Citronella Ants

Facts, Identification & Control

Latin Name

Lasius interjectus

Appearance

What do they look like?
Workers are yellow and approximately 4 mm long. The queens are about 8 mm long. The workers have a strong lemon-like smell when crushed, which results in their name of citronella ant.

Citronella Ant
Citronella Ant image licensed under CC

How Did I Get Citronella Ants?

These pests do not build nests or breed inside homes. However, they do sometimes wander in through open doors and windows and swarm inside from soil that houses their colony. Often homeowners see swarming citronella ants in the basement and usually this swarm came from a colony that was living in the ground underneath the basement slab floor. Citronella ant swarmers develop wings and undergo a swarming stage like termites, which can bring them inside. The ants may also build their colonies in yards or near foundations.

How Serious Are Citronella Ants?

Repeated citronella ant swarms, which last for three or four days, are a nuisance for residents. Fortunately, the pests do not sting or cause damage. Because of their similar looks and behavior, these ants are easily mistaken for termites.

Signs of a Citronella Ant Infestation

Foraging workers and swarms of the winged reproductives are the most likely sign of citronella ant activity. Another possible sign can be earthen mounds generated when the ants nest in soil.

Behavior, Diet & Habits

Citronella ants nest in the soil. Outdoors, they nest under logs and rocks and landscape timbers. They also nest beside foundations and inside of crawlspaces. They make mounds of soil while they dig their galleries underground.

They often make their nests under slabs and porches. Sometimes they push soil up through a crack in a slab while they nest underneath. Homeowners sometimes mistake this soil as a sign of termite activity.

Inside homes, citronella ants nest in areas of high moisture. They often nest in wood that has already been damaged by fungus or termites. If citronella ants invade a home, it may be a sign that there is a moisture problem inside. Finding and solving the moisture problem is a priority.

Citronella ants feed on honeydew that they get from insects that feed on plant roots. Because of this, people seldom see the workers.

Reproduction

Inside the nest, a queen produces new workers and, periodically, winged males and females called swarmers. These winged individuals fly out of the nest and mate. The males perish soon afterward, while the mated females go on to be founding queens for new colonies.

Swarmers

Citronella ants often become a nuisance when the winged ants leave the colonies for their mating flight. Winged ants that emerge through a crack in a slab or a basement wall can be very distressing for the homeowners. These winged ants will not damage anything. A vacuum cleaner is the most effective way to remove them quickly.

More Information

The citronella ant gets its name from the lemon or citronella odor that people smell when they crush a worker. Some people call these ants “large yellow ants” because of their color. In some areas, people call them “moisture ants.” This may be because of the locations the ants choose for nesting. This ant is common from New England to the Pacific Northwest and southward to Florida and Mexico.

Removing potential nesting sites can help discourage citronella ants. Firewood should be stored off the ground. Firewood stacks should be as far from the home as possible.

If a homeowner is experiencing a citronella ant infestation, it is advisable to call a pest control professional.