What you can do about ants in your home


By the Contra Costa County Integrated Pest Management Advisory Committee

Where you see one ant you are bound to see more. Their small size allows them to easily enter your home. They crawl in through openings around water and electrical lines, and through cracks and crevices in the foundation.

Argentine ants are the main nuisance ant in the Bay Area. They don’t bite and they don’t carry disease, but they invade homes. Outdoors, they protect insects like aphids and scales from natural insect enemies. Their ability to create giant colonies makes them difficult to control.

The scouts, whose job it is to locate food for the colony, will search your home high and low for sugary drinks, fruit or other sweet foods, and meat. Adult ants feed only on liquids. One of their favorite foods is the “honeydew” produced by plant-feeding insects like aphids and scales. Adults collect solid food to feed to the young in the nest.

Use the Integrated Pest Management (IPM) methods below to prevent this pest from infesting your home.

Argentine Ant Identification

Argentine ants are ⅛ inch long and a shiny brown to black in color. They love the moist soil we create with our irrigation. They make shallow nests in the soil, under stones, logs, debris, concrete slabs, and often in potted plants. They make nests in wall voids, insulation, and cracks and crevices. They can even take up residence inside the overflow drain of a bathtub or sink, under carpets, and under piles of boxes. 

What You Can Do when Ants Are inside Your Home

  1. Spray ant trails with soapy water and then wipe them up.
  2. Clean up spilled food and drinks immediately.
  3. Keep food in the refrigerator or tightly sealed in metal, glass, or heavy plastic containers.
  4. Use caulk to seal cracks and crevices around the interior of the home.
  5. Apply gel bait at the entry points ants are using to get inside your home.

What You Can Do to Keep Ants away from Your Home

  1. Trim vegetation at least one foot away from the foundation to prevent access.
  2. Remove or treat aphid-infested plants and trees and pick ripened fruit to reduce food sources.
  3. Regularly clean the inside of garbage and recycling cans to remove residue that will attract ants.
  4. Use caulk to seal cracks and crevices around the exterior of the home.
  5. It is futile to try to kill all the ants outside your home, but where you see ant trails leading into the building, or find ant colonies that are close to the building, install exterior bait stations.

This article was written by Pestec IPM Provider staff in conjunction with the Contra Costa County IPM Advisory Committee. The County is dedicated to continually improving how pests are managed, and to using the least toxic and most cost-effective control measures. With its IPM Program, the County endeavors to lead by example.

For more information on the Contra Costa County IPM Program, please visit cchealth.org/ipm. For more information on ants, ask a Master Gardener! See http://ccmg.ucanr.edu/Ask_Us/


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