White-Footed Ant, Technomyrmex difficilis

Characteristics:

  • Black in color with pale yellow coloring of the tarsi at the end of the legs.
  • Body more than 1/8 inch (monomorphic)
  • Single flattened node between the thorax and abdominal gaster
  • Node is hidden from view by the gaster

White-footed ants form huge colonies containing multiple queens that may have hundreds of thousands of workers. The worker caste contains many individuals that are inter-castes that have characteristics of both queens and workers. These inter-castes can produce eggs and aid in colony reproduction. These fertile individuals make up about half the colony mass. Connecting satellite colonies are formed and contain millions of individuals. Winged females are formed in large numbers and emerge from late May to mid June and mate with wingless male nest mates. The mated females then start new colonies. The formation of new colonies also occurs by budding, when queens along with a number of workers move from the parent colony to a suitable nesting site. In these new colonies, queens may ultimately be replaced with inter-caste workers.

Distribution

The white-footed ant, Technomyrmex albipes (Fr. Smith), is currently found in South Florida, Hawaii and San Francisco and is expected to be moved throughout the world by human commerce. They are similar in appearance to the odorous house antTapinoma sessile (Say). They are slightly larger, more than 1/8 inch long, with a single flattened node (petiole) on the pedicel that is hidden from view by the gaster. The key identifying characteristic is the pale yellow coloring of the tarsi at the end of the legs. They are considered the most difficult structure-infesting ant to control.

Management

Outside, ants trailing on sidewalks, foundations and the sides of buildings are usually quite visible. Workers, laden with food or water, can be seen returning to colony nests. These trailing ants can be followed to the nesting site or where they enter structures. Foragers follow structural guidelines, maintaining contact with sidewalk edges, edges of patio slabs and ledges. They will find entry to structures by way of limbs and trees that contact the walls or roof. These ants can be found in piled items and in damp, shaded areas. Inside, the ants will nest in wall voids and in potted plants. They forage along the baseboards and the upper and lower surfaces of carpets.

Branches that come in contact with buildings should be removed. Seal all cracks in exterior walls and make the area less attractive to ants by removing mulch and vegetation from the foundation. Correct any conditions contributing to the infestation. Locate and treat existing colonies with a residual liquid insecticide to prevent ants from entering the structure.

Injecting an appropriate aerosol or dust insecticide through small drilled holes can treat ant colonies within wall voids. Aerosol applications are required for insulated walls. Treatment behind brick and stone veneer can be accomplished by applying a residual dust insecticide through 1/4 inch holes drilled every 4 to 6 feet through mortar joints using a hand-operated duster or a suitable electric duster. A perimeter treatment with a residual liquid spray is a primary control technique used to provide temporary relief from ant sightings. All existing colonies must be treated. Drenches of appropriately labeled residual insecticides are effective for colonies in the soil, and dusts and aerosols are effective for those colonies in wall voids.