[Pest Profile] Pavement Ant

PAVEMENT ANT

Order/Family: Hymenoptera/Formicidae
Scientific Name: Tetramorium caespitum
(Linnaeus)

Description
Pavement ants are 1/16- to 1/8-inch long with a dark body and lighter colored legs. They have two small spines on the back portion of the thorax, two nodes in their petioles, and their bodies are covered with stiff hairs. Pavement ants are easily identified by the narrow, parallel grooves on their head and thorax.

Biology
Little is known about the biology of this species. The developmental time (egg to adult) is 36 to 63 days. Indoors, swarmers emerge anytime, and they emerge outdoors in June and July.

Habits
Pavement ants nest outdoors under flat stones, under sidewalks, along curbing, under concrete slabs, etc. They invade structures in search of food and are a particular problem where slab-on-grade construction is prevalent. Indoors, they nest within walls, insulation, floors and near heat sources during the winter. Pavement ants feed on insects, meats, seeds, and sweets, but prefer meats and greases. These slow-moving insects forage in trails as far as 30 feet from the nest. Although not particularly aggressive, workers can bite and sting.

Control
All cracks in exterior walls which provide access to voids or interior areas should be sealed, as should cracks in slabs and gaps in expansion joints. Debris on the ground where these ants nest should be removed. Pavement ants are attracted to and feed on sweet- and protein-based baits. Baits should be placed where trails have been established and where the ants have been sited. Unless using containerized baits indoors, baits should be inaccessible to children and pets. Baits should be checked often for feeding activity and availability. The most effective control is to follow ant trails to the nests and treat them with a residual insecticide. Exterior nests should be drenched with a liquid formulation. Particular attention should be paid to cracks and expansion joints in slabs, driveways, sidewalks, etc. Metal extension tubes should be used to inject liquid products directly into these sites. If subslab areas require treatment, the use of foam injection or liquid subslab treatments should be considered. Nests in wall voids are more easily treated by aerosol injection or application of a dust formulation. When the nests cannot be located, a barrier spray should be applied to foundations and the soil immediately adjacent to the building.