Where Argentine Ants Are Found
You will find Argentine Ants mostly in the southern United States, especially California.
It is generally understood that Argentine Ants may have entered the United States aboard ships carrying coffee or sugar from Argentina during the 1890s. They expanded from the coast throughout California and to the southern parts of the United States.
Argentine Ants find Fire Ants to be fierce competitors, and so Argentine Ant populations are not as numerous in the southeastern parts of the United States.
Since Fire Ants and other competitors are largely absent in California, this state has seen the Argentine Ant thrive in the temperate and damp coastal regions. Argentine Ants have killed and displaced native Ants, many of which are ten times larger in size.
You probably won't ever see a winged form of the Argentine Ant, because mating is usually accomplished in the nest, not in mating flights. Argentine Ants are aggressive, often eliminating other types of Ants in the same area. They also destroy and eat other household pests such as cockroaches and exposed termites.
However, they prefer sweet foods and are often found tending aphids or scale insects on plants, using them as a source of honeydew.
Their usual habitation is outside, but these Ants can present a problem when they come inside foraging for food. They rarely nest in walls of buildings, as some other Ants commonly do. They enter to forage and then exit, returning to the nest.
The wingless worker Ant (most commonly spotted), is light to dark brown, about 1/12–1/8-inch long. The antennae are strongly elbowed (12 segments) and there is a single node in front of the abdomen (the waist). Queens are 1/6–1/4-inch long.
Here are some things to look for when identifying Argentine Ants:
- Uniformly dull brown color
- Petiole (the node that separates the thorax from the abdomen) has one erect node
- Thorax (middle part supporting the legs) is uneven in shape when viewed from the side
- Musty odor emitted when Ant is crushed
Photo and ID text courtesy of UC IPM Online
The winged queens can produce fertile eggs for up to 10 years after mating once with a winged male. Another difference in this type of Ant compared to other Ants, is that several productive queens can share the same colony.
One or more of these productive queens may leave with some of the workers to form a new colony when it gets crowded (this is known as budding).
The grub-like larvae are fed and tended by the workers, pupate, and then emerge to join their sisters in the colony (worker Ants are all sterile females). The white eggs are laid in the summer, and the larvae emerge after about 28 days.
The larval stage may take from 11–60 days. The pupal period may last from 10–25 days or more. Development from egg to adult usually takes about two months, but may take up to 4–5 months.
During the summer months, highly mobile satellite nests are usually established close to food sources.
Argentine Ants can persist in conditions where other Ant species could not survive.
They like to nest in moist soil next to buildings or under them. They can be found near sidewalks or plants. They nest near water and food sources.
Foraging Ants will enter the house when outside conditions are extremely dry or wet.
Colonies are large, often containing hundreds of queens. The queens and larvae eat protein/grease foods (and baits) almost exclusively, while the workers eat sugar-based foods (and baits).
They are extremely mobile and will relocate colonies frequently. Argentine Ants can be easily tracked because they generate strong pheromone trails when foraging. In many areas, you will see pheromone trail super-highways three and four lanes wide.
Argentine Ant workers prefer sweet foods such as syrup, fruit juices or plant secretions, but will gather protein/grease-based foods to bring back to the queens and larvae. They gather food day and night. Of all the smaller sized Ants, this one prefers sweet more than protein.
Unless you use a non-repellent spray, baiting is the preferred treatment over typical residual spraying. Baiting is the most reliable way to eliminate the entire colony. When choosing Ant baits, it is best to choose from both the sugar-based baits and protein/grease-based baits. If using a spray, choose a non-repellent type unless you are treating the nest itself.
Argentine Ant Control Using Ant Bait
The use of residual sprays or dusts stress Ant colonies, causing them to split into sub-colonies and scatter. This scattering, also called budding, multiplies the number of Ant colonies, and thereby multiplies your Ant problem.
When you bait, use a slow-acting bait. Quick-kill insecticides and baits will only kill the foraging Ants, not allowing those worker Ants to take the bait back home to feed the queen, nest workers, and brood.
If the Ant bait that you are currently using is not effective (if the Ants are not visiting the bait) you will need to change the baits. Slow-acting baits provide a variety of the foods the Ants find in nature. Examples are: other insects (proteins/grease-based baits), nectar, aphid honeydew, and plant products (sugar and carbohydrates found in sweet-based baits).
Choosing a bait requires an understanding of the nutritional needs of the colony. To be sure that you have all the baiting needs met, you may want to be ready with a sugar/carbohydrate-based bait, a grease/fat-based bait, and a protein-based bait.
IMPORTANT NOTE: REMOVE ALL OTHER FOOD COMPETITION WHEN BAITING AND LEAVE THE BAIT ALONE ONCE THE ANTS START FEEDING ON IT.
An excellent article by the University of Florida Extension Service can be found at Ant Trails: Baiting. It gives an overview of management with baits.
Recommended Argentine Ant Baits
(Sweet and Protein/Grease Feeding Cycles)
When in doubt of which one to choose, choose one from each category.
- Top recommendation from the protein/grease category is Invict Blitz, followed by Invict Xpress, then Advance 375a.
- To recommendation from the sweet feeding category is Optigard Ant Bait Gel, followed by Advion Ant Bait Gel and then Intice Gelanimo.
Protein /Grease feeding cycles
Invict Blitz Granules (Sorry, only registered Fl, GA, LA and TX)
Sweet Feeding Cycles
Non-Repellents For Outside and Inside Argentine Ant Control
Spraying for Argentine Ants with Non-Repellents
You would spray on the outside with Taurus around the perimeter. Usually spraying the perimeter is enough treatment for Argentine Ants, as they will go outside. If you need any insecticide inside, use Phantom Aerosol in cracks and crevices.
Non-Repellent insecticides are best for ants and termites, because these insects can not detect it and will not try to escape the insecticide. Non-repellent insecticides can't be smelled, tasted, or even felt by Argentine Ants.
Another advantage for using a non repellent insecticide such as Taurus or Phantom for Argentine Ant Control, is that you can use a good mega ant colony bait , like Invict Blitz with it. Repellent insecticides do not combine well with insect baits, because they contaminate the lures inside the baits; that is not the case with non-repellents.