You can put up all the “no trespassing” signs you want, but if your house has cracks, crevices, and reliable food sources, the only message Argentine ants will receive is, “Come on in.” (Plus, ants can’t read signs anyway.) Curb an invasion of these unwanted visitors with the following tips on how to get rid of Argentine ants.
Especially difficult to kill off due to their propensity for displacing other ant species and merging with other Argentine ant populations to form super colonies, the best you can do is control them through methods of exclusion, habitat modification, ant baits, and insecticides. But first, make sure the insects you’re dealing with are truly Argentine ants.
What are Argentine ants?
Argentine ants were introduced to the U.S. by way of Brazil and Argentina (hence the name). Scientifically referred to as linephithema humile, they were first discovered in California during the early 1900s. These ants live in large colonies with multiple nests of thousands of female workers, multiple queens, several hundred reproductive ants, and their larvae.
While Argentine ants are aggressive toward every other ant species, so much so that they’ll drive total populations of native ants from an area, they’re quick to buddy up with other Argentine ants to form super colonies. And a super colony can hold large numbers of these insects — around a billion or so.
Identification
Sometimes mistaken for odorous house ants (as they both can be dark brown in color, have one node on their waist, are super tiny, have a pair of 12-segmented antennae, and give off a smell when crushed), Argentine ants:
- Come in all shades of brown, not just dark
- Don’t have stingers, but they can bite (although not painfully)
- Have workers about 1/16 of an inch long and queens that can be twice that length
- Smell musty when crushed, compared to the rotten coconut smell of the odorous house ant
Reproduction
The main purpose of the hundreds of queens present in a colony is to lay eggs, typically resulting in thousands of offspring per mating season. But besides that, Argentine ant queens also take part in raising their young, unlike other ant species.
Living fairly long lives (with the exception of male reproductive ants, which die soon after mating), Argentine ants have time to continuously grow their communities. Here’s how:
- Rather than swarming, even though reproductive ants have wings, mating is done inside the nest to prevent possible run-ins with predators or bad weather.
- Known as “budding,” queens will recruit a group of worker ants to leave one colony and form another in a separate location. Some other species of ants reproduce via budding, too, but unlike those, Argentine ants tend to build new nests super close to other ones, essentially forming super colonies. These super colonies will share workers and can stretch for several miles.
Nesting
Nesting usually takes place outdoors, underneath wood piles, bricks, mulch, and concrete slabs and inside tree crevices, birds’ nests, and beehives. There, they’ll eat insect-produced honeydew, as well as eggs, waste, and other insects.
If weather or another environmental situation disrupts their outdoor habitat, Argentine ants may seek refuge inside your home through voids in your foundation or other entry points. This is especially true if foraging ants find food sources there. Like other types of ants, Argentine ants eat just about anything (from sweets and meats to fats and oils), and lay a pheromone trail along the route toward the food, so other workers know where it is.
How to get rid of Argentine ants
Let’s take a look at how to stop an invasion that’s already happened.
Wipe away ant trails
With soap and water, use a sponge or cloth to quickly wipe up any ant trails you see. This will remove some ants from your home immediately, as well as inhibit other ants from picking up on the pheromone trail to food.
Set ant baits
While baits are the most preferred method of evicting this invasive species from the home, it’s important to place the baits correctly for them to work. Only set baits where you have seen ant trails.
You can opt for ant gel, liquid baits, or bait stations, each of which work by posing as a sweet food source for the ants. Instead of food though, the baits are filled with slow-acting active ingredients like fipronil, orthoboric acid, or abamectin. Ants will take the “food” back to their nest, share it with the colony, and consequently, start to die off.
Note: Sometimes, these ants will catch on that the baits contain poison and will switch up their route and avoid partaking. Fix this issue by changing out the type of baits, as well as the locations where you set the baits, while still keeping them along ant trails.
How to prevent Argentine ants
Familiarizing yourself with their eating habits and nesting preferences will aid in your quest to keep Argentine ants out of your home because once they’re established in a location, it will be extra hard to get them out.
