 to humans, unlike harvester ants or fire ants. However since there is little competition between opposing colonies of this species (one giant colony) this ant is the dominant species in areas where it becomes establish. It is very aggressive toward other species of ants and tends to out competes and replace other ants that are found in their same general area. As a result the Argentine ant is by a long way the major nuisance pest in urban areas, especially because of the availability of water. This ant exists in back yards at high densities associated with landscape features that provide favorable microclimates, such as potted plants and walkway bricks or stones. They enter homes through cracks and other spaces, in search of food or water.
Argentine ants are also an economic threat because of their potential to tend plant pest insects, such as mealybugs, scales, and aphids. In return for sweet honeydew secretions from these plant feeding insects, ants provide protection from natural enemies. Argentine ants may even move pests to better food sources or more favorable microclimates to maximize honeydew production. This mutualism can compromise management of pest insects by otherwise effective natural enemies, through removal or intimidation of predators and parasitoid wasps, leading to higher pest densities and greater plant damage than would occur in the absence of Argentine ants. For example, parasitism rates of an important citrus pest, the California red scale (Aonidiella auranti), were reduced two- to five-fold in the presence of Argentine ants.
Control. There are no known specific enemies of the Argentine ant. Therefore control is primarily via chemical and cultural means. Broadcast spraying of insecticides is of limited value because a substantial portion of Argentine ant colonies exist below ground where insecticides are unable to penetrate. Poison bait stations have proven effective at controlling Argentine ants in vineyards, though prolonged deployment may be required for natural enemy-mediated reduction