Common Name: Sowbug
Latin Name: Porcellio laevis
Common Family Name: Isopods – Porcellionidae
Latin Family Name: Porcellionidae
Other Names: Wood lice (in England)
Origin: It is believed this animal is native to Europe, but it now is found throughout the world.
Biology: Pillbugs and sowbugs are most closely related to other Crustaceans, such as crabs and crayfish, and similar to their relatives they require areas of high moisture for survival. Breathing is done through primitive forms of gills, and they are unable to effectively control the loss of moisture through these openings, thus restricting them to very damp environments. Food is usually decaying organic and vegetable materials, although they also may attack living plant tissues and turf, as well as fruits and vegetables. Sowbugs and pillbugs can live up to 2 years, and they continue to molt throughout their lifetime. Females produce a batch of around 25 eggs that hatch within a pouch on her ventral side, referred to as a marsupium. The nymphs may be carried in this pouch for an average of about 45 days, at which time they are able to open the pouch and leave of their own accord. After molting again the female regains the use of the pouch and she may have several broods each year.
Identification: Sowbugs are up to a half inch long, dark gray in color, and composed of around 10 lateral plates that overlap each other. They are not capable of curling up into a tight, round ball when disturbed, different from the related pillbugs. They also may be distinguished from pillbugs by the presence of a pair of cerci at the posterior end that are visible from above, whereas in pillbugs these cerci cannot be seen. There are 7 pairs of legs.
Characteristics Important in Control: Control of sowbugs and pillbugs relies heavily on changes in their environment. Since they rely on excessive moisture for survival the elimination of unnecessary moisture in the outdoor environment will reduce the populations. These are nocturnal animals, and removal of any materials that rest on the soil also eliminates harborage sites, including lumber and yard debris. Thick vegetation and thick covers of mulch will provide excellent harborage sites, and these need to be considered as well. To reduce the ability for pillbugs and sowbugs to enter structures, along with the physical controls mentioned, a barrier treatment with a residual insecticide will eliminate many of them as they crawl against the foundation and building perimeter.