Public urged to report sightings of tree pest Oak Processionary Moth

The public is being urged to report sightings of the tree pest Oak Processionary Moth (OPM) caterpillars.

Oak Processionary Moth was first identified in London in 2006 and has since spread to some surrounding counties. The caterpillars and their nests contain hairs which can cause itchy rashes, eye and throat irritations, and should not be touched under any circumstances at any time. The greatest risk period is May to July when the caterpillars emerge and feed before pupating into adult moths.

OPM caterpillars feed on oak leaves and can increase trees’ vulnerability to attack by other pests and diseases, making them less able to withstand adverse weather conditions such as drought and floods. A government programme is in place to limit their spread from areas where they are present.

The pest is established in London and surrounding areas but the majority of the country is designated a Protected Zone, which means it is free from the pest.

The Forestry Commission, working in partnership with others, have an annual programme in place to tackle the pest, with an ongoing programme of surveillance, treatment and research.

Andrew Hall, Forestry Commission Operations Manager, said:

At this time of year, many people are enjoying green spaces and it’s really important for the public to be aware of the risk of tree pests like Oak Processionary Moth and to report any sightings via our TreeAlert website or by calling the Forestry Commission. This will help us with our programme of treatment and enables us to slow the spread of this pest.

Any sightings should be reported to the Forestry Commission via its Tree Alert online portal. Alternatively, people can email

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