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Yellow Ants

Facts, Identification & Control

General Facts

Also known as citronella ants, yellow ants are named for the lemony scent they emit when alarmed or crushed. Distributed throughout North America, the pests are most common in the Eastern United States. Two species in particular are prominent nuisance pests: the larger yellow ant, or Lasius interjectus, and the smaller yellow ant, or Lasius claviger. Yellow ants are a subterranean species and are not reliant on the presence of humans for food, which means they pose few problems for homeowners.


Yellow ant workers grow to be anywhere between 3 and 4.5 mm in size. Swarmers have wings and are typically slightly larger than workers of the same species. Despite their name, yellow ants are not traditionally solid yellow in colour; instead, the insects generally appear reddish-yellow to reddish-brown. When crushed or disturbed, worker emit a distinctive and strong lemon-like odour.


As subterranean creatures, yellow ants nest underground, preferably in moist soil. Common nesting sites include open woods, pastures, fields, gardens, lawns, and locations next to house foundations, beneath concrete slabs or large rocks, and in rotting logs.


With no recorded evidence of yellow ants foraging for human food items, it is thought that the insects feed almost exclusively on the honeydew of subterranean plant-sucking insects. In fact, researchers who study the species believe the ants tend aphids in the same way dairy farmers tend cows.

Life Cycle/Reproduction

Since the colonies remain under ground, little is known about the inner-workings or reproductive habits of yellow ants. The pests produce winged alates in the early spring. In mid to late summer, winged yellow ants are often mistaken for termites when they start swarming. Pairs of males and females fly off in search of suitable locations to start new colonies. The fertilized females then shed their wings, overwinter, and become the queens of their newly established nests.

Problems Caused by Yellow Ants

Relative to other species of ants, yellow ants are of little concern as a pest. While the insects frequently establish colonies close to homes to take advantage of the heated soil, the individual ants will not live inside the structure. The pests also do not carry diseases, pilfer food supplies, or affect the structural integrity of buildings. Nonetheless, people may be alarmed and disturbed by the presence of the winged alates.

Detection/Signs of Infestation

Yellow ants typically leave mounds of soil around their nest openings. Finding these mounds and openings close to building foundations, in gardens or lawns, or under yard debris points to a yellow ant infestation. The sighting of swarming alates also means that an established colony of yellow ants is probably somewhere nearby.

Prevention Tips

To keep yellow ant workers and swarmers out of the house, residents should locate and remedy cracks in the foundation, broken window and door screens, and other potential entry points. Additionally, homeowners should keep lawns clear of debris and make sure drainage flows properly away from the house rather than soaking into the soil around the structure.


Due to the yellow ant’s classification as a low-threat nuisance pest, it is typically recommended that homeowners leave the insects and their nests alone. If alates get in the home, vacuuming up the winged ants is an effective and non-intrusive means of control. However, if the surrounding colony swarms more than once a year, residents of the affected property should consider contacting a pest control specialist for professional removal.

Get Rid of Yellow Ants