Argentine ants have outdoor nests typically, but if lured inside by the promise of food, they may also nest in:
- Moist areas like cracks in bathrooms
- Wall voids
- Crevices in wood flooring/baseboards
Here’s how to keep them out:
Exclusion
Caulk all gaps you can find around entry points, and if necessary, replace worn weatherstripping or install all new windows and doors. You can further restrict access by trimming back trees and bushes with branches close enough to entry points on your house.
Sanitize surfaces
Disinfect your home by eliminating potential food sources, such as spills, crumbs, and overflowing trash. Also be sure to put away leftovers and store dried goods in sealed containers. Have pets? Monitor those food bowls for signs of ants, and if necessary, put away any uneaten food until the next mealtime.
Limit honeydew-producing insects
Trading food for protection, honeydew-producing insects like aphids, whiteflies, scales, mealybugs, and psyllids supply Argentine ants with the sweet substance for their food. In exchange, the ants will defend those particular insects from predators, such as parasitic wasps and lady beetles. Inspect your plants (outside and in) and rinse away any bugs and the honeydew they leave behind with water.
Not only will this help reduce the number of Argentine ants near your home, but it will also help save your plants from damage.
Remove yard debris
Another form of habitat modification, clearing your yard of excess mulch, wood piles, and leaves takes away some of the Argentine ant’s favorite nesting sites. The less hospitable locations to build colonies, the more likely they are to scout other places — farther away from your house — to create new nests.
Any mulch you use for gardening should be kept away from your foundation and other entry points. If Argentine ants are dominant where you live, consider alternatives to organic mulch like landscape rocks.
Apply residual insecticide around home perimeter
Rather than a broad-spectrum yard spray (which can miss its target, as Argentine ant nests can go underground), a barrier spray specifically formulated for Argentine ants can help prevent their entry. These non-repellent, residual sprays should be applied 3 feet up the side of your home and 10 feet from your home’s foundation all around the perimeter. Since they are residual, these sprays can keep working for up to three months.
Note: Always read and follow the product’s instructions on the label.
Signs of an Argentine ant infestation
You’ll know you have an Argentine ant infestation if you notice lines of tiny, light to dark brown ants streaming along your floors, walls, countertops, and even inside appliances and cabinets. Large numbers of these ants can also be found moving up trees and along outdoor walkways.
These ant trails are made up of female worker ants, which are foraging for food. Once they find food, they’ll communicate that information back to the rest of their massive colony by leaving a trail of pheromones.
What causes Argentine ants?
A combination of weather, habitat disruption, and human behavior can lead to an infestation of Argentine ants. When the weather cools, for instance, these ants may be drawn to moist, warm bathrooms, basements, and laundry rooms. And if they find food there (think spills, crumbs, and unstored leftovers), they’ll let their fellow workers know where to find it, too.
FAQ about Argentine ants
Argentine ants don’t directly harm humans; they have no stinger, and their bite is painless. They can, however, cause harm to beneficial insects, such as pollinators, by aggressively driving them out of the area.
These ants can also indirectly damage plants by allowing aphids, mealybugs, whiteflies, and other honeydew-producing insects to feed on houseplants, shrubbery, and the like.
Short answer: No. For one thing, Argentine worker ants are all the same size, while fire ants can vary in size. While it’s true fire ants can be brown in color, they can also be red. What’s more, unlike Argentine ants, fire ants have a stinger, which can directly harm humans. People can have a bad reaction to a sting, or the sting can become infected, causing other illnesses.
When to hire a professional
An Argentine ant infestation is no joke, especially with their ability to quickly reproduce and spread. If the combination of DIY methods listed here isn’t making an impact, call in reinforcements. A local pest control pro can locate and treat nesting sites, seal up entryways, and employ the appropriate insecticide spray and baits.
Need to clear the yard of any debris that might attract ants? Connect with a local lawn care pro who can rake the leaves and gather up plant debris.
Main Image Credit: Heather Broccard-Bell | Canva Pro | License
