How to Bug Proof Your Home from Ants

Pest Management In and Around Structures September 10, 2015 Print Friendly and PDF


Several ant species may be found in or around the home. They enter houses in search of food in the early spring through late fall when their normal food is not readily available outside. Usually their presence is merely annoying but there are certain species that are undeniably problematic.

Preventing Ant Infestations

  • Practice good sanitation methods.
  • Store food in airtight containers.
  • All cracks and openings into buildings should be sealed as completely as possible.
  • Check the seal or caulking around air conditioning units, windows, doors, pipes or other openings into the home.
  • Repair cracks and holes in floors, walls and ceilings. Seal openings around plumbing fixtures, furnace flues, electrical outlets, windowsills and walls, and along baseboards and ceiling moldings.
  • Thresholds on doors should be as tight as possible and cracks in porches and stoops should be sealed.
  • Remove moisture sources.
  • Roof leaks and plumbing leaks must be repaired.
  • Tree limbs must be clipped back and vegetation touching the roof or side of the house removed. Also, keep shrubbery away from air vents.
  • Wood-to-ground contact should be eliminated.
  • Firewood must be stacked away from the foundation and elevated off the ground.
  • Soil or mulch should not be placed up against the wood siding of a home.
  • Ant baits can be used as a deterrent, though it is important to note that many ants have different food preferences during the season.
  • An ant bait high in protein in the spring, and one high in carbohydrates for summer and fall will be most effective.
  • However, many baits are species specific so identification is critical.
  • General surveillance of the yard and house is important.
  • Inside inspect the edge of carpets and along walls and baseboards.
  • Examine areas near water sources since ants will move indoors in search of water.
  • Outside look around vegetation, along lawn and sidewalk edges and under mulch.
  • When foraging ants are found, try to trail them back to their colony location.
  • Instruct members of the family on identifying and avoiding fire ants.
  • The best way to control carpenter ants is to locate and directly destroy the nest. Otherwise, the colony can quickly infest your home.
  • Feed pets using pet tables.


Species Specific Information

The Imported Fire Ant

Imported Fire Ant Mound (Solenopsis invicta )

Imported fire ants are ant species in the genus Solenopsis that can cause serious medical, economic and ecologic problems. They are called imported fire ants because they are native to South America.

The two species of imported fire ants (red imported fire ant, Solenopsis invicta Buren, and black imported fire ant, Solenopsis richteri Forel) and their hybrid are invasive insects whose stings can cause serious medical problems. Imported fire ants interfere with outdoor activities and harm wildlife throughout the southern United States and elsewhere. Ant mounds are unsightly and may reduce land values. Although fire ants do prey on flea larvae, chinch bugs, cockroach eggs, ticks, and other pests, the problems they cause usually outweigh any benefits in urban areas. While it may not be possible to eradicate fire ants, controlling them is highly desirable. The best control programs use a combination of non-chemical and chemical methods that are effective, economical, and least harmful to the environment.

This information and much more information on the imported fire ant can be found at: ants

The Southern Fire Ant

The southern fire ant is commonly found around homes in the Southwest. Fire ants do not usually pose a threat to healthy adults, though they can be dangerous for the young, elderly and the infirm.

Fire ants sometimes nest indoors in wall voids. Bath traps, shower stalls, and hot water heater walls are particularly well-suited areas for fire ants. When fire ants are a problem what is the best solution? The key to fire ant control is to locate all mounds and destroy them. Mounds can be treated by using appropriate fire ant specific baits.


Thief Ants

Thief ants(Solenopsis molesta) are closely related to the southern fire ant. The thief ant takes its name from their habit of nesting close to, and in some cases inside the nests of other ants, from which they steal food. Thief ant colonies are found both indoor and outdoors. Nests are large and often have tiny tunnels connecting to the nearby nests of larger ants from which they habitually steal food and brood. Outside they can be located under rocks, around walkways and house foundations, in rotting wood and exposed soil. Indoor nests are found in any small crevice, particularly woodwork and masonry, under floors and behind baseboards.

These ants are prevalent in households, in which they forage for foods with a high protein content such as grease, cheese, meat and hollowed out seeds for the oil content. It is important to note that due to their small size, they can easily enter packaged foods. Unlike most other ants, they do not appear to feed on sweets. They travel great distances in search of food, and once a source is located, they form a trail of ants from the food to the nest.


Carpenter Ants

Carpenter ants (Camponotus spp.) are also problematic to humans. Although they are an important element in nature by enhancing the decay of dead wood, they are structural pests to homeowners. As a result, millions of dollars are spent annually in the United States controlling them.

The black carpenter ant (C. modoc) is most common in the east and Camponotus pennsylvanicus is a common western species. These are the two most thoroughly studied species in the United States. Species of carpenter ants in western states that are either structurally damaging or nuisance pests include: Camponotus modoc, C. vicinus, C. herculeanus, C. noveboracensis, and C. essigi. Other species of carpenter ant are distributed throughout the country.

Carpenter ants prefer moist softened wood and colonies are often established within buildings in areas where water leakage occurs. This may be areas such as porch pillars, around bathtubs, sinks, roof leaks, poorly flashed chimneys and poorly sealed windows and doorframes. If an initial colony of carpenter ants is first established outside within 300 feet of a building, satellite colonies may then be formed inside the building. It is therefore important to take note of what is happening outside before they come in. Look for the initial outside nest in decayed wood, such as dead trees, stumps, logs or decorative landscape wood. Once established, the ants may eventually extend their tunneling into sound wood. If a carpenter ant colony has been identified in the yard, take steps to remove it before it migrates into the home. When carpenter ants are spotted inside dwellings, it does not mean that a colony has also been established inside the house, they may be simply foraging for food. This is called non-seasonal foraging. Outdoor colonies typically forage during the spring and summer only.


Pyramid Ants

Pyramid ants (Conomyrma spp.) do not nest inside structures; instead, shallow nests are dug in soil and found in dry, open, sunny areas. There is one entrance surrounding which is a raised circular area, usually 5 to 10 cm in diameter. This is constructed of soil excavated from inside the nest chambers. Pyramid ants rarely enter or become pests in buildings, and infestations are generally the result of foraging workers entering in search of food. The ants do not possess a sting and are considered harmless. This ant is named after the pyramid shaped projection on the top of its thorax. There are two important species, the simple pyramid ant (C. insana) and the bicolored pyramid ant (C. bicolor). Neither species bears a stinger, instead when alarmed they produce an odor, like rotten coconut to deter predators. C. insana is about 1.5-2 mm in length. Their head and thorax can be light brown, dark brown or reddish black, their abdomen is darker in color. The bicolored pyramid ant (C. bicolor) is slightly larger, 2-3 mm in length. Their head and thorax is a distinctive red color and the abdomen is black, hence their name bi-colored Pyramid ants will feed on a variety of foods including other insects. Although they are carnivorous and predacious, they have a preference for sweets, particularly honeydew of sap-sucking insects such as aphids, mealybugs, leafhoppers and whiteflies. The ants will tend to these insects and protect them. When foraging the workers move quickly in strong, easily detected trails.

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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.