Facts, Identification & Control
Despite their name, sowbugs, sometimes called a woodlouse, are not really bugs. They are land-living crustaceans. There are two common species in the U.S., Porcellio laevis and P. scaber.
Sowbugs are flat, oval creatures. They are about 1 cm long. Their body has several segments. They have seven pair of legs and two pair of antennae. Another crustacean, the pillbug, resembles the sowbug. Sowbugs cannot roll up when they are disturbed like pillbugs do. Sowbugs have two appendages that look like tails. Pillbugs do not have the appendages.
Behavior, Diet & Habits
Sowbugs are not able to retain water in their bodies, so they spend most of their time in damp places. Outdoors they hide under logs, rocks, flowerpots and trash cans. Sowbugs eat organic debris and decaying plants, so it is common to find them under mulch in flowerbeds. To conserve moisture, they are usually active at night.
Sowbugs usually come into homes through ground-level doors and windows. Sliding glass doors seem to be a favorite entrance for them. Homeowners often find sowbugs in basements and other places that have a damp, humid environment. Sowbugs wander to all parts of the home. They also invade garages and storage buildings. Since many areas in a home are too dry for sowbugs, they usually die after they come indoors.
The best way to prevent sowbugs is eliminating their hiding places. If there are no damp harborages, the sowbugs will leave or die. There are several things that homeowners can do:
Stack firewood off of the ground and move it away from the house. Move logs, boards and stones that sowbugs could use as hiding places. Move piles of dead leaves and grass clippings. Check downspouts to be sure they drain away from the foundation.
Pull mulch in flowerbeds away from the foundation. Create a zone next to the home that is free of mulch and leaves. The zone should be 15 to 30 cm wide. This will discourage sowbugs and other pests from nesting. It may be necessary to trim limbs of trees or shrubs if they cause a damp shady environment near the foundation.
Make sure exterior doors close tightly. Replace weather stripping and door sweeps that are missing or damaged. Make sure there is a door on the crawl space entrance to keep sowbugs out. Check crawlspace vents to be sure they are open to allow ventilation. Sometimes people who live in brick homes insert small squares of plastic screening into weep holes to block sowbugs from entering the home.
Waterproofing might help eliminate dampness on basement walls. Check with the specialists at the home store to see what products they recommend. Sometimes a dehumidifier will help reduce the dampness in a basement.