Oak processionary moth

Oak processionary moth (Thaumetopoea processionea,OPM) is a pest that presents a hazard to oak trees and human health. It was accidentally introduced to the UK in 2005 after spreading from southern Europe as far north as Germany aided by the live plant trade and climate change. The OPM caterpillar lives and feeds on oak trees and can be recognised by their habit of moving in a nose-to-tail procession along tree branches. The caterpillar feeds on oak leaves and in large numbers can cause major defoliation, weakening the tree and making them vulnerable to other pests and diseases. The hairs on the caterpillars contain an irritating and toxic substance that can cause skin irritations and an allergic reaction in humans and animals. Contact usually occurs through touching the caterpillars or their nests or through contact by wind-blown hairs.

The main OPM outbreak area is largely confined to West/South-West London and Elmbridge/Spelthorne in Surrey (discovered 2006) where efforts are being made to limit its spread and impact. Further outbreaks have been identified in Pangbourne in West Berkshire (2010) and Bromley and Croydon in South London (2012). The main approach to control is the application of insecticides, either administered from the ground or by helicopter.

For more information see: http://www.forestry.gov.uk/oakprocessionarymoth