The name of this ant possibly arises from the mistaken tradition that it was one of the plagues of ancient Egypt. This ant, which is probably a native of Africa, is now distributed worldwide; it is one of the more common household ants in the Kansas City area and is the most difficult household ant to control.
The Pharaoh ant has the ability to survive most conventional household pest control treatments and to establish colonies throughout a building. More than just the food it consumes or spoils, this ant is considered a serious pest simply due to its ability for "getting into things." It has become a major pest of residences, commercial bakeries, factories, office buildings, apartments, and hospitals or other areas where food is handled. In ant-infested hospitals, burn victims and newborns are subjected to increased risk because the Pharaoh ant can transmit over a dozen pathogenic pathogens. Pharaoh ants have been observed seeking moisture from the mouths of sleeping infants and from in-use IV bottles.
The workers of the Pharaoh ant, Monomorium pharaonis (L.) are monomorphic (same size), but vary slightly in length and are approximately 1/12” long. Their antennae have 12 segments with a 3-segmented club. The head, thorax, and petiole have dense but small punctures. The body color ranges from yellowish or light brown to red, with the abdomen often darker to blackish. A stinger is present but rarely used.
Control of Pharaoh ants is difficult, due to their nesting in inaccessible areas. Another reason for difficulty is that colonies have multiple queens. Treatment must be thorough and complete at all nesting sites, as well as the foraging area. Thus, treatment must include walls, ceilings, floor voids, and electrical wall outlets. Baits are now the preferred method of control for Pharaoh ants and several baits (insecticides) are labeled for indoor ant control. A Pharaoh ant infestation of a multifamily building requires treatment of the entire building to control the infestation. Ants nesting on the outside may be controlled by also using a perimeter barrier treatment.
Baits cannot be placed in just any location and be expected to work. Pharaoh ant trails and their resources (both food and water) must be located for proper placement of baits and effective control. Non-repellent baits (such as boric acid, hydramethylon or sulfonamide) should be used, as repellent baits can worsen the situation by causing the colony to fracture and bud. As a result, ant activity will briefly diminish as the new colonies establish themselves, then again become a problem as the foragers resume activity.