Rollie pollies (or pill bugs) are small, segmented creatures that become an unwelcome nuisance when they appear indoors. They are harmless to humans and do not bite, sting, or carry disease. However, their presence in large numbers often signals a deeper issue with the home’s environment. These creatures enter structures accidentally while searching for moisture or escaping unfavorable outdoor conditions. Understanding their biology and the environmental factors drawing them near is the first step toward effective and long-term management.
What Exactly Are Rollie Pollies?
Rollie pollies are often mistaken for insects, but they are actually terrestrial crustaceans, related more closely to shrimp and lobsters than to typical garden pests. They belong to the order Isopoda. Their bodies are characterized by seven pairs of legs and a segmented, armored appearance made up of overlapping plates. This structure allows them to curl into a tight ball when disturbed, a defense mechanism known as conglobation.
These organisms cannot retain water efficiently and rely heavily on high humidity and moist environments to breathe through their gill-like structures. They are primarily decomposers, feeding on dead and decaying plant matter, which benefits soil enrichment and nutrient recycling. This dependence on moisture means that when their outdoor habitat becomes too dry or too wet, they migrate, often leading them directly toward building foundations.
Pinpointing Why They Are Present
Rollie pollies are drawn to environments that mimic their natural, damp habitat, meaning areas with excessive moisture and abundant organic material. Their accidental entry into a home signals that conditions immediately surrounding the structure are favorable. Common attractants include poorly draining soil, leaky outdoor faucets, or air conditioning units that drip condensation near the foundation.
Accumulations of decaying matter act as both a food source and a protective hiding spot, especially during the day. This includes thick mulch, leaf piles, grass clippings, or rotting wood left near the house perimeter. When these conditions exist, large populations develop, and the creatures migrate indoors through small structural gaps. Indoor sightings, particularly in basements or ground-floor bathrooms, indicate a localized moisture problem within the home, such as a plumbing leak or high humidity.
Modifying the Environment for Long-Term Prevention
The most effective, long-term solution involves eliminating the moist conditions that allow rollie pollies to thrive near the foundation. This begins with correcting drainage issues, ensuring that gutters and downspouts are clean and directing rainwater several feet away from the house. The soil surrounding the foundation should also be graded to slope downward, guiding water away from the structure.
A significant step is removing organic debris that provides shelter and food. This means clearing away leaf litter, grass clippings, and old planters that sit directly on the ground. If using mulch near the foundation, consider replacing thick layers with gravel or pine needles to reduce moisture retention. Alternatively, maintain a dry, bare strip of ground between the mulch and the house wall. Inside the home, control humidity with a dehumidifier in damp areas like basements or crawl spaces to make the environment uninhabitable.
Finally, physically sealing entry points prevents accidental migration indoors. Inspect the foundation for hairline cracks and use caulk to close them, sealing gaps around utility lines, pipes, and ground-level windows. Install tight-fitting weatherstripping or door sweeps on all exterior doors, especially sliding glass doors, to eliminate common entry pathways.
Targeted Removal and Direct Control Methods
For immediate reduction of existing populations, direct control methods can be employed after environmental modifications are addressed. Physical removal is straightforward; rollie pollies found indoors can be swept up or collected with a vacuum cleaner and disposed of outside. Since they are nocturnal, simple trapping techniques are effective for localizing outdoor efforts.
One common method involves placing a damp, rolled-up newspaper or the hollowed-out halves of a potato or melon rind near areas of high activity. The rollie pollies are attracted to the moisture and shelter, allowing them to be collected and removed the following morning. For persistent outdoor issues, products like food-grade diatomaceous earth (DE) provide a non-chemical barrier. DE is a fine powder that desiccates the bugs by abrading their waxy outer layer, causing them to dry out and die.
Chemical control should be considered a last resort, used only for perimeter defense against heavy outdoor infestations. Granular or liquid insecticides labeled for perimeter use can be applied to a band of soil and foundation extending about three feet out and three feet up from the home. Because rollie pollies are crustaceans and not insects, select a product specifically effective against them. Apply it strictly according to the label instructions, focusing only on the exterior perimeter to prevent further indoor migration.