Fire Ants on the Move

Rene Schmit  |  4/29/2014 11:54:53 PM

Now that warmer temperatures have arrived, fire ants are on the move and that means potentially an increase in fire ant mounds throughout the lawn and bedding areas of the home landscape. Fire ants begin an active colonization and foraging when soil temperatures warm up above 70 degrees Fahrenheit. Left alone, fire ants not only will increase in number but also in the number of new colonies and mounds. The good news is that fire ants can be controlled effectively by treating individual mounds, applying bait, and/or applying a general use insecticide.

Baits are used in broadcast treatments that involve applying the bait across the infested area. Ants perceive the baits as food, which is picked up by worker ants and taken back to the nest and fed to the rest of the colony. Baits are insecticides that have been impregnated into ground corn cobs and treated with soybean oil. The oil attracts the ants, and the insecticide kills them. Baits often have a reduced shelf life because the soybean oil that’s used as an attractant tends to turn rancid after a short period of time. Therefore, it’s important to always use fresh bait to be sure your insecticide is effective. Keep in mind that baits are generally only effective in the area where they’re distributed. This means that if homeowners treat only their own properties, fire ants may move in from a neighboring lot. Common active ingredients for baits include abamectin, indoxacarb, hydramethylnon and spinosad and are found in products such as Amdro, Logic, Award, Extinguish, or Spectracide Fire Ant Bait.

Broadcast (general use) granular insecticides are another type of fire ant control. These insecticides work by forming a relatively long-lasting barrier on the soil surface. The residual control of a particular broadcast granular insecticide however will depend on its active ingredient. Generally information relating to the length of control or the residual is often found on the bag label. Common active ingredients in granular formulations include gamma-cyhalothrin, bifenthrin, lamda cyhalothrin, deltamethrin and are found in products such as Over and Out Fire Ant Killer, Bug Blaster, Once and Done, or Talstar.

Individual mound treatments may be used in combination with broadcast treatments to eliminate the mounds before the broadcast material has taken effect or to eliminate colonies that the broadcast treatment may have missed. Insecticide mound treatments include dusts, granules and drenches. Most product labels for fire ant mound treatments state specifically where the labeled dosage should be placed. Granular insecticides for mounds for example, are applied and then watered in. Common active ingredients for mound treatment insecticides include hydramethylnon, bifenthrin, acephate, carbaryl, lambda-cyhalothrin, deltamethrin and spinosad. While most mound treatments are watered in, baits and broadcast granular insecticides must be applied to dry lawns to be effective. Whether using a bait, granular or mound treatment always be sure to follow label directions for ensuring safe use and an effective control.

Rene’ Schmit is the St. Charles Parish County Agent of the LSU AgCenter and can be reached at 985-785-4473.
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