The best way to choose a millipede pesticide is to look for products labeled as appropriate for millipede control in the area the homeowner is making the application, according to Clemson University. Pesticide sprays applied around walls and other entry points can help reduce millipede invasions. Use enough water to penetrate the ground when using an outdoor pesticide to ensure the pesticide reaches areas where the millipedes live.
For indoor treatment, apply the pesticide where millipedes hide most often, especially behind cracks, baseboards and spaces. In this case, select a pesticide labeled for indoor use. These pesticides are mostly available in ready-to-use liquid or aerosol forms.
When working outdoors, apply a liquid pesticide around the foundation of the building and adjacent areas to keep the millipedes at bay. The pesticide should be labeled appropriate for outdoor use around buildings. Pesticide treatment is less effective if there is shelter and food present around the foundation area. Apply an outdoor pesticide in late summer when millipedes are common indoors.
The use of pesticides offers only a short-term solution, and the emphasis should be on reducing access points and conditions favoring the invasion of millipedes, warns North Carolina State University. The most effective measure is to reduce hiding places and excessive moisture in and around the home.