University of Maryland Extension

Pillbugs and Sowbugs


Pillbugs and sowbugs are oval in shape, convex above and flat beneath. They are gray in color, and 1/2 to 3/4 of an inch long. Sowbugs have two small tail-like appendages at the rear, and pillbugs do not. Pillbugs can roll up into a ball, but sowbugs cannot. Pillbugs and sowbugs live outdoors and like moist locations, such as under objects and vegetable debris. They are beneficial decomposers by feeding on decaying organic matter in the garden.


They may invade damp basements and the first floors of houses. They can be controlled by modifying conditions that are favorable to their development immediately outside the home. Hiding places such as stones or boards close to the house should be removed. Food sources such as leaves, grass clippings or mulch that are close to the house should also be removed. Properly ventilate basements and crawlspaces to eliminate excess moisture. Repair and seal cracks and openings along foundation walls, doors, and windows. Tighten up door and window openings with weather stripping. Insecticide sprays inside homes are not recommended because pillbugs and sowbugs dry out quickly and die making treatment unnecessary. 

sow bug

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