Pest Library
Pillbug and Sowbug
Pillbugs and sowbugs are small gray armored crustaceans — not insects — that live under mulch, flowerpots, boards and stones. Pillbugs roll into a tight ball when disturbed; sowbugs cannot. Both depend on constant moisture, so indoor sightings point to damp conditions right against the structure.
Profile
- Scientific name
- Armadillidium vulgare and Oniscus spp.
- Identification
- Segmented gray armored body with seven pairs of legs. Sowbugs have two small tail appendages; pillbugs do not.
- Typical size
- About 1/4 to 1/2 inch.
- Behavior
- Nocturnal, feeds on decaying plant material, and dies quickly in dry indoor air.
- Habitat
- Mulch, compost, under pots and boards, crawl spaces and damp garage corners.
- Diet
- Decaying plant material and mold.
- Lifecycle
- Females carry young in a brood pouch; development takes several months.
- Why it matters
- Harmless to people and structures. Heavy populations can graze seedlings in a garden.
- DIY considerations
- Moisture and landscape adjustments resolve most complaints without treatment.
- Professional considerations
- Perimeter service reduces entry during wet periods, with moisture and landscape recommendations documented.
Signs of activity
- Gray armored bugs under flowerpots, boards and mulch
- Sightings in garages and bathrooms after heavy rain
- Dead specimens along thresholds and baseboards
Prevention
- Reduce mulch depth against the foundation and remove ground-contact debris
- Raise flowerpots and stored items off the soil
- Correct drainage and crawl space moisture
- Maintain door sweeps and seal threshold gaps
Sources
Related information
Seeing pillbug and sowbug at your property?
Book online or request service through our secure customer portal. Tell us what you are seeing and where the property is located.