Millipedes are common arthropods that provide a valuable service by breaking down organic materials, such as dead leaves and grass clippings, to recycle nutrients into the environment. But they can also become a nuisance when they gather by the thousands on lawns and sidewalks during summer. Keep in mind that millipedes are different than centipedes; millipedes don’t have a painful bite. In fact, they don’t bite at all!
In warm weather, millipedes actively wander. They may gather in very large numbers as they move from their feeding sites in search of mates. In some instances, this can result in thousands near homes. Occasionally, they may wander indoors by mistake. Fortunately, these mass aggregations will go away on their own.
The first step in keeping them out of the house is to pest-proof your home by sealing all cracks and crevices in and around the foundation, doors, and windows. Doors should be fitted with tight door sweeps.
Next, remove mulch and fallen leaves from against the house where millipedes can find shelter. Try to reduce moisture and wet areas close to the house by diverting water from rain gutters and air conditioning units away from the house.
A barrier spray around the outside foundation of the home will help when used in combination with the other tactics.
Millipedes that accidently enter buildings will die in a short time as our homes are too dry to support them. Sweeping or vacuuming them up is the best option when you encounter them indoors.
Ric Bessin, Extension Entomologist