Pine processionary moth : Observatree guides

The caterpillars (larvae) of the pine processionary moth (PPM) (Thaumetopoea pityocampa) can threaten the health of pine trees (Pinus species) by feeding on their needles. Large populations cause extensive defoliation of pine trees, leaving them vulnerable to attack by other pests and diseases, and less able to withstand adverse environmental events such as floods and droughts. Timber production and tree growth can be reduced as a result of attack. The caterpillars are also a significant public and animal health risk, as they bear toxic hairs which can cause itching skin rashes, eye and throat irritation and breathing problems. Hence it is important not to approach or touch the caterpillars, or their nests.