Booklice are small, almost microscopic insects that are grouped in the insect order Psocoptera. Other members of this order are the “barklice.” Most of the species found in buildings are wingless, and because they often live among books and papers, they are usually called “booklice.” Psocopterans feed on moulds, fungi, cereals, pollen, fragments of dead insects or other similar materials. Booklice (in houses) are frequently found around old books and papers.

Size: 1/16″

Colour: Grey or Brown

Behaviour: Booklice are found in areas with high relative humidity. Hence, common invasion sites are basements, crawlspaces, and areas with dampness, leakages, and mould growth. Mould is the primary food for most of the species. Booklice are very sensitive to humidity in the surrounding environment and cannot survive if it drops low. In such cases, they tend to migrate to areas of high relative humidity. Humidity below 50% is detrimental to their growth.

The majority of the psocopterans live outdoors and occur on the bark or leaves of trees or shrubs. A few species live indoors. Booklice are very common in libraries, paper storage warehouses, packing and shipping warehouses that contain a lot of cardboard boxes, accounting and billing offices, large secretarial offices, and other places in which large quantities of paper are stored or used daily. In houses, these small insects can be found infesting cereals, grits, flour, and grain in the kitchen or basement. They can be very common in the late summer when temperatures and relative humidity are high. The most favourable environment for booklice is one of high temperature and relative humidity.

The best way to manage infestation is to remove any infested food, wipe away any visible mould growth and control the humidity. Good ventilation is key to success. Keep windows and doors open as much as possible to ventilate and dry out the moisture.

Booklice feed on moulds and will overrun cereals and similar materials that support mould growth. Their presence, therefore, is a nuisance and can render some foods unfit. The starchy paste of wallpaper and books can also support mold growth or be attacked directly by booklice. Outside of annoyance, their damage is insignificant.