Warning over oak processionary moths in Hertsmere parks

The oak processionary moth (OPM) has been discovered in a number of parks and open spaces across the borough.

The caterpillars and their nests are deemed a “hazard to human and animal health” by the Forestry Commission. Their hairs can cause itchy rashes, eye irritations, allergic reactions and, in severe cases, breathing difficulties in people and pets.

Ian Kershaw, Hertsmere's head of street scene, said: ”During the warm weather our green spaces are a welcome retreat for residents to spend time outside.

"Unfortunately, oak processionary moths have been sighted in some Hertsmere parks, so our message is to be vigilant, especially with young children who may be exploring trees this summer.

"Our parks team is working to manage oak processionary moths in our area and will be putting up safety notices in those parks affected to warn the public.

"If you discover an OPM nest or caterpillar, we ask that you 'spot it, avoid it, report it'."

The public are urged never to try and dispose of the nests themselves. The caterpillars should not be handled or approached.

People can use the online reporting system ‘TreeAlert’ to identify and report the oak processionary moth.

Oak Processionary Moth warning poster from the Forestry Commission (Image: Supplied by Hertsmere Borough Council)
 

Reporting OPM 

If you see any oak processionary nests or caterpillars (OPM) in a Hertsmere council park you should report them immediately on 020 8207 2277 or email customer.services@hertsmere.gov.uk

If they are on a privately owned oak tree, report them to the Forestry Commission using the Tree Alert online pest reporting form. If you cannot use Tree Alert, you may report them by telephone on 0300 067 4442 or by email at opm@forestrycommission.gov.uk.

For more information on the oak processionary moth, including distribution maps and more detailed guidance on treatment visit www.forestresearch.gov.uk/treealert or www.forestresearch.gov.uk/opm

This time of year is when the caterpillars emerge and feed before pupating into adult moths, but nests, even old ones, should not be touched at any time.

The nests are typically dome or teardrop-shaped, ranging in size — from a ping pong ball to as large as a rucksack. They are white when fresh, but soon become discoloured and brown.

The caterpillars have black heads and bodies covered in long white hairs and are easily recognised by a distinctive habit of crawling in large groups, nose-to-tail forming long lines on or around oak trees.

Ian Kershaw added: “Officers are aware of the caterpillars on a number of council sites across the borough, which we are dealing with in the correct manner to minimise harm to the public. 

“We have conducted a survey of all our high use locations within the borough to establish the current spread alongside a strategy to remove existing infestations. This will not involve removing any infected oak trees on council land.”