Stomping out fire ants

by Stephanie Suesan Smith on June 27, 2010

When I speak as a Master Gardener, I get more questions on fire ants than any other topic.  Red imported fire ants (Solenopsis invicta Buren) are loathed in the Southern parts of the United States.  These ants came into the US from South America in soil used as ship’s ballast in the 1930s.  Since then, they have spread like wildfire and show no signs of slowing down.

Fire ants are a very aggressive species that stings when the nest is disturbed.  The stings hurt like fire.  Some people are allergic to the venom and will die from one sting.  Most people, however, just hurt.

Fire Ant

photo by Bart Drees/Texas Agrilife Extension

In addition, fire ants are serious predators and have contributed to the decline of native species of ants, ground nesting birds, small mammals, and other animals.  They will even cover deer fawns and sting them to death.  The ants are attracted to electrical equipment and will chew through the insulation to the wires, resulting in shorts or even fires.  They also chew through water lines to get to the water.  It is estimated that fire ants cost Texas 1.2 billion dollars annually in damaged or destroyed equipment, killed livestock and native species, medical bills, and other things.  That is a lot of money!

Unfortunately, fire ants are hard to get rid of because they nest underground, where chemical controls have a hard time reaching them.  They also reproduce like mad and spawn new colonies of ants frequently.  If you have one mound today, you will have three in a couple of weeks.  Fire ants will probably inherit the earth, along with cockroaches, when humans have disappeared.

In the mean time, there are things you can do to rid your yard of these pests, if only temporarily.  We call it the Texas Two Step.  Fire ant workers go out and forage, then bring food back to the colony to feed the queen and babies.  The queen is deep in the colony and is protected by some pretty aggressive bouncers, so reaching her directly is hard.  However, you can spread broadcast bait in your yard and let the worker ants bring that back to the colony.  The queen eats it and it renders her sterile or kills her, depending on the bait.  In six to eight weeks, when all the workers have gotten old and died, the colony disappears.

Fire Ant Mound

photo by Bart Drees/Texas Agrilife Extension

Now, if you have a mound where it just has to go NOW, such as in your septic tank wiring, or by the mailbox, you can use a drench or powder directly on the mound.  This is more labor intensive and expensive, so isn’t practical if you have a lot of mounds.  It works very well on a few that just have to be gone yesterday.

People worry a lot about the environmental impact of pesticides, with good reason.  There are all sorts of stories of things you can put on a mound to kill it:  club soda, boiling water, and various other substances.  The scientists at the Texas Imported Fire Ant Research and Management Project have tried everything you can think of, and none of it works.  At best, the mound just moves over a few feet.  At worst, you waste time and money and risk getting stung.

Broadcast bait is fairly safe unless something eats a lot of it.  When spread correctly, it is put down at such a low rate that a bird, pet or child would have a hard time eating enough to make themselves sick.  Using a hand cranked fertilizer spreader, simply walk across your yard, cranking the spreader. Continue walking across the yard at a modest speed until you have covered the whole yard once.  That is it.  During the heat of the summer, put it out in the afternoon so it is fresh when the ants come out to forage at dusk.  When it is cooler, in the fall or spring, put it out in the morning so they get it as they are out foraging that day.  Drench or dust the mounds that are an urgent hazard.  Wait eight weeks and watch the mounds disappear.

You will have to repeat the treatment every year as the ants are bad about colonizing unused territory, but this should help you enjoy the outdoors this summer without dodging ants.  Make sure you follow the label directions, and enjoy stomping out ants with the Texas two step.
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{ 3 comments… read them below or add one }

Wendy July 11, 2010 at 6:43 pm

We went through a rough battle with fire ants just a few weeks ago. One of our dogs got bit several times so, that meant war.

I can’t use wide spread bait because of the dogs, neighbors cats, chipmunks, rabbits.. roam the yard. Our ant colony happened to be right next to the street so I could keep our dogs off of it with just keeping them on a short tie out when in that part of the yard.

I have tried almost everything there ever was for killing these mean hearted lil ants. So, this time I used diatomaceous earth. It is not a fast solution but, after 2 weeks, they are gone. It also involved me digging into the colony in a few places & making sure there was no water they could get to in the immediate area.

We live right next to a few hundred acres of desolate desert. The colonies are huge and wide spread. I just don’t understand why they can’t stay 30 feet over where no one would bother them.
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Fire Repair Service August 3, 2011 at 9:05 pm

why don’t you just let them live??


Stephanie Suesan Smith August 4, 2011 at 6:51 am

You don’t have fire ants where you are, do you? They are called that because they sting you and it hurts like fire. Lots of people are allergic to them and die from the stings. They damage lawn mowers, eat electrical wiring, destroy the nests of ground dwelling birds and small mammals, and are generally a menace. That is why we don’t just let them live.


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