dangerous oak processionary caterpillars on infested tree

allergy animal are asthma background black branch brown butterfly caterpillar caterpillars causing close closeup control damage danger dangerous detail europe forest green hair hairs hairy hazard health human infection infested irritation larva lungs macro many natural nature nest oak outdoor park pest plant poison poisonous problem procession processionary processionea rash skin spring thaumetopoea threat toxic tree white wild wildlife