The oak processionary moth must not be touched in any circumstances
The Forestry Commission is calling on the public to report any sightings of the oak processionary moth caterpillars as their hatching season commences. The “greatest risk period” has been announced, starting from May 28.
These caterpillars are known for defoliating trees and can also have adverse effects on human health. The public is advised to not touch the caterpillars under any circumstances.
People are also warned against handling or disposing of the nests themselves. Contact with the caterpillars’ white hairs or their nests can lead to painful skin rashes, as well as eye and throat irritation.
Should you encounter these caterpillars, it’s advisable to maintain a safe distance and report the sighting through the TreeAlert portal.
Sightings are most common in South East England. Dr Edward Straw, Forestry Commission Oak Processionary Moth Programme Manager, said: “We’re already receiving reports of homeowners being affected by the caterpillars, coming out in painful rashes, and it is important those living and working in areas affected by oak processionary moth remain vigilant about the health risks they pose.”
Professor Nicola Spence, UK Chief Plant Health Officer, has also issued a warning.
He said: “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.
“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.”
The caterpillars are named for their distinctive behaviour of moving in nose-to-tail processions up the trunks of oak trees, sometimes creating an arrow-like pattern on the bark.
They munch on the leaves, which hampers the growth of the oaks and makes them more susceptible to other stressors such as drought and disease.
The oak processionary moth is an alien species in the UK. It was first identified in London in 2006 after being inadvertently introduced from Europe via imported trees.
In recent times, the moth has been expanding its presence across England, with new infestations detected in areas previously believed to be unaffected as recently as last July.
The milder conditions this spring have led to a faster growth rate of the moths compared to past years, thus advancing the peak risk period for both the oak trees and the public.