Large Yellow Ant/Citronella Ant

Publication Number 444-283, posted January 2003

Authors: Lois Swoboda, Graduate Student, Department of Entomology and Dini Miller, Extension Entomologist; Virginia Tech


Scientific Name

Hymenoptera: Formicidae, Acanthomyops interjectus (Mayr)

Size

1/4 " (4-6 mm)

Color

Workers are bright yellow. Winged reproductives are dark brown.


Interior view of a citronella ant colony.

Description

Large, attractive, bright yellow ants. All workers of this species are the same size. The winged reproductives are dark brown and 1/4 inch long. All members of the colony have a pleasant citrus smell when crushed. Citronella ants forage below the surface of the soil and are not seen on the soil surface under normal circumstances.

Habitat

The citronella ant nests in rotting wood, under slabs, patios, and rocks, in crawl spaces and between insulation and sub flooring. Workers in large colonies may create significant mounds of soil during the summer. In rare instances, numerous small mounds or visible openings may appear scattered throughout a lawn.


Citronella ant nest material composed of soil & plants.

Life Cycle

Like all ants, this species has a complex life cycle developing from eggs into white legless larvae and pupae before emerging as adults. Development of the young takes place entirely within the nest. Since workers forage underground or at night, it is rare to see any member of the colony other than the emerging reproductives. Swarms of reproductives occur from early spring through fall in Virginia. Swarming citronella ants nesting under heated structures often emerge very early in the season (March - June) at about the same time as swarms of subterranean termites.

Type of Damage

None. These ants are harmless. Swarming reproductives emerging from under structures may be a temporary nuisance or alarm homeowners because of their superficial resemblance to termite swarmers.


Workers tending larvae.

Control

Under normal circumstances control of this ant is not necessary.

Nonchemical
Reduce ant habitat by removing rotting wood and debris from cellars, outbuildings and yard. It may be desirable to create a debris free band about 3 feet wide around the house. All living plants and all refuse, including wood or pine needle mulch, should be removed from around the foundation.

Reproductives that emerge within a structure or crawl space will not survive because the interior habitat is not suitable for starting a new colony, so no control measures are necessary. Indoor swarms of reproductives may be removed with a vacuum cleaner.

Chemical
Baits are not effective for this ant. Should removal of a colony be necessary, locate the area of greatest ant activity by careful inspection. Pay special attention to refuse composed of paper or wood. Apply diatomaceous earth or silica gel to the entryway in accordance with the product label.

Interesting Facts

Several smaller species of Acanthomyops are found in the wild but rarely enter structures. These small yellow ants also produce a distinctive citronella odor when crushed. Pharaoh ants, an important structural pest, may be yellow in color but lack the characteristic citrus smell of the Acanthomyops.


Ant and termite swarmers. Notice the difference in the size & shape of the wings.
Illustration courtesy of the University of Nebraska-Lincoln Institute of Agriculture & Natural Resources.

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