The pine processionary caterpillar Thaumetopoea pityocampa (Lepidoptera: 
Notodontidae) is considered to be a serious pest of medical importance. The hair 
on the dorsum of the last instar larvae of the moth may cause urticarial 
reactions (erucism) as well as eye problems and temporary blindness. In Israel, 
the pest occurs in all pine plantations as well as on ornamental pine trees in 
urban areas. The biology, ecology and management of the moth population are 
discussed as well as the mechanism of action of the urticarial hairs and their 
medical significance. Awareness of the life cycle and ecology of the pest may 
reduce the contact of the population with the urticarial hairs and prevent the 
morbidity caused by it.