The caterpillars of the Oak Processionary Moth (a close relation of the Pine Processionary Moth, commonly found in Spain and Portugal) present a danger to people and animals as well as oak trees, and are now in the UK.
The moth arrived in Britain in 2005 and it’s caterpillars threaten the health of several species of oak trees because they feed on the leaves. Large populations can strip bare large parts of oak trees, leaving them vulnerable to attack by other pests and diseases, and less able to withstand adverse environmental events such as drought and flood.
The danger to people and animals is caused by their thousands of tiny hairs, which contain an irritating substance called thaumetopoein. Contact with the hairs can cause itching skin rashes and, less commonly, sore throats, breathing difficulties and eye problems. This can happen if people or animals touch the caterpillars or their nests, or if the hairs are blown into contact by the wind, as the caterpillars can shed the hairs as a defence mechanism. Ingestion can cause a strong allergic reaction.
The caterpillars are easily recognised by their distinctive habit of moving about in late spring and early summer in a nose-to-tail procession, from which they get their name, and the fact that they live, almost exclusively, oak trees. They build distinctive white, silken webbing nests on the trunks and branches of oak trees and leave white, silken trails on the trunks and branches in early summer (do not touch either!). These nests and trails become discoloured after a short time, and more difficult to see as a result.
At the moment they’re just in the South East, emerging in oak trees around London, Surrey and Berkshire, so it’s worth being vigilant if you’re visiting any of those areas.
While these caterpillars are not in the Stroud area, if you think your pet has touched or eaten anything that has caused an allergic reaction, please call us on 01453 752555.