Nearly one thousand species of Psocoptera have been catalogued, the majority of which live outdoors, feeding on moulds and fungi.
Psocids become a pest when they invade homes - almost always linked with damp conditions.
Booklice Image Copyright - Aventis Environmental Science 1964. Reproduced with kind permission of Aventis Environmental Science. Psocids favour damp conditions. Biology Control Eggs are generally laid within foodstuffs when psocids are found indoors. Psocids are almost always associated with damp conditions and indeed require damp environments to survive.