House centipedes (Scutigera coleoptrera) are Mediterranean natives that thrive in humid environments. Although considered beneficial arthropods because they eat large amounts of pest insects, their strange appearance and furtive actions can make homeowners unwilling to share indoor space with the creatures. Several management options can help you get rid of house centipedes if they become a nuisance.
House centipedes have rounded heads, long antenna and flat, yellow-gray bodies that reach 1 to 2 inches in length. Each adult sports 15 pairs of 1/2-inch-long legs. The last pair of legs is about twice as long as the body and is used to "lasso" prey, particularly silverfish, termites, spiders and roaches. House centipedes pose no threat to pet or human health and won't damage any household goods, plants or food. They typically don't bite unless threatened, and their small, weak jaws have trouble penetrating skin. Centipedes aren't really insects, but rather distant relatives of shrimp and lobsters. Although they live on dry land, they still need very moist air to survive.
Because centipedes require moist environments, you'll most commonly find them in damp basements, cellars and bathrooms. Setting up dehumidifiers in moist areas can reduce air humidity enough to make house centipedes leave. Further reduce moisture levels by inspecting water pipes, faucets and HVAC units, fixing any drips or leaks that you find. Adjust lawn sprinklers so the water doesn't puddle around your home's foundation.
Get Rid of Outdoor Clutter
Eliminating potential outdoor hiding and breeding spots that lie close to your home's foundation can keep house centipedes from wandering indoors. Because house centipedes prefer moist shade provided by organic materials, this means cleaning up grass clippings, compost, rock, mulch, leaves and wood piles. If you must use mulch in a flowerbed that touches the foundation, regularly turn the material so it has a chance to dry out. Consider laying a band of gravel between the mulch and your house to keep the foundation dry.
Seal Entry Points
Centipedes frequently make their way inside homes by crawling beneath doors, slipping through window gaps or shimmying through small cracks in the foundation wall. Make sure your windows and doors fit snugly by caulking around the edges. Installing snug-fitting thresholds on all exterior doors can also keep house centipedes outdoors, especially if you caulk along the outside edges of the threshold. Make sure your window screens fit tightly and have no tears or little gaps. Use the appropriate filling material to repair cracks in the foundation wall.
Use Diatomaceous Earth
Diatomaceous earth is an inorganic pesticide that kills any insect that consumes or touches it within two days. Use a powder duster or hand duster to spread a thin, uniform layer of dust around baseboards and in the corners of rooms with high humidity levels. Dust cracks and crevices on the foundation wall and around exterior windows, doors and vent openings. Experts at the Missouri Botanical Garden recommend applying a 3-foot band of diatomaceous earth on the soil around your home's foundation. Diatomaceous earth remains effective as long as it stays dry. Replace the product as needed.
Diatomaceous earth can cause skin and eye irritation. Wear protective eyewear, rubber gloves and a dust mask to reduce your risk of exposure. Use the product only in areas where kids and pets don't wander.