Moth infestations in Hertsmere's parks under surveillance

The Forestry Commission will be undertaking surveillance of some of Hertsmere’s oak trees between February and March to investigate outlying oak processionary moth (OPM) reports from members of the public.

The oak processionary moth caterpillar and their nest can cause itchy rashes, eye irritations and, in severe cases, breathing difficulties in people and pets.

The moth was first reported in three council owned sites across the borough in May 2020.

Since then, the council has surveyed more than 1,350 Ooak trees across Hertsmere’s parks and open spaces and identified 48 trees across 16 council sites as having oak processionary moth nests.

In July, contractors, wearing protective clothing, removed and safely disposed of nests and caterpillars across our parks.

The greatest risk period is May to July 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.

Stock image of an oak processionary moth caterpillar

Councillor Seamus Quilty, portfolio holder for environment, said: "Since the oak processionary moth was first sighted in Hertsmere, our officers have surveyed a large percentage of our oak trees to determine the level of infestation and ensure the safety of park users.

"We are working with the Forestry Commission to tackle the OPM problem and implement proactive solutions to try to control and limit the spread in Hertsmere. The surveillance being conducted by the Forestry Commission is one part of that.

"We installed signs in parks where the oak processionary moth had been identified to warn park users to be vigilant. Our advice remains 'spot it, avoid it, report it'."

The contractors will be wearing hi-vis Forestry Commission vests and will carry a Plant Health Authority Card at all times when surveying.

Trees identified as having an OPM infestation will be sprayed with an orange ring.

Report any OPM nests on council land to 02082072277 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, by calling 030 0067 442 or emailing opm@forestry.gsi.gov.uk.