The creature commonly known as the rolly polly, pill bug, or woodlouse is often mistaken for an insect, but it is actually a terrestrial crustacean, related to shrimp and crabs. This small, segmented animal is one of the only crustaceans that has adapted to live its entire life cycle on land. While generally harmless outdoors, pill bugs become a nuisance when they migrate indoors, typically seeking moisture or shelter when outdoor conditions become unfavorable. Managing a pill bug presence requires understanding their biological needs and applying practical, non-toxic methods for both immediate removal and long-term prevention.
Why Rolly Pollies Are Present
Pill bugs are heavily dependent on high moisture environments because they breathe using gills, which must remain damp to function. Unlike insects, they lack a waxy cuticle layer, making them highly susceptible to desiccation. This means they naturally congregate in damp, dark areas with limited airflow, such as under rocks, logs, boards, or dense layers of mulch and leaf litter.
These crustaceans are primarily detritivores, performing a beneficial role in the ecosystem by consuming decaying organic matter like dead leaves, rotting wood, and fungi. They constantly search for this combination of dampness and decaying food material. When outdoor conditions become unfavorable, such as during a drought or heavy rain, they may accidentally wander into human structures through ground-level entry points. Once inside a home, they usually die quickly unless they find a severely damp location like a leaky basement or crawl space.
Non-Toxic Removal Strategies
For immediate reduction of a localized population, several non-toxic strategies focus on actively removing or trapping the pill bugs. Hand-picking is one direct approach, best performed at night when the nocturnal pill bugs are most active. Indoors, a vacuum cleaner is an effective tool for quickly removing any pill bugs that have managed to cross the threshold.
Targeted trapping methods take advantage of the pill bug’s attraction to moisture and fermenting organic material. A simple trap uses a shallow container, such as a pie plate, sunk into the ground with its rim flush with the soil surface. Filling this container with beer or a mixture of yeast and water will lure the pill bugs, causing them to fall in and drown.
Certain food items can be used as bait to draw the crustaceans away from vulnerable plants. Placing melon rinds or hollowed-out potato halves, cut-side down, in garden beds will draw them in. These traps should be checked daily, and the collected pill bugs relocated or disposed of away from the garden area. Another easy method is to place a damp piece of rolled-up newspaper or a board on the ground, creating a dark, moist daytime hiding spot for them to gather.
For a localized, non-chemical barrier, food-grade diatomaceous earth (DE) can be applied to areas with pill bug activity. DE is a fine powder made from the fossilized remains of diatoms; its sharp, microscopic edges abrade the pill bug’s exoskeleton, leading to fatal dehydration. Because its effectiveness is negated by moisture, it must be reapplied after rain or heavy watering. Mild insecticidal soap solutions can also be used as a direct spray for spot treatments.
Eliminating Attractive Conditions
The most successful long-term strategy involves modifying the environment to eliminate the moist, dark conditions pill bugs require for survival. Addressing structural water issues is a primary step, including ensuring that gutters and downspouts function correctly to divert rainwater away from the foundation. Grading the soil around the house so it slopes away from the foundation will prevent water accumulation against the structure.
Pill bugs thrive in sheltered locations that retain moisture, so removing these harborages is essential. This means clearing away leaf litter, grass clippings, and debris directly adjacent to the house. Woodpiles and stacks of stored materials should be moved away from the foundation and elevated off the ground to allow for air circulation and drying.
Mulch, while beneficial for plants, creates an ideal environment for pill bugs because it holds moisture and provides a food source. Reducing the depth of mulch, or pulling it back several inches from the foundation and vulnerable seedlings, allows the soil surface to dry out. Sealing potential entry points into the home is necessary to prevent accidental indoor migration. This includes using caulk or an epoxy sealer to close foundation cracks and installing tight-fitting door sweeps and weather stripping on exterior doors.