Plant & Pest Diagnostics

Book Lice or Psocids (Order Pscoptera)

Psocids or booklice are found throughout the world in damp and secluded places where they feed on molds and mildews. Psocids are not true lice, although they do resemble immature human lice, they are not parasitic. They are harmless except for contamination of foods and they are nuisances merely by their presence in the homes, food storage and processing building, and other structures. Psocids can be found throughout structure but are normally confined to damp areas such as basements which foster a growth of mold and mildew. They can be very numerous if books and papers, which are very susceptible to mold growth, are stored in these areas. Psocids can be serious pests of stored foods under excessively damp conditions as well. Psocids are very susceptible to changes in relative humidity: if the home or building can be maintained at RH of 50%, psocids will die out in 2 to 3 weeks. With the advent of the heating season, I do not expect the problem to continue much longer and no pesticide application may be necessary. Home-infesting psocids can complete their life cylce in about a month at 80 degrees. Any household insecticide containing pyrethrins (like Raid) with provide temporary control.

Be sure to read and follow all instructions and safety precautions found on the label before using any pesticide.