Argentine Ant
Ants—Argentine
Size
Argentine ant workers are about 1/16 in (2.2-2.6 mm) long. Queens are about 1/8-1/4 in (4-6 mm) long.
Color
Light to dark brown
Where
Native to Argentina and Brazil, but probably brought to U.S. on coffee ships before 1891. Now found in southern U.S. and in California, with isolated infestations in Illinois, Maryland, Missouri, Oregon, Washington.
Habitat
Argentine ants build shallow nests near a source of moisture, such as along sidewalks, under rocks, between plants, near water pipes, potted plants.
Diet
Argentine ants follow regular trails, and are often found outside near insects such as aphids, that produce a honey-like secretion, called honeydew. They like sweets best, but also feed on oil, fats, meat.
Biology
Colonies have many queens, and hundreds, or up to several thousand, workers. The numbers change depending upon the time of year. Overwintering nests are formed by colonies joining together. Different colonies get along with each other, but Argentine ants are aggressive towards other ant species and usually get rid of them. Mating takes place in the nest, so winged reproductive females are not often seen. Development from egg to adult takes an average of 74 days.
Damage
Argentine ants are mainly a nuisance pest, but since they crawl over garbage, sewage, and carrion, they can transport disease organisms.
Invasion
Argentine ants come inside when the weather is very wet or very dry, and when they are short on honeydew.
Control
1. Locate the nest by following the ant trail back from the food source. Trails may be somewhat hidden if they run along the foundations of a structure or along the edges of concrete walks below the height of grass or groundcover. Pull back grass to inspect.
2. Treat the nest with a registered residual insecticide.
3. Other treatments include baiting, use of boric acid dust in voids of walls, and treating the area around the perimeter of the structure to create a barrier.
4. When using any pesticide, be sure it is registered for the target pest/location. Read entire label prior to use, observing all label directions, restrictions and precautions.