Sowbugs & Pillbugs
Extremely common in Maine basements and crawl spaces, these moisture-loving crustaceans indicate damp conditions.
About Sowbugs & Pillbugs in Central Maine
Sowbugs and pillbugs (roly-polies) are not actually insects — they're terrestrial crustaceans, more closely related to shrimp and lobsters than to ants or spiders. They breathe through gill-like structures and require constant moisture to survive. In Central Maine, they're extremely common in basements, crawl spaces, garages, and around foundations where dampness accumulates. Pillbugs roll into a tight ball when disturbed, while sowbugs cannot. Both feed primarily on decaying organic matter, and while they don't bite, sting, or spread disease, their presence in large numbers is a reliable indicator of excessive moisture problems that could lead to more serious issues like mold, wood rot, or attracting other pests. Addressing the moisture issue is the key to lasting control.
Sowbugs in Maine cellars and what they say about moisture
Sowbugs and pillbugs are isopods, and University of Kentucky entomologists describe them as rarely more than 3/4 inch long, living about three years, and producing one or two broods a year of roughly two dozen young. A newly hatched isopod takes two to three months to mature. They are mostly active at night and depend heavily on humidity, which is why they gather where it is dark and damp.
That describes a lot of Central Maine cellars. Stone foundations, dirt-floor crawl spaces, bulkheads and basement window wells hold moisture and organic debris, and sowbugs wander in from mulch and leaf litter piled against the foundation. Indoors they seldom last long: Kentucky notes it is almost impossible for them to survive without high moisture. A steady stream of live ones in a finished room means they are coming in from a damp spot close by, or the room itself is damp.
Because indoor insecticide applications do not work on them, control comes from removing moisture and hiding places. Rake leaves, mulch, rotting wood, stones and flowerpots away from doors and the foundation, make sure water drains away from the house, and seal gaps at doors and windows. Where numbers stay high, Kentucky's guidance is a pyrethroid treatment around the foundation perimeter in spring or fall, applied after leaf litter is cleared. They also chew tender seedlings, so plants started in a damp cellar can be damaged.
Campbell's Pest Control offers general pest control in Augusta, Waterville, Bangor and the other Central Maine towns we serve.
Signs of Sowbugs & Pillbugs
- Finding roly-polies or flat, oval grey bugs in basements, bathrooms, or garages
- Congregations under potted plants, mulch, or landscaping stones near the foundation
- Large numbers appearing in crawl spaces or utility rooms
- Activity increases after rain or in humid conditions
- Presence of other moisture-loving pests (millipedes, earwigs, springtails)
Prevention Tips
- Reduce moisture in basements and crawl spaces with dehumidifiers
- Ensure proper drainage away from the foundation — clean gutters and extend downspouts
- Pull mulch, leaf litter, and ground cover at least 12 inches from the foundation
- Seal cracks in foundation walls, basement windows, and door thresholds
- Improve ventilation in crawl spaces and damp areas
- Remove debris piles, rotting wood, and standing water near the home
- Move flowerpots, stones, boards and firewood away from doors and the foundation
- Clear leaf litter out of window wells and around the bulkhead each fall
- Run a dehumidifier in stone or dirt-floor cellars through the humid months
- Weatherstrip bulkhead and basement doors
- Skip indoor insecticide and fix the moisture instead
Did You Know?
- 1.Pillbugs and sowbugs are crustaceans — they're more closely related to lobsters than to insects
- 2.Pillbugs carry their eggs in a fluid-filled pouch on their underside, similar to a kangaroo
- 3.They play an important role in decomposition, breaking down dead plant material and recycling nutrients into the soil
Need Help With Sowbugs & Pillbugs?
Our general pest control service targets sowbugs & pillbugs at the source. Contact us for a free inspection and quote.
