Pharaoh Ant

Description: Pharaoh ants are very small; workers are about 1/16 inch long. They range from yellow to light brown. The thorax lacks spines and the petiole has two nodes. These ants can be distinguished from thief ants because they have a three-segmented club at the end of antenna.

Biology: These ants do not swarm; females mate in the nest, and new colonies are formed by “budding”. This means part of the main colony moves en masse to a new location. There may be hundreds of thousands of ants in a colony. A female produces 350 to 400 eggs in her lifetime. The entire life cycle is completed in 38 to 45 days at room temperature. Indoors these ants develop year round. Workers live approximately ninte to ten weeks and queens live four to twelve months.

Habits: Pharaoh ants are widely distributed throughout the United States. They can nest outdoors and are at times a crop pest; they are major problems in homes and institutions, such as hospitals, hotels, prisons or apartment complexes. They nest in warm, hard-to-reach location in walls, subfloor areas, wall sockets, attics, cracks, crevices, behind baseboards and furniture.

Pharaoh ants eat dead or live insects but seem to prefer meats or greases. They also feed on sugar, fruit juices, jellies and cakes. These ants are an especially important pests in hospitals where they have been found infesting the dressings on patients’ wounds, feeding on secretions from new born infants, in IV tubes, etc.

Control: Because they nest in such a wide variety of locations within structures, Pharaoh ants are very difficult to control. Since they do not necessarily follow specific trails to food sources, they are difficult to trace to their nests; however, it is useful to look near sources of water and food.

A successful Pharaoh ant control program will involve intensive baiting using baits that contain insect growth regulators or slow acting and non-repellent toxicants. Baits should be placed in areas where ants are or are expected to be active. The more placements, the better. Baits must be placed in areas in accessible to children and pets. Baits should be placed behind outlets, switch plates, areas where wires pass through walls, in cracks and crevices. etc/ The baits should be placed along straight lines, such as the edge of baseboards, moldings, etc. In southern states where these ants are active outdoors, exterior baiting programs have eradicated infestations that extended into the structure. The bait should be checked for continued acceptance. If the ants are avoiding the bait, another bait formulation should be used. Baits should be replaced as necessary. Several follow-up visits may be needed each month until control is effected. Elimination of Pharaoh ants from a structure might require a year or more of vigilant baiting.

Residual applications of insecticides should not be used to control Pharaoh ants. These applications affect <5% of the workers in a colony, stress the colony and cause the colony to split, leading to colonization of new areas with very little reduction in the existing population. it is important that this is explained to customers who might feel compelled to take things into their own hands.