Fire Ant Season Heating Up

San Antonio Express News
Sunday, May 4, 2003

Logo for Texas Imported Fire Ant Research and Management Plan

By Nathan Riggs

Spring time temperatures have stabilized in San Antonio and many of the local plants, animals and insects are thriving. Fire ants are one of the local insects that enjoy the warm, sunny weather of spring. This week’s article from the Bexar County Extension office will talk about a new addition to the fire ant treatment toolbox; it happens to be organic too!

Treating for fire ants should involve only one consideration: number of mounds per lawn area. In the average lawn, a mound number of 5 is the decision factor. Less than 5 mounds dictates an individual mound treatment of any product type, while a number of 5 or more dictates a broadcast treatment of some kind.

For those with less than 5 fire ant mounds, treating the mounds individually or not all is the way to go. Treatments range from hot water drenches to organic treatments to conventional chemicals. They all have varying degrees of success, but work best on freshly built or relatively new mounds. Degraded mounds require an additional gallon of water following treatment.

For those with heavy (more than 5 mounds) infestation of fire ants, broadcastinga fire ant bait is the way to go. Broadcast treatments using fire ant baits such as

Amdro, Award, Extinguish, or Distance should be applied at 1 lb per acre rates on dry days without lawn watering. This method saves time, money and is target-specific for fire ants. Three to five days following the bait treatment, treat only “nuisance” mounds in high traffic areas with a fast-acting product. This treatment strategy is called the “Two Step Method” of fireant control.

Broadcasting fire ant bait is not new, it is just not well-known. Broadcasting the bait makes the “food” more available to the foraging fire ant workers, which in turn get the poison more efficiently to the queen ants at home.

2 step logoNew for 2003 is the availability of an “organic” Two Step Method. Fire ant baits containing the active ingredient, spinosad, will replace those listed above to make an “organic” version. Spinosad is extracted under a fermentation process from a soil bacterium, therefore giving it a natural origin. Baits that contain spinosad are made by Ortho, Dow Agrosciences (Justice®), Ferti-lome and Justin. The application rate is higher (3 lbs/acre) than other baits and works just as well. For the nuisance mound treatment, use hot water, orange oil or d-limonene products, pyrethrin products or other naturally-derived products. Do not use grits, because grits do not kill fire ants.

Fire ant control products seem to be as numerous as stars in the sky. Many of them contain the same active ingredients, but have different packaging. The most important considerations when treating fire ants are following labeled instructions for where to treat and how much to use. Fire ants are very easily killed by insecticides applied at the recommended dosage. In this case, more is not better.

For more information on fire ant management, call Nathan Riggs at the Bexar County Extension office at (210) 467-6475 or go to the Texas Fire Ant Program website at


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