Family: Liposcelididae, Trogiidae
Booklice are small insects that do not bite or sting and can be a pest indoors. These insects are usually wingless, measure about 1-2 mm (<1/10 inch) in length, and often appear as moving white or yellow specks. Upon magnification, booklice resemble miniature termites but have a pronounced head with well-developed eyes, long filamentous antennae, and a constricted neck region. Nymphs resemble adults but are smaller. Although infestations of booklice are often comprised of more than one species, Lepinotus reticulatus is most associated with indoor infestations in Colorado. Generally, species in the genus Liposcelis can be serious pests of stored products.
- Booklice are small insects that feed on molds that grow on dried plant matter. These insects do not bite or sting and are most active in warm, moist weather. They often appear as small specks moving about on the surfaces of infested areas.
- Monitoring can be accomplished by closely inspecting damp areas and stored foods or deploying glue traps.
- Preventative measures include maintaining humidity below 50% and placing stored food in tightly sealed containers.
Adult booklice. Note the well-developed eyes, long filamentous antennae, and constricted thorax just behind the pronounced head. Image credit: Mohammed El Damir, Bugwood.org
Nymph booklice. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org
Life history and habits
Females lay eggs singly or in small clusters and can produce up to 60 eggs during the summer. The eggs are often covered with a protective silken web or debris. The nymphs develop through four or six instars until maturing into adults. An individual can complete its development in 30 days under favorable environmental conditions, and multiple generations can be produced each year indoors. Booklice are most active under warm, moist conditions, and are commonly noticed in damp rooms, storerooms, or libraries.
These insects have chewing mouthparts for feeding on microscopic molds that grow on plant- or animal-based material, including paper based-items such as books or wallpaper. Booklice can damage books since they also feed on starch-filled pastes in book bindings, and large infestations can contaminate food products.
Food can be stored in tightly sealed containers to prevent infestations of booklice. When possible, under 50% humidity should be maintained to slow the growth of mold and kill booklice. Infested food should be discarded immediately, and vacuuming or wiping down food storage areas is also recommended. Furniture, bedding, and other movable furnishings can be thoroughly laundered and cleaned. When possible, articles resistant to freezing or heat can be placed in plastic bags and placed in a freezer at -18°C (0°F) for four days or heated to 82 °C (180 °F)
Insecticides are available for booklice, but chemical control is not usually necessary. Contact insecticides in aerosol formulations can be applied to cracks and crevices, and fumigants can help control booklice in small storage areas or other confined spaces.
CSU (n.d.). Booklice. Colorado State University – Colorado Insects of Interest. Available https://webdoc.agsci.colostate.edu/bspm/Hexapoda%20(Insects)/Booklice.pdf
Drees, B., (n.d.). Booklice. Texas AgriLife Extension Service. Available https://extensionentomology.tamu.edu/publications/booklice/
Oi, F., P. Koehler, D. Branscome, and B. Bayer. (n.d.). Booklice and Silverfish. University of Florida – Extension. Available https://edis.ifas.ufl.edu/publication/ig094
Opit, G., J. Throne, and K. Friesen. (n.d.). Stored-Product Psocid Identification Website. Available https://www.ars.usda.gov/plains-area/mhk/cgahr/spieru/docs/psocid-id-introduction/