F).

  • In the summer, apply bait in late afternoon or evening, when ants are most active.

  • Baits can be applied with hand-held seed spreaders. Set the spreader on the smallest opening and make one or two passes over the lawn at a normal walking speed to apply the recommended rate (1 to 1.5 pounds per acre, or approximately 4 ounces per 10,000 feet).

  • Bait products contain different active ingredients that work in unique ways. Hydramethylnon (Amdro) is a slow acting poison that causes approximately 80 to 90 percent of the mounds in a treated area to become inactive within one to five weeks. Fenoxycarb (Award) and Avermectin (PT 370 Ascend for pest control operators) act as insect growth regulators. Their main function is to keep queen ants from producing more workers. It may take five to ten weeks or more for results to be seen, but as many as 90 percent of the fire ant mounds in treated areas may be eliminated. Control may last up to a year in areas larger than an acre. Smaller yards may show less dramatic results because they are more easily re-infested from adjacent untreated sites.

    Step Two - Individual Mound Treatments


    Individual mound treatments should be made at least three days after bait application. There are a variety of chemical and non-chemical methods for treating fire ant mounds one at a time.

    Chemical Treatments: Some products, such as those containing acephate, are formulated as dusts. Ants walking through the treated soil get dust on their bodies and transport the insecticide into the mound. Within a few days the entire colony should be killed. To use a dust, distribute the recommended amount evenly over the mound. Do not inhale the dust or get it on your skin.

    Liquid concentrates are diluted with water and then applied to the mound. These liquid mound drenches kill the ants underground, but must be applied in sufficient volume to penetrate the entire nest (1 to 2 gallons of diluted mixture poured over the top of each mound). Mound drenches generally eliminate mounds within a few hours. When handling liquid concentrates, avoid getting the product on your skin by always wearing unlined rubber gloves. Mix the insecticide in a container such as a sprinkler can. Write "Poison" on the container and do not use it for any other purpose.

    Granular insecticides are released when water is poured over the granules on treated mounds. To treat a single mound, sprinkle the recommended amount of granules with a measuring cup on top of and around the mound. Then, gently sprinkle 1 to 2 gallons of water over the treated mound to avoid disturbing the colony or washing the granules off the mound.

    Remember, if you apply less than the recommended amount of water with either liquid concentrates or granular insecticides you can expect poor results. Unless the product completely penetrates the mound, ants will move to a different site via underground foraging tunnels to avoid the poison.

    Some products come in aerosol containers to which an infection rod is attached. The rod is inserted into the mound and the insecticide injected according to the label instructions for a quick kill of problem mounds.

    Low toxicity and non-chemical treatments: A few active ingredients used in fire ant control products are commonly referred to as "organic" or "least-toxic" (e.g. boric acid, pyrethrins, rotenone and diatomaceous earth). Diatomaceous earth, a natural silica-based dust, will kill some ants, but is not very effective when the soil is moist and it rarely eliminates ant colonies when used alone. The effectiveness of products containing pyrethrins and boric acid, as compared to standard insecticides, has not been adequately determined.

    Boiling water (about 3 gallons per mound) will eliminate about 60 percent of the mounds treated, but this treatment can be hazardous for the person transporting the hot water. Surviving mounds will need to be treated again. Care must be taken not to pour boiling water on grass or other plants.

    Tips for Monitoring Red Imported Fire Ant Activity


  • In summer when temperature is above 90 F, monitor in midmorning or late afternoon.

  • Place a corn chip or small piece of meat 4 to 5 feet from visible mound.

  • Place several more chips further away from mound; continue for up to about 100 feet.

  • Check for ant activity 30 minutes after distributing chips.

  • Apply baits to areas of foraging fire ants.

    Home remedies: Many "home remedies" have been used or proposed to control fire ants. They are not recommended, but a discussion of some of them is presented here for information only. While these methods often appear to work, they rarely control ants. Usually the ant colony simply moves to a new location, or the queen and a few workers remain hidden underground.

    Gasoline and other petroleum products have been widely used, and they do kill fire ant colonies. However, petroleum products are dangerously flammable, kill grass and plants around the treated mounds and can seriously pollute the soil. The cost of gasoline compared to fire ant products makes this method expensive.

    Other home remedies include soap solutions, cleaning products or wood ashes soaked into the mound, all of which are believed to remove the protective oil coating from the ants. The use of battery acids, bleaches or ammonia products is extremely dangerous. All of these products are potentially serious pollutants.

    Another technique is the sprinkling of grits on fire ant mounds. The theory is that the ants will eat the grits, which will then swell and rupture the ants' stomachs. No scientific research supports this claim. In fact, only the last stage of the developing fire ant is known to ingest solid food. All other life stages feed only on liquids, sugary solutions or greasy materials.

    Substances released from crushed or grated citrus peels, and other natural substances, have been reported to be toxic to fire ants. However, until proper techniques have been developed for applying these naturally occurring chemicals they are likely to be ineffective.


    • Division of Agricultural Sciences and Natural Resources