Attribution: USGS Native Bee Inventory and Monitoring Laboratory [CC-BY-2.0], via Wikimedia Commons
Up to ½ inch long
Sowbugs and pillbugs, often called isopods, are the only crustaceans completely adapted to terrestrial habitats. Sowbugs have oval bodies that are flattened, and have two small appendages extending from the rear. Unlike pillbugs, sowbugs cannot roll into a ball. They have seven pairs of legs. Sowbugs are usually nocturnal and occasionally even bury themselves several inches within the soil. Where large numbers occur outside a foundation, numerous sowbugs may find their way inside where they quickly die from dehydration. They can, however, survive nicely in damp basements, cellars and crawl spaces. They have been found living within homes where a constant moisture source is available due to a water leak. Sowbugs feed on decaying vegetable matter. Many sowbugs live up to two years.
Sowbugs prefer moist environments and are found under objects lying on the damp ground and within leaf litter, mulch, and other types of vegetative debris. In rare cases, they have become pests of young plants.
Sowbug indoor invasions occur when outside conditions support large numbers of these crustaceans. Treatments can provide short-term relief, but correction of such conditions is key to long-term success. Thick ground covers such as ivy, “monkey” grass, etc. should not be located next to or near a foundation as it provides harborage for innumerable insects, spiders, mice and other pests. Items in contact with the soil should be removed, wherever possible. Firewood, lumber and other such stored items should be stacked off the ground on supports away from the building. Exterior cracks and holes should be sealed, especially along the foundation. Weep holes can be “closed” by stuffing pieces of wire mesh or screening into the openings. Inside treatments usually are not needed because sowbugs dry out quickly and die.