Centipedes, Millipedes, Sowbugs & Pillbugs: Identification, Prevention & Control

Looking for ways to get rid of centipedes, millipedes, sowbugs, or pillbugs in your home? These common household arthropods may be unsightly, but they're usually harmless. Learn how to identify, prevent, and eliminate these pests using natural and effective pest control methods.

🕷 What Are Centipedes, Millipedes, Sowbugs & Pillbugs?

These pests are not insects—they're arthropods. Although they share similar habitats with insects, they are technically in a different biological group. While these creatures are mostly non-dangerous nuisance pests, understanding their habits is key to managing infestations.

🐛 Sowbugs & Pillbugs (Isopods)

• Size: Less than 2 cm (0.79 inches)
  
  

• Appearance: Oval-shaped, gray to dark slate, armadillo-like exoskeleton
  
  

• Habitat: Moist, dark outdoor areas (under rocks, mulch, and debris)
  
  

• Diet: Feed on decaying organic matter
  
  

Key Difference:

• Pillbugs can roll into a ball
  
  

• Sowbugs cannot; they also have two tail-like appendages
  
  

Indoor Survival: Limited — they usually die quickly indoors due to dry conditions.

🦂 Centipedes

• Size: 2.5–5 cm (1–2 inches)
  
  

• Color: Yellowish-gray with dark stripes
  
  

• Legs: 15 pairs (long and fast-moving)
  
  

• Origin: Native to Mexico, now common across North America
  
  

House Centipedes are beneficial predators that eat pests like:

• Spiders
  
  

• Bed bugs
  
  

• Cockroaches
  
  

• Silverfish
  
  

• Ants
  
  

• Carpet beetles
  
  

Bite Risk: Rare, mildly painful (like a bee sting), but not dangerous to humans or pets.

🐍 Millipedes

• Shape: Rounded body with two pairs of legs per segment
  
  

• Movement: Slow-moving, coil up when disturbed
  
  

• Diet: Decomposing organic material
  
  

• Survival Indoors: Poor — they dehydrate quickly in dry home environments
  
  

⚠️ Are These Pests Harmful?

No, they are not harmful.

• They do not bite, sting, or spread disease.
  
  

• They do not damage wood, clothing, or food.
  
  

• They are often found indoors due to high moisture levels.
  
  

Fun Fact: Centipedes help naturally control other pest populations, and millipedes, sowbugs, and pillbugs aid in breaking down organic matter, enriching your garden soil.

🧹 How to Get Rid of Centipedes, Millipedes, Sowbugs & Pillbugs

✅ 1. Physical & Environmental Control (Most Effective Method)

🔧 Outdoor Prevention

• Improve drainage: Ensure the ground slopes away from your home's foundation
  
  

• Clear debris: Remove leaf litter, mulch, compost, stones, and wood piles
  
  

• Use coarse mulch: Allows better airflow and less moisture retention
  
  

• Trim vegetation: Keep shrubs and plants pruned to increase ventilation
  
  

• Seal entry points: Caulk cracks in the foundation, around windows and doors
  
  

• Repair water leaks: Fix any exterior leaks or dripping faucets
  
  

🌬 Indoor Moisture Control

• Use a dehumidifier in basements or crawl spaces
  
  

• Install ventilation fans in bathrooms
  
  

• Avoid overwatering indoor plants
  
  

• Allow soil to dry between waterings
  
  

• Keep firewood outside, or inspect it for pests before bringing it in
  
  

🪤 2. Natural Pest Control Solutions

💨 Diatomaceous Earth (DE)

• What it is: A non-toxic powder made from fossilized marine plankton
  
  

• How it works: Scratches the outer shell of arthropods, causing dehydration and death
  
  

• Where to use: Cracks, crevices, behind appliances, under sinks
  
  

• Important: Must stay dry to remain effective — wear a mask when applying
  
  

Safe for: Humans and pets (when used properly)

🧪 3. Use of Domestic-Approved Pesticides

Note: Indoor pesticide use is generally unnecessary for these pests, as they naturally die indoors from lack of moisture. Focus on outdoor habitat reduction first.

If needed, consider:

• Domestic-class insecticides for perimeter treatments
  
  

• Choose products with a PCP (Pest Control Products) number, approved by Health Canada
  
  

• Always follow label instructions carefully
  
  

🏠 When to Worry About Infestations

A few occasional arthropods indoors are normal, especially in damp areas like:

• Bathrooms
  
  

• Basements
  
  

• Crawl spaces
  
  

• Laundry rooms
  
  

However, a persistent infestation of sowbugs, pillbugs, or millipedes indoors may point to:

• Excess moisture
  
  

• Rotting wood
  
  

• Foundation leaks
  
  

• Inadequate ventilation
  
  

📝 Summary: Quick Pest Control Checklist

Action

Frequency

Remove outdoor debris

Weekly

Fix leaks and seal cracks

As needed

Run dehumidifiers in damp areas

Daily or as needed

Apply diatomaceous earth

Monthly or when pests are spotted

Monitor pest activity

Monthly

🌿 Final Thoughts: Should You Worry?

No, these pests are mostly beneficial and harmless.
But if their numbers increase indoors, it may be a sign of a moisture problem in your home.

By combining moisture control, physical exclusion, and natural remedies like diatomaceous earth, you can effectively keep centipedes, millipedes, sowbugs, and pillbugs out of your home—without the need for harsh chemicals.