August 1996
SIZE: Small, almost microscopic
COLOR: Transparent to grayish
DESCRIPTION: Booklice are small, almost microscopic insects that are grouped together 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 molds, fungi, cereals, pollen, fragments of dead insects or other similar materials. Booklice (in houses) are frequently found around old books and papers.
HABITAT: 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 on a daily basis. 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 favorable environment for booklice is one of high temperature and relative humidity.
LIFE CYCLE: The eggs are laid singly or in clusters and are often covered with a silken web. Most species pass through six nymphal stages. Time between egg and adult can range from 30 to 60 days, depending on the environment.
TYPE OF DAMAGE: They rarely cause any damage beyond being a nuisance to homeowners.
CONTROL: These insects are probably found in every house in eastern and southeastern U. S. They are usually present in small numbers and go unnoticed. However, when conditions are favorable, and there is adequate food available, booklice can become numerous and a nuisance. Adjusting the environment is the first step in controlling booklice. If there are unnecessary collections of books or papers, remove them, especially if they are in the basement or other damp storage area. Reduce the relative humidity by heating the environment for several days (over a weekend if a commercial establishment). If these methods fail to give adequate control, the use of aerosol insecticides in areas where booklice have occurred will be effective. Whole-house spraying is not necessary.
INTERESTING FACTS: Although there are many species of psocoptera, most people see only a few species that occur in houses or buildings. The term "lice" in the names "booklice" and "barklice" is somewhat misleading for none of these insects are parasitic and they are not louselike in appearance. There are a few instances in which these small insects were the cause of delusory parasitosis, that is, people thought these tiny insects were causing bites and skin rashes. In fact, booklice do not bite humans.