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How to Kill Coastal Brown Ants

By Damien Campbell ; Updated September 21, 2017

Coastal brown ants -- Pheidole megacephala or bigheaded ants -- are invasive insects that are difficult to control. Worker ants are light yellow to brown in color and are easily identified by their conspicuously large heads relative to their bodies. Brown ants construct large underground nests, which may damage garden plants, and workers often find their way into homes searching for food. In addition, brown ants feed on honeydew produced by aphids and other garden pests and will protect these pests from other insects.

Remove ants from your home. Clean all observed trails with soap and water. Ants navigate to food sources via chemical trails. By wiping away the scent, you will clear away their known path. If you have coastal ants on your property they likely will find a new way into your home.

Apply permethrin wettable powder insecticide in areas of your home where you have seen ants entering. Permethrin kills on contact and is safe for indoor use. The treatment will last for 10 to 12 weeks, after which reapplication is required.

Treat outdoor areas with a granular ant bait. Ant baits contain slow-acting insecticides that the worker ants carry back to the nest, increasing the chances of killing the queen and disabling the colony. Place bait in dry areas where ants are known to forage.

Monitor your lawn carefully for coastal brown ants. Reapply ant baits as needed. Coastal brown ants may have several nests on your property, and populations can rebound rapidly. Several treatments of insecticide may be necessary to remove these ants from your property.


Things You Will Need

  • Permethrin wettable powder
  • Granular ant bait
  • Soap
  • Bucket
  • Wash cloth


  • Follow application instructions on insectide labels.