Sowbugs: Another Wet Weather Annoyance

Wet conditions outdoors are producing a bumper crop of many pests; everything from mosquitoes and slugs to millipedes and sowbugs. See the "resources" section at the end of this newsletter for directions to past articles on these and other pests.

Sowbugs are crustaceans more closely related to shrimp and crayfish than to insects. Other names used for these very common animals include pillbugs, roly-polies and isopods. Sowbugs are 1/4 to 1/2 inch long, dark to slate gray and possess seven pairs of legs. The oval, segmented body is convex above but flat or hollow underneath.

Sowbugs live in damp habitats where they feed on decaying vegetable matter. Outdoors, these scavengers are found under dead leaves, rocks, boards, grass clippings, flower-bed mulch and other objects on damp ground. Like other accidental invaders, they wander indoors by mistake. Sowbugs do not bite or sting and cannot damage household furnishings. They are a nuisance only. Sowbugs must have moisture to survive and die quickly if there is not a damp location where they can hide.

Occasional annoyance by sowbugs should be tolerated; invaders can be vacuumed, swept or picked up and discarded. Persistent problems will require locating the sources of the sowbugs and eliminating or treating these areas. Sealing foundation, door and window cracks and gaps where the sowbugs enter may be sufficient for control. Indoors, moist hiding places should be removed or modified by correcting water problems, improving ventilation or other humidity control measures.

Residual insecticide treatment may be used outdoors or indoors. Common lawn and garden insecticides such as Sevin, diazinon, malathion, and Dursban can be applied around the house to breeding sites or as a barrier. The treatment must be applied with enough water to get the insecticide down to the soil surface. Light application of "ant and roach killer" or "home pest control" indoor insecticides (as for cockroaches) to cracks and corners of infested areas may be of some benefit.

This article originally appeared in the July 10, 1998 issue, p. 93.


Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on July 10, 1998. The information contained within may not be the most current and accurate depending on when it is accessed.