Ask homeowners to name the pests that give them the most headaches, and near the top will likely be one pesky small insect that invades and colonizes their yard by the thousands.

Ants.

Gary Bachman, Mississippi State University
Gary Bachman, Mississippi State University

They move in with rows of marching soldiers carrying away your picnic and building dirt mounds marking the landscape of your lawn like hill forts. And no one says “hurrah” to fire ants, which can pack a powerful sting.

“You’re in your garden and you run into an ant hill, it’s not a happy time,” says Gary Bachman, Extension and Research Professor of Horticulture at Mississippi State University. “And in those cases, you really need to apply some kind of control measure.”

Those mounds can suffocate the grass underneath the dirt and the ants themselves can bite pets or kids just trying to enjoy the lawn.  If the infestation gets bad enough, you’ll have to launch an offensive of your own, and root out the invaders.

With fire ants especially, Bachman says in the whole scheme of things, they’re a nuisance.  “They’re going to create problems in turf areas and landscape bed areas that people are enjoying,” he says.

In those cases, it’s time to take some action.

First Step: Identify Your Ant Species

Knowing who you’re dealing with is key when trying to get them off your lawn, and it’s the first step to solving your ant problem.

Many species of ants take up residence in America’s lawns, writes Donald Lewis for the Iowa State University Extension.

Fortunately, many of those species don’t require any sort of control. They have a place in the ecosystem and a job to do.

Ants are social insects, living together in vast colonies. But it’s when those ants start to build mounds in your yard or invade your cupboards looking for dinner that they start to become a pest.

Across the Southern United States, though, fire ants that pack a fierce sting are another sort of pest altogether.

So figuring out just which ants are giving you problems is as important as it is tricky.

One common cause of confusion: Many people mistake flying ants for flying termites, and vice versa. The difference is in the wings. Termites’ wings are all of equal size, while ants have one pair larger than the other pair.

Bachman recommends reaching out to your local extension if you’re in doubt. They’ll also know the best ways to go about controlling that particular species.

Types of Ants

Luckily, the University of California Statewide Integrated Pest Management Program has an excellent ant identification key. Just catch one of the offending pests and compare it to the diagrams to find out what you’re dealing with.

It may be the most common ant pest in that state, the Argentine ant, or the largest of the bunch, the carpenter ant.

Other types of ants marked as pests include pavement ants, pharaoh ants, odorous house ants and two species of fire ants.

Once you find the species, UCIPM has quick management tips to help you control each type.

For example, to control carpenter ants it recommends trimming branches and limbs of trees and shrubs that touch your house. Find the damp, woody places where they nest and remove or treat them.

As for Argentine ants, keep your home clean and sponge the ant trails with water when you see them.

Plug up entry points with caulk or silicone where you see them coming in through crevices. Use ant baits to deal with the entire colony.

A Special Case: Fire Ants

Fire ants
Fire ants, which slipped into the U.S. in the 1930s, have spread throughout the South and are slowly taking their bad biting habits northward. Credit: Marufish. CC 2.0

One species, the imported red fire ant, causes the most pest problems of all. Not only do fire ants disrupt turf with mounds, they pack a sting that raises a white pustule and burns badly enough to give the species its name. And yes, fire ants really do sting all at once, or close to it. They like to climb vertical surfaces like, oh, say, your legs. When one senses danger, it emits a pheromone that signals its mates to bite.

The North Carolina State University Extension explains that fire ant nests can often go undetected until a heavy rainfall causes them to build up a mound to escape groundwater. As the colony grows, the ants will continue to build, especially beside concrete or in sunny areas for the extra warmth.

To control them, research has shown drenching mounds with a large volume of very hot water can significantly reduce their activity. Unfortunately, satellite mounds near the original can form in just a few days.

Texas’ Agrilife Extension Service recommends a two-step approach: A pesticide bait, followed by individual mound treatment.

Commercial pesticide baits are often made of corn grits and soybean oil, with a low-dose ant poison mixed in. It is low in toxicity for humans but ants carry it back to their mound. It’s about 80% effective but takes weeks or months to do its job. Step 2 is hitting the mounds with either a chemical pesticide or boiling water.

N.C. State offers a flow chart to help you decide which treatment is best. It factors in the volume of ants and the amount of foot traffic nearby to lead you to a treatment plan best for your yard.

DIY Ant Control

Controlling ants in your lawn is definitely a job you can tackle on a Saturday at home.

Bachman says it’s an easy job for a homeowner, with bags of ant killer running about $20 to cover a 5,000 square foot lawn.

For his small lawn, he says that’s enough to last the whole year.

