Ground beetles are one of the most common groups of beetles in North America. Adults vary in size from less than 1/8 inch to over one inch long. They are usually dark and shiny, although some species can be brightly colored. They are generally flattened insects with prominent jaws. Many ground beetles are active at night; some species are attracted to lights. In the daytime, they are found under leaves, stones, and other debris found on the ground. They are fast runners and often are found moving quickly along the ground. The larvae, which are worm-like, occur in the same site as adults. Nearly all adults and larvae are predaceous on other insects and are considered beneficial.

Calosoma species (Actual size: up to 35 mm.)

Pterostichus species (Actual size: 7-24 mm.)

Amara species (Actual size: 5-12 mm.)

Ground beetles are most common entering homes in mid and late summer. They enter buildings through cracks, spaces and other small openings. Once inside, they are sometimes found in hidden, moist areas in the basement or under boxes or other objects on the floor. Their presence indoors is incidental as they do not reproduce inside. Physical removal is the only control that is necessary for an occasional ground beetle.

Large numbers of ground beetles can be controlled by caulking and repairing potential entry points, such as cracks in the foundation, gaps and spaces around doors, ground level windows and other similar areas. Firewood should be stacked as far as is practical from the home. Stones, leaves, boards, and other nearby debris should be removed. Tall grass and weeds around the home should be kept cut. Change outside lighting to yellow lights to minimize attracting ground beetles. Inside the home, a cleanup of boxes, cases, papers, and other objects on the floor helps control ground beetles.

An outdoor application of an insecticide around the foundation temporarily helps to prevent these beetles from entering buildings. Common examples include bifenthrin, cyfluthrin, deltamethrin, and permethrin. Read all label directions carefully before buying insecticides and again before applying them. Information on the label should be used as the final authority.

E604G
Revised 10/02