Sowbugs and Pillbugs and Rolly Pollies
By : Tim Gibb, Integrated Pest Management Extension Specialist

I don't know if it is a scientifically correct name, but as kids we called them "rolly pollies". They were the small, gray, convex bugs that roll themselves up into perfectly tight little balls when agitated. Rolling them from hand to hand provided hours of entertainment. Better yet, we found that laying on our stomachs and closing one eye we could shoot them across a smooth surface with amazing accuracy. Miniature bug bowling. Unfortunately, I have found that doing the same thing as an adult only elicits weird stares from anyone passing by and the occasional murmurs about "it takes all kinds" or something similar.

Rolly pollies are even more interesting now that I have learned about their behavior and biology. Both pillbugs (that roll themselves into balls) and their closely related cousins the sowbugs actually are not insects at all - but are crustaceans, related to crabs, shrimps and lobsters. These are the only crustaceans that have adapted to spending their entire life out of water. Even though officially terrestrial, pillbugs and sowbugs are restricted to damp environments and still breath by means of gills. They have 7 pairs of legs and a life cycle that may last up to two years.

In general, rolly pollies are beneficial decomposers in the garden, breaking down dead plants and organic materials and facilitating decomposition.
Because of where they live, however, they can sometimes cause problems by eating ripe fruit or vegetables that lay in direct contact with the soil. In cooler periods when plant growth is slow, pillbugs and sowbugs may damage the succulent stems or root systems of select garden plants. In addition, rolly pollies can sometimes enter and become a nuisance pest inside homes, especially if vegetation is grown right up to the sides of the house.

The most effective strategies for controlling rolly pollies include modifications of their preferred habitats. By creating less damp environments, thinning plants, removing piles of wood or organic debris including decomposing leaves, clippings and sometimes mulch, away from susceptible plants or the home often helps. If chemical controls are required, place them directly into those damp areas, under mulch or under the leaves of heavily shaded areas of the garden. Better yet, lay down on your stomach, take careful aim and shoot them across the driveway into your neighbors' yard. And don't feel bad doing it. How do you think you got them in the first place?

More Information

Entomology Extension Publication - Millipedes, Sowbugs, and Pillbugs (PDF)

Quick Facts

Pillbugs and Sowbugs may damage the succulent stems or root systems of select garden plants.