Fire ants around the house

Published on Saturday, 7 June 2014 21:56 - Written by Chad Gulley Extension Agent

With the recent rainfall in the area, many people now are starting to see fire ant mounds popping up in their lawns and flower beds. Fire ants are estimated to cost Americans $6 billion annually. While there may not be one best method for fire ant control, seek methods that are cost-effective yet environmentally sound.

Mounds seem to ‘pop up’ overnight. Fire ants need water to survive and most fire ants colonies live underground using an extensive network of underground tunnels to forage for food. When we get rainfall in fall and spring months, above ground mounds start to form. The ants build these individual above ground mounds from soil blocking some of their tunnels. In these above ground mounds while the weather is optimal, fire ants brood development occurs.

Fire ants broods are sensitive to temperature and humidity. Why do ant mounds disappear during hot, dry weather? When we are in periods of dry weather, the ants move underground. Some can go as deep as four feet deep to seek a more suitable environment for the ant colony during the hot, dry periods of the year.

The Texas Two-Step Method is just one option for those seeking control of fire ants around the home. Step one is to broadcast an insecticide bait once or twice a year which can reduce fire ant colonies by 80 to 90 percent. Step two is to treat nuisance mounds or colonies that move into the bait-treated areas. Step two may not always be needed.

The bait you apply determines how quickly ants will be controlled and how long the effect will last. Insecticides for fire ant control are formulated as dusts, granules, liquid drenches, and baits. The various active ingredients in each formulation will affect ants in different ways.

Contact insecticides for fire ant control include acephate, carbaryl, fipronil, spinosad, deltamethrin, and cyfluthrin to name a few. Bait insecticides for fire ant control include abamectin, indoxacarb, spinosad, fipronil, hydramethylnon, fenoxycarb, and methoprene to name a few. These bait formulations affect the fire ants in a various ways. Since fire ant baits affect ants in different ways, be patient as some products may take several weeks to offer adequate control of the fire ant colonies.

For baits to be effective in fire ant control, the bait must be fresh and applied at the correct time of day. Baits applied when the ants are actively foraging can be more effective. To determine if the time is right to be treated, place a small amount of the bait in the area to be treated and see if the foraging ants remove it within an hour.

Read and follow all label instructions when controlling fire ants. Some fire ant bait products are not effective if water by irrigation or rainfall comes in contact with the bait soon after it is applied. Today’s fire ant baits are gentle on the environment and are best applied using crank-type seeders or spreaders.

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