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University of Minnesota Extension

Ground beetles

Quick facts

Ground beetles are one of the most common groups of beetles in North America.

  • They are found in many types of environments including forests, fields, shorelines and agriculture.
  • They are also found in landscapes and around homes, especially in August.
  • They may sometimes, become a nuisance inside buildings.
  • Outdoors, ground beetles are considered beneficial as they feed on other insects.

How to identify ground beetles

Pennsylvania ground beetle (actual size 5/8 inch)
Pedunculate ground beetle (actual size 3/4 inch)

Most ground beetles are small to moderate-sized insects.

  • About 1/8 to 1/2 inches long (a few can become as large as 1 inch in length).
  • They are generally flattened insects with obvious mandibles (jaws).
  • Most are black or brown and iridescent (show different colors in different angles of light).
  • Some species can be brightly colored, including blues, greens and reds.
  • The head is narrower than the neck and has moderate-length, thread-like antennae.
  • Ground beetles have long, slender legs.

Behavior and habits of ground beetles

  • Outdoors, ground beetles are considered beneficial as they feed on other insects.
  • Ground beetles are active at night and sometimes are attracted to lights.
  • They hide during the day and are found on the ground under leaves, logs, stones, loose bark and in grassy areas.
  • When exposed, ground beetles move quickly to find shelter but rarely fly.
  • Most ground beetles feed on other insects as well as other invertebrate animals.
  • You can find ground beetles during spring and summer and into the fall.
  • Ground beetles usually enter homes in mid and late summer.
  • They enter buildings through cracks, spaces and other small openings.
  • Inside, they can be found in hidden, damp areas in the basement or under boxes or other objects on the floor.
Vivid metallic ground beetle (Chlaenius spp.); 5/8 inches long

Ground beetles are not harmful

  • Ground beetles do not damage buildings, food or clothing.
  • They are not harmful to people.
  • If they are mishandled, they could pinch the skin.
  • They are just a nuisance when they are found indoors.
  • Ground beetles are short-lived indoors and do not reproduce there.

How to control ground beetles indoors

Only a small number of ground beetles are generally seen indoors.

  • You can remove them physically, e.g. capture them in a container or remove them with a vacuum.
  • You could also try setting out sticky traps, such as those used for cockroaches.
  • Place these traps in areas where ground beetles are most commonly found, especially along walls.

If you see a large number of ground beetles, you can reduce them using non-chemical steps:

  • Seal and repair potential entry points, such as cracks in the foundation, gaps and spaces around doors, ground-level windows and similar areas.
  • Thin out or remove wood mulch or other organic mulch that is directly adjacent to the foundation.
  • Stack firewood away from the home as far as is practical.
  • Remove stones, leaves, boards and other nearby debris.
  • Cut or remove tall grass and weeds around the home.
  • Minimize the use of lighting immediately next to the structure or switch the lights from bright white to yellow to minimize attracting ground beetles.

Using pesticides

False bombardier beetle (Galerita); 4/5 inches long

Pesticides are not necessary if only a few ground beetles are found indoors. When large numbers are getting inside buildings, a pesticide treatment around the exterior of homes is an option.

  • Apply a pesticide around the foundation to reduce the number of ground beetles that may enter buildings.
  • Common examples of active ingredients are bifenthrin, cyfluthrin, deltamethrin and permethrin.
  • These can be purchased as a ready-to-use liquid or as a ready-to-use granular.

CAUTION: Mention of a pesticide or use of a pesticide label is for educational purposes only. Always follow the pesticide label directions attached to the pesticide container you are using. Remember, the label is the law.

Authors: Jeffrey Hahn, former Extension entomologist and Stephen Kells, Extension entomologist

Reviewed in 2024

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