Further work to tackle the infestation of a moth species in Hertsmere is to begin in April.

Forty-eight trees found by council officers to have had oak processionary moth nests are to be chemically sprayed as a warning to the public to keep away.

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

Last July, Hertsmere Borough Council contractors removed and safely disposed of nests and caterpillars across it parks, after surveying 1,350 oak trees.

The survey showed 48 trees across 16 council sites had oak processionary moth nests, after the moth was first reported at three council-owned sites in May 2020.

Between April and June, contractors will chemically spray infected trees, in accordance with the Forestry Commission’s statutory plant health notices.

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 have a legal obligation to carry out the chemical spraying of infected trees, but will work hard to ensure this is carried out with minimal disruption to park users.

"We have taken the first step by removing the nests and are following that up with chemical spraying to try to control and limit the problem in Hertsmere.

"We installed signs in infected parks to warn park users of the risks of the oak processionary moth. Our advice remains 'spot it, avoid it, report it'."

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.

Anyone who sees an oak processionary nest or caterpillars in a council park should report them immediately on 020 8207 2277 or email customer.services@hertsmere.gov.uk or contact the Forestry Commission using its Tree Alert online pest reporting form.