AN URGENT warning has been made over a swarm of toxic caterpillars invading the UK.
The bugs pose a serious health risk to people and can leave those who touch them with rashes and difficulty breathing.
The black caterpillars have venomous white hairs around their body
Where the critters can be found in the UK
Touching the caterpillars can leave people with red rashes
Oak processionary moth caterpillars might look cute but officials are asking the public to report any sightings and stay clear of touching them.
They are found in south east England – having been accidentally transported from Europe in trees for planting.
Oak processionary moth caterpillars and their nests of white silken webbing should not be touched under any circumstances, say the Forestry Commission.
The critters are covered in hundreds of white hairs which are venomous.
Touching the hairs can cause itchy rashes, eye and throat irritation.
The caterpillars have their name from the way they descend oak trees – in a nose-to-tail processionary form.
Not only are they dangerous to people, they also damage Britain’s beautiful oaks.
As they migrate along the oak, they feed on the tree’s leaves – harming its growth and weakening it.
That leaves it vulnerable to other stresses, like drought and disease.
Nests can be found in the trunk or branches of oak trees and are normally tennis ball-sized and white when fresh before turning brown as they age.
If you do find a nest or the caterpillars, officials advised never to try and dispose of them.
A warning has now been issued by the Forestry Commission urging the public to report any sightings to them.
Oak processionary moth project manager Andrew Hoppit said: “It is important those living and working in areas affected by oak processionary moth remain vigilant about the health risks they pose, when enjoying outdoor spaces, as we are entering the greatest risk period.”
The insect was first identified in London in 2006, and has since spread to surrounding counties.
Professor Nicola Spence, UK chief plant health officer, said: “Oak trees are an iconic and much-loved part of our British landscape.
“By reporting any sightings of the oak processionary moth to the Forestry Commission, we can all minimise the pest’s spread as well as reduce their impact on tree health.
“I would advise that members of the public living in London, the surrounding areas and Derbyshire, avoid any contact with the caterpillar and its nests, as this can cause irritation.”
Much of southern England has been conquered since the pests arrived in South West London on a shipment of trees in 2006.
The bugs have been detected across the capital, as well as in Surrey, Hertfordshire, Essex, Kent, and Berkshire.
The rate of the spread appears to have quickened in the last few years.
In 2022, the number of “attacks” topped 100 for the first time.
Some 225 people were poisoned by oak processionary moth hairs in 2022 — four times the 56 in 2021.
People can report sightings via the TreeAlert website.
How to identify oak processionary moths
THE caterpillars have black heads and grey bodies covered in long white hairs.
They are only about 2mm long when they emerge in spring, and tend to remain high in the trees until they are older and larger.
When they reach 1cm long, they develop the irritating hairs. They’re fully grown at 2cm long.
They usually move nose-to-tail in a procession, hence their name.
You may be able to see them on all parts of the tree – on the trunk, branches and leaves, and occasionally on the ground.
Nests are usually found in early summer, in the trunks and branches of oak trees at any height.
They are typically dome or teardrop-shaped, and range from the size of a golf ball to a rugby ball.
When fresh, the nests are white with white silken trails made by the caterpillars along the branches and leaves.
But the nests soon become discoloured and brown, making them harder to spot.
The caterpillars travel in a nose to tail fashion
The Forestry Commission has released a warning as the country heads into summer