Overview
The oak processionary moth (OPM) (thaumetopoea processionea) is a southern European species that was accidentally introduced into the UK in 2005. Early cases were recorded in and around southwest London. It is now present in the whole of southeast England. It lives on oak trees and poses a risk to human and animal health.
Spread of OPM in Elmbridge and hotspots
The first cases of OPM were identified in Elmbridge following Forestry Commission (FC) funded surveys back in 2011 to 2012. A small number of sites were identified in the northeast section of the borough (East Molesey).
By 2020, OPM was established across the whole borough with any oak trees acting as potential hosts.
The current spread is patchy. There are hotspot areas around Weston Green, Ditton Common, Littleworth Common and Claygate Common.
Although OPM is well established, the number of nests in any Elmbridge area does not present a significant risk.
Time of year for OPM
Depending on the weather and leaf development, caterpillars are most active between April to August.
The greatest risk period is June to August. However, even when caterpillars have flown away, nests should always be avoided because they can contain thousands of shed hairs.
Eliminating OPM
OPM is established in the southeast and cannot be eradicated. In the absence of natural predators, the only existing preventative measures are centred around careful management.