Ornamental & Turf Insect Note Logo


James R. Baker, Extension Entomologist Emeritus

CAUTION: This information was developed for North Carolina and may not apply to other areas.

General Information

Oniscus asellus, Porcellio scaber, Armadillium vulgare, Armadillidiae, ISOPODA

pillbug drawingSowbugs and pillbugs are about 1/2 inch long, dark gray and oval. Sowbugs are flattened and have two tail-like structures on the rear end of the body that pillbugs do not have. Sowbugs and pillbugs are small animals more closely related to lobsters than to insects. Although sowbugs resemble pillbugs (roly-polies), sowbugs are incapable of rolling up into a ball.


pillbugA female sowbug or pillbug carries her eggs in a pouch for several weeks until they hatch. The young remain in the pouch for a time. About 50 young develop in each brood.

Sowbugs and pillbugs feed on decaying vegetation and sometimes tender vegetation. They breathe by means of gills and live under vegetable debris and other objects lying on damp ground. They are sometimes found in damp basements and crawl spaces, but they do no structural damage. They die soon after and may be swept up. Large numbers of sowbugs or pillbugs in a basement or crawling in the upper part of a house usually mean an abundant number outside.

rolled up pillbug Although primarily scavengers, during wet weather, sowbugs and pillbugs may come indoors and seek refuge under and in potted plants. Occasionally, sowbugs and pillbugs feed on the roots and tender portions of vegetable and ornamental plant seedlings. Feeding would tend to be at night or in the dark. They may infest house plants where they might damage roots if severe.



Rake all debris away from the foundation of buildings occasionally. Plug the foundation and around window frames with caulking compound or other material. Keep basements dry by cross ventilation during the summer. Keep the area free of rotting wood, decaying vegetable matter, soil and other materials that provide food and hiding places for sowbugs and pillbugs. Keep windows tightly screened during the ventilation period.

Treatments should be made to and near foundation walls, around and beneath door steps and porches, subfloor crawl spaces, damp basements and similar areas immediately adjacent to the building. The outdoor application of chemicals should extend to at least 10 feet around the structure being protected. Any of the outdoor lawn and garden products labeled for these arthropods or one of the following chemicals may be used.

Pesticide  (Trade Name)  Formulation 
acephate  (Orthene)  75% soluble powder 
cyfluthrin (Decathlon) 20% wettable powder
cyfluthrin (Tempo 2) 24.3% emulsifiable concentrate
bifenthrin (Talstar) 10% wettable powder 
carbaryl (Sevin) various

Many "All Purpose" insecticides off the shelf are effective and suitable for home use. Check the label!

Interesting Sources of Information
Porcellio Scaber Behavior
Young Naturalist Awards 2002
Animal Diversity Web
Other Resources

For assistance with a specific problem, contact your local North Carolina Cooperative Extension Service personnel.

Published by North Carolina Cooperative Extension Service

Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
© 2001 NC Cooperative Extension Service
Prepared by: James R. Baker & S. B. Bambara, Extension Entomologists

July 1994 (Revised) May 1997

Web page last reviewed January, 2011 by the webperson.