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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Psocids Love a Damp Location

This article was published originally on 10/14/2009

Psocids are one of the small, occasional pests you might encounter around the house (silent "P" -- pronounced "sew-sid").  Psocids are up to 3/16 inch in length and appear translucent to off-white in color.   Psocids found indoors are usually wingless like the ones in the photo below.  Psocids on tree trunks outdoors may be wingless or winged.
Psocids are also known as booklice (if indoors) and barklice (when outdoors) even though the name is potentially misleading by suggesting these might be blood-sucking pests.  Psocids are scavengers that feed on decaying organic matter, molds and mildew and are frequently abundant in damp locations. They take advantage of moist areas and are a symptom of a problem (moisture or out-of condition foods, grains, etc.). Psocids are annoying by their presence but are not harmful - they cannot bite or sting and they do not destroy products that are not already compromised.
Insecticides are not needed for psocids. Locate and eliminate infested items and correct moisture problems.
Please refer to our online article for more details.
Psocids photographed inside a plastic bag.Psocids photographed inside a plastic bag.
Psocid, close up.  Note narow thorax and threadlike antennae.Psocid, close up. Note narrow thorax and threadlike antennae.