The oak processionary moth is a risk to human health. The larvae (caterpillars) are covered in irritating hairs that contain a toxin and contact with these hairs, or their inhalation, can result in skin irritation and allergic reactions. These problems are significant because the moth is often most abundant on urban trees, along forest edges and in amenity woodlands. Oak processionary moth is a native species of central and southern Europe, where it is widely distributed, but its range has been expanding northwards, presumably in response to climate change. It is now firmly established in northern France and the Netherlands, and has been reported from southern Sweden. More recently, colonies of larvae have been found in parts of London.

Their hairs can cause unpleasant skin, eye and throat irritations in people and animals.

You can help the Forrestry Commission control this pest so we can all continue to safely enjoy our parks and woodlands.

Please tell the Forrestry Commission if you see:

• processions or clusters of caterpillars in oak trees; or
• silken webbing trails or nests on the trunks or branches of oak trees

Remember to:

• keep away from the caterpillars and nests
• call NHS111 or see a doctor or vet for serious allergic reactions.

Nests or caterpillars in other trees are unlikely to be OPM and do not need to be reported.

Report OPM with Tree Alert at forestry.gov.uk/opm or This email address is being protected from spambots. You need JavaScript enabled to view it. or 0300 067 4442