WSU Extension


Sowbugs and pillbugs

(revision date: 7/14/2015)

Use Integrated Pest Management (IPM) for successful pest management.

Sowbugs and pillbugs are not insects. They are crustaceans and as such are more closely related to crabs, shrimp, etc. Sowbugs and pillbugs are often considered pests by gardeners because they are sometimes associated with gardens. They may be found under boards in gardens and in a variety of damp places. In many cases, they are found in rotting damp wood such as stumps or in cedar shakes where there is a moisture problem. They are generally considered as beneficial creatures due to their role in recycling nutrients. Sowbugs are grayish in color and prefer damp habitats. Pillbugs are bluish-black. Unlike sowbugs, they can roll up into a ball like an armadillo when disturbed. They appear to tolerate drier conditions than sowbugs. Both can measure from 1/4 to 3/8 inch in length when fully-grown. Sowbugs are the major food prey of certain spiders.
Management Options

Non-Chemical Management
  • Because sowbugs and pillbugs are occasional to frequent visitors in our homes, we must make special efforts to make it difficult for them to gain access. For example, decreasing or eliminating space under door thresholds, securing windows (particularly basement windows) and screens and performing any other methods to “bug-proof” the home will go a long way in discouraging their entry.
  • Physical destruction, vacuuming or careful removal and placing them outdoors where they can be useful are possibilities.
Select non-chemical management options as your first choice!

Chemical Management

None recommended.

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Caption: Sowbug
Photo by: Art Antonelli