And the professional pest control services will essentially do the same thing the DIYer at home would use to keep an ant-free lawn.

“They don’t have a better magic bullet,” Bachman says.

Pros will bring their expertise and economy of scale to the job, but calling in the professionals to kill ants is usually only necessary once they’ve migrated inside your home.

Dealing With Ant Mounds

But that doesn’t mean those mounds do nothing to your turf.

As ants build those mounds, they can smother those warm-season grasses that don’t tolerate shade well, Bachman says.

“Those fire ants can make some pretty impressive mounds,” he says. “I’m always amazed driving down the highway.”

You might end up with some spots in your lawn, but for the most part the ant mounds won’t kill the grass, he says.

In his article, Lewis writes that to avoid that mound damage, simply rake away the hill as you notice it.

You can also hit it with the garden hose and wash it away.

Applying Insecticide

If they’re too persistent for that, it’s time for the big gun: an insecticide. To apply:

  • Rake the mound flat spot treat the nests with an insecticide after you rake it flat.
  • Sprinkle the granules on the soil surface, or drench the surface with the diluted chemical solution. Rake again gently after application.
  • Make sure to read and carefully follow all manufacturer directions.
  • If using granules, irrigate immediately afterward to work the chemical into the soil.
  • Keep it away from unwary children or pets who may inadvertently stumble upon it.

Professionals can definitely treat ant infestations in your lawn, but Lewis notes that overall lawn treatments, such as spraying a fertilizer-insecticide combination across the entire lawn are seldom necessary.

Kicking Ants Out Permanently

The secret of success in controlling an ant infestation is locating and destroying the ant colony, says the Penn State Extension.

That includes killing the queen and her young.

Bachman, who also hosts the award-winning “Southern Gardening” TV program, recommends a broadcast bait application applied at intervals throughout the year across the entire lawn.

He uses holidays to mark application dates: Easter, Fourth of July and Labor Day. The application should keep the area clear of ants for about three months, he says.

Bachman applies the ant bait insecticide across his entire lawn.

Soil Drench, Powder, Granules, Baits

N.C. State offers some advice for how to get rid of ants yourself via soil drench, powder or granules, and baits, and the characteristics of each product type.

Soil drench:

  • Fast-acting, best applied in high-traffic areas with low tolerance for ant activity
  • Must apply with at least two gallons per mount to reach the queen in the nest
  • Best applied mid-morning when ants are closest to the surface
  • Do not physically disturb the mound before or after application

Powder/Granules:

  • Apply to the top of the mound and follow up with irrigation
  • Make sure irrigation is significant enough for the active ingredient to reach the queen

Baits:

  • Slow acting, may take three days or up to two weeks
  • Do not place bait stations on top of the mound, but within a two-foot radius around the mound
  • The product must be fresh and kept dry

Bachman doesn’t recommend the home remedy of using instant grits as ant bait and killer. Folks think the ants eat the grits and the grits then expand inside the ant and kill it.

But worker ants don’t eat solid food, he explains. They give the food to other ants still developing inside the nest, who vomit up liquid food that other ants then eat.

So using instant grits is essentially feeding the ants.

The insecticides that Bachman recommends using are carbohydrates with the poison attached. That means when those other ants vomit up the food, it contains that insecticide that then kills the ants.

Facts About Fire Ants

We have Australia-based professional pest exterminator Alexander Crawler to share the following facts:

  • Fire ants have been imported to the USA thanks to an unfortunate incident. A cargo vessel from South America. 
  • Soil further North makes it hard for ants to survive, thus the species prosper in warmer lands.
  • The average fire ant colony topples 200 000 in the count.
  • Male ants are rarely part of the colony, although not unseen. 
  • Fire ants can build tunnels spreading over 25 feet away from the colony.
  • The life of a fire ant consists of 4 stages – eggs, larvae, pupae, and adults.
  • It can take anywhere between 3 and 6 months for a colony to become big enough for you to spot.

Calling in Professional Pest Control for Ants

Sound like a lot? If the infestation is too much to knock out on your own, call in the pros.

For most homes, a professional exterminator can treat ants one time for between $150 and $300, according to Angie’s List.

Some companies also offer annual pest management contracts with regular treatments costing between $300 and $700. That total covers several treatments, as most single-family homes don’t usually need monthly treatments to get rid of ants.

Unfortunately, knocking out one colony or one infestation of your yard isn’t going to keep the next troop of ants from discovering your lawn anew.

But any way you go about it, keeping ants from colonizing your yard will mean a healthy green turf that anybody can enjoy without the risk of getting bit.

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