Millipedes vs Centipedes: Which Pest Invaded Your Home? 2026

In certain times of the year, especially after intense and prolonged rains that saturate the ground, pest control professionals receive calls about an invasion of "dark little worms climbing up exterior walls and trying to get inside. They curl up and, when disturbed, give off a sharp, unpleasant odor."

These aren't larvae at all—they're an invasion of millipedes, only distant relatives of insects. Millipedes and centipedes are not the same thing! Both belong to the Myriapoda group, but to two different classes: millipedes are Diplopoda, centipedes are Chilopoda.

It's not that hard to tell them apart with a trained eye. Millipedes, for example, have a generally round, cylindrical body and are equipped with many tiny ventral legs (up to more than one hundred pairs), two per segment. They typically live in moist soil, under stones and rotting wood, feeding on decomposing plant material, roots, even green leaves in contact with the ground, fallen fruit, and in special cases, animal droppings and invertebrate remains. When disturbed, they curl into a spiral and can produce repellent, foul-smelling substances through special body glands. Their habits are little known, and they go unnoticed because they are often nocturnal. High humidity is essential for their survival due to an extremely permeable cuticle. After internal fertilization, eggs are laid in a mass in the soil, sometimes in a kind of chamber prepared by the female. After hatching, the mobile larva has only three pairs of legs. During each molt (7–10 molts until adulthood), the number of legs and segments increases, varying by species. Sexual maturity is reached after 1–2 years, sometimes even after 4–5. In Italy, the most common species, difficult and complex to identify, are up to 4–5 cm long and belong to different orders: Julida, Polydesmida, Glomerida, Polyxenida.

Why Do Millipedes Invade Homes?

A characteristic of these soil animals, known worldwide, is their ability to migrate and form huge clusters of individuals. In urban environments, they are found on concrete walls, pillars, sidewalks, and the exterior walls of houses and warehouses. In Japan, up to 15,000 per square meter have been estimated! The reasons for these invasions are often unknown, although sometimes they are linked to adverse environmental conditions such as heavy rainfall, searching for a more favorable environment to overwinter or spend the summer, or local habitat modification. In any case, activity peaks occur in autumn and spring, sometimes even in summer.

Millipedes vs. Centipedes: Key Differences

• Body shape: Millipedes are cylindrical; centipedes are flattened.
• Legs per segment: Millipedes have two pairs per segment; centipedes have one pair per segment.
• Defense: Millipedes curl up and secrete foul-smelling liquid; centipedes are fast and can bite.
• Diet: Millipedes eat decaying plant matter; centipedes are predators of insects and spiders.
• Risk to humans: Millipedes are generally harmless; centipedes can deliver a painful but non-lethal bite.

How to Prevent Millipede Infestations

Since millipedes thrive in moisture, reducing humidity around your home is key. Seal cracks in foundations and walls, remove leaf litter and wood piles near the house, and ensure gutters drain away from the structure. If you're dealing with a severe infestation, you may need to consider chemical control. For outdoor perimeter treatments, some homeowners look into the best poison for raccoons and other pests, but millipedes require specific insecticides labeled for their control.

Natural and Chemical Control Methods

• Reduce moisture: Fix leaks, improve ventilation in crawl spaces.
• Remove hiding spots: Clear away mulch, stones, and compost piles from the foundation.
• Create a barrier: Apply diatomaceous earth or insecticidal dust along entry points.
• Use granular baits or sprays: Products containing bifenthrin or cyfluthrin are effective for perimeter treatments.

When to Call a Professional

If you see hundreds of millipedes inside your home, it's a sign of a large outdoor population. A pest control professional can assess the situation and apply targeted treatments. For related outdoor pest issues, check out our guide on yard and outdoors pest management or explore home and garden tips for keeping your property pest-free.

Frequently Asked Questions

Are millipedes dangerous?

No, millipedes are not dangerous to humans or pets. They do not bite or sting, but they can secrete a liquid that may cause skin irritation in some people.

Why do millipedes come inside after rain?

Heavy rain saturates the soil, forcing millipedes to seek drier ground. They often climb walls and enter homes through cracks and gaps in search of shelter.

How long do millipedes live?

Millipedes can live from 1 to 5 years depending on the species. They grow slowly, taking up to 2 years to reach adulthood.

Will millipedes infest my furniture or food?

No, millipedes feed on decaying organic matter, not fabric or stored food. They are simply seeking moisture and shelter indoors.

Can I use the same poison for millipedes as for raccoons?

No, raccoon poisons are not labeled for millipede control. Always use an insecticide specifically designed for millipedes. For raccoon issues, refer to the best poison for raccoons guide for safe and effective options.

Author: Paulo Vivere