Booklice are tricky to control with insecticide because they have a tolerance to permethrin and probably to other pyrethroids. The best product to use is diatomaceous earth. This is a natural product that works by dehydrating the insect to the point of death.
Remove the conditions that booklice need to survive. Address the damp by ventilating rooms, using a dehumidifier, mending any leaks etc. Vacuum regularly to physically remove the pests and seal up any cracks that could provide potential harbourage with caulk.
Booklice (psocids) are very small, soft-bodied insects that are quite common and perfectly harmless. They are similar in appearance to the common headlouse, hence their name, but they are not a louse. Neither are they associated with dirt or poor hygiene.
Booklice have an incomplete lifecycle which means they go through nymphal moults to become adults
All adults are female and lay relatively large eggs at a rate of about 2 per day. Eggs are laid in crevices, about 100 per female.
The optimum temperature for this species seems to be between 25º and 30ºC when a complete lifecycle can take three to four weeks. A much slower development takes place at lower temperatures.
Booklice thrive in damp, warm conditions and are consequently more prevalent in spring and summer.