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
Most ground beetles are small to moderate sized insects.
- About 1/8 - 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
Ground beetles are active at night and are occasionally 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.
Are ground beetles harmful?
Only a few ground beetles are found in buildings at any given time. There are times when large numbers can enter structures.
- 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 get rid of ground beetles indoors
Small number of ground beetles
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.
Large number of ground beetles
If you see a large number of ground beetles, you can reduce their numbers through a number of 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.
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.
Reviewed in 2018