Pill bugs thrive only in areas of high moisture, and tend to remain hidden under objects during the day. Around buildings they are common under mulch, compost, boards, stones, flowerpots, and other items resting on damp ground. Another frequent hiding place is behind the grass edge adjoining sidewalks and foundations.
Pillbugs may leave their natural habitats at night, and crawl about over sidewalks, patios, and foundations. Common points of entry into buildings include door thresholds, especially at the base of sliding glass doors. They often invade crawl spaces, damp basements and first floors of houses at ground level. Frequent sightings of these pests indoors usually means that there are large numbers breeding on the outside, close to the foundation. Typically however, if pill bugs enter a structure, they will often dry out and die.
There are a few main strategies to removing pill bugs from your home including minimizing moisture, removing debris, and sealing pest entry points to your home. The most effective, long-term measure for reducing indoor entry of pill bugs is to minimize moisture and hiding places near the foundation. Keep your homes and the areas around your home clean and dry. Don't allow water to accumulate near the foundation or in the crawl space. Divert water away from the foundation wall with properly functioning gutters, down spouts and splash blocks. Repair leaking faucets, water pipes and air conditioning units. Control humidity in crawl spaces and basements by providing adequate ventilation, sump pumps, and dehumidifiers as needed. Since pillbugs require moisture, they do not survive indoors for more than a few days unless there are very moist or damp conditions.
Pill bugs can also be avoided by eliminating food sources such as vegetable or plant debris. Remove leaves, grass clippings, heavy accumulations of mulch, boards, stones, boxes, and similar items laying on the ground near the foundation. Items that cannot be removed should be elevated off the ground. Remove heavy accumulations of mulch and leaf litter.
To prevent pill bugs from entering your home, seal cracks and openings in the outside foundation wall, and around the bottoms of doors and basement windows. Install tight-fitting door sweeps or thresholds at the base of all exterior entry doors, and apply caulk along the bottom outside edge and sides of door thresholds.
Insecticides are of little use in controlling these pests. Once inside, pill bugs soon die from a lack of moisture. Removal with a broom or vacuum is all that is needed. For large infestations, insecticides may help reduce inward migration of these and other pests when applied at common outdoor entry points, along the bottom of exterior doors, around crawl space entrances.