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Color of booklice

Light tan, brown, or creamy yellow with brown bands. Colors may vary with species.


One of the only insects with a 'neck' – which is actually the prothorax. They have soft bodies, a round head with chewing mouthparts, and long, threadlike antennae. Not all have wings, but if so, they are veined and cellophane-like, and held up like their own personal roof when resting. The front wings are larger than hind wings. The young resemble adults but are wingless. They are active crawlers, and often associated with damp books, hence their name.


Where found

There are 287 species throughout the world and in the U.S. They like damp, secluded places in grass, dead leaves, and litter under trees, shrubs and damp wood. Also under lichens, moss, or bark, where they gobble up molds and mildews. They are common along coping joints around swimming pools.


Often caught with a good book – or rather, chowing down on the mildew, starch sizing, and glue in moldy pages. Also found in sweating pipes, new plaster and sheet rock, damp spills and wooden pallets. Outdoors, they reside under loose, damp bark, and some may be found in grain and agricultural products. You might also spot some in museums or libraries, which are a paradise of neglected books.


They have two main food groups: mold, and mildew.


Eggs are laid bare or encrusted with or without webbing. They breed in wall voids, storage trunks, groceries, stored flour, rugs, paper, cartons, rope fibers, closets, cabinets and even pianos. In some species it only takes one to reproduce – meaning males are not needed. They mature in 4-6 nymphal instars (stages). They need plenty of moisture, with a minimum relative humidity of 50-60%, as they lose body moisture through their exoskeletons. They also rely on high humidity for their food source, mold, to grow. When humidity levels drop too low they may migrate elsewhere. In warm weather they can mature in 3-4 weeks. Typically, outdoor species have wings, while indoor species have small wings or none at all.


Booklice are as bad for books as Fahrenheit 451. They wreak havoc in libraries and museum collections, as well as stored products and food processing plants. They are a nuisance in homes and sometimes commercial buildings. The presence of booklice bodies in house dust are believed to contribute to asthma attacks.


Dampness and mold growth supports breeding, continuing the reign of established populations. They may also invade via stored goods, groceries, cartons, paper and construction material.

Good riddance

Psocids rely on high amounts of moisture to survive, so drying out areas of concern may, in some cases, control this insect without the use of pesticides. Pesticides are necessary when they are present in large numbers. You will need to prepare food areas, and keep humidity below 50%, as they have trouble surviving dry conditions. When using any pesticide, be sure it is registered for the target pest/location. Read the entire label prior to use. Follow all label directions, restrictions and precautions.

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