Sowbugs, pillbugs, millipedes and centipedes
Sowbugs and pillbugs are closely related to shrimp, crabs and lobsters. Although they may occasionally invade the home, they normally prefer moist areas outdoors at the soil surface in mulched flowerbeds, leaf litter, grass clippings and other debris around foundations. However, cracks between slabs and porches and in basement walls provide excellent hiding places from which these occasional invaders can enter homes. These pests do not pose an economic or health threat to humans, but some sowbugs occasionally damage roots or the tender stems of plants. Millipedes and centipedes rarely damage seedlings. Sowbugs, pillbugs and millipedes do not harm humans or other animals, and centipedes usually are too small to injure humans. However, large centipedes (4 to 5 inches long) can inflict a wound similar to a bee sting. Annoyance from the presence of these invaders inside the home is the main concern with this group of pests.
Archive version. For most recent information see extension.missouri.edu.