A Technical Report from The Bartlett Tree Research Laboratories
Oak processionary moth (OPM) isa defoliating pest of English, Sessile and Turkey oaks. Infestations of OPM caterpillars were first found in London in 2006. The larvae (caterpillars) will also feed on the foliage of hornbeam, hazel, beech, sweet chestnut and birch. Oak processionary moths present a risk to human health. The older caterpillars (3rd to 6th instars) are covered in irritating hairs that contain a urticatingtoxin (thaumetopoein). Contact with these hairs, or their inhalation, can result in skin irritation (dermatitis) and allergic reactions (rashes, conjunctivitis). Only individuals with specialised training should attempt to control OPM.