• Book louse Miscellaneous

    Book louse
  • Book louse
  • Book louse


It is very difficult to completely eliminate book lice because they are found almost everywhere. It is important to remember that book lice may be tiresome but are not harmful as such. They should also not be confused with head lice as they do not attack the human body.

Without eliminating them completely, you can quickly minimize the problem using an insecticidal powder such as Maheu&Maheu Insecticide Dust or a liquid residual insecticide such as Maheu&Maheu Crawling Insect Killer .


  • Reduce indoor humidity levels (<50%)
  • Eliminate any trace of fungal growth
  • Spot treat with insecticide indoors


  • Get rid of any rotting organic matter around the building including wood chips used in landscaping
  • Seal the outsides of windows, doors, eaves, chimneys, etc. as completely as possible

Description and development

Book lice belong to the family Liposcelidae in the suborder Troctomorpha , order Psocoptera . The most common species in our region is Liposcelis divinatorius Müller . It varies in size from 1 to 2 mm, is pale gray to yellowish-white (beige or very light brown). Its eggs are white, oval-shaped, and covered with a crust. The book louse is a hemimetabolous insect, in other words it undergoes incomplete metamorphosis.
Book lice reproduce through parthoenogenesis. That means that females do not need to be fertilized by males to lay viable eggs. From October to January, at 10 o C to 30 o C, the eggs incubate for about 21 days and the life cycle takes 110 days. However from June to August, when temperatures vary from 15 o C to 32 o C, the eggs hatch after about 7 days and the life cycle lasts only 24 days. Females each lay about 57 eggs during this period. It is clear therefore that temperature and relative humidity have a big influence on the length of the life cycle.

Once the eggs hatch, the white, immobile nymphs are hard to find. They go through three to four molts (usually four), during which the pigmentation process intensifies and they become gray or yellowish white. There can be six to eight generations a year.


You can reduce a book louse infestation by 50% using very simple physical control methods. By lowering relative humidity, getting rid of mold, and properly storing books, boxes, and other vulnerable objects, you can eliminate many conditions that promote book lice development.


1. Install a vapor barrier under the ground floor if you have a dirt floor basement or a crawl space.

2. Make sure that your dryer’s outlet hose is equipped with a valve and is in good condition and dust free.

3. Always store cardboard boxes, books, and other vulnerable objects about a foot off the ground. Never put them directly on the floor.

4. Eliminate sources of stagnant water around the foundations and in crawl spaces.

5. Clean window frames. They often harbor dead flies, which can serve as a food source for book lice.

6. Repair plumbing leaks and recaulk around the bath, shower, and sinks if necessary.

7. Alternate areas where you store and hang dry clothing.

8. In new buildings, turn on the heat for several days in rooms where you have a book louse problem. This will help dry out damp walls and wood that is still green.

9. Freeze or heat treat infested items.

Please note. Freezing and heating can damage some objects that are sensitive to abrupt changes in temperature.

10. Remove leaf litter and other debris from around foundations and ground-level windows. Apply a residual insecticide on window frames

11. Repair breaks in the roof, air vents, gutters, and skylights.
12. Plug cracks on the inside and outside of foundations.

13. Never store items directly against the wall. Make sure there is 15 to 30 cm between the items and the wall.

14. Store firewood 30 to 45 cm off the ground. It is also a good idea to cover firewood with a tarp. If possible, dry the wood on a covered porch or in the garage or other shelter before bringing it into the house.

15. Regularly replace onions, potatoes, and other food products stored outside the refrigerator (if applicable).

16. Remove weeds next to the building and prune nearby trees that create a lot of shade. Shady areas promote the growth of mold, lichens, and mushrooms that are excellent sources of food for book lice.

17. Remove any wasp and/or bird nests from the building.

You can also consult an architect about the building’s structure and foundations. He or she can suggest solutions if you have serious condensation and mold problems.

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