May 1st, 2018 by Chris Chapman

A worsening infestation of toxic caterpillars that cause asthma attacks, vomiting and rashes has spread throughout London and the south east of England, the Forestry Commission has warned. Oak processionary caterpillars almost always make nests in oak trees Oak processionary moth caterpillars, which will not turn into full-grown moths until late summer, are covered in toxic hairs that can cause a variety of ailments, including fevers, dizziness, vomiting, rashes, eye irritation and asthma attacks. The caterpillars move in large groups (or ‘processions’) and will often shed their hairs which can be blown by the wind, causing harm to anyone who comes into contact with them. While the caterpillar is only alive for a few months through the spring and summer, these hairs can remain active for up to five years. Sightings are so far limited to suburbs and woodland across south east England, however the Forestry Commission warns that conditions are ideal for the caterpillars to spread further. The caterpillars are active throughout spring and into summer, when they cocoon themselves and turn into moths As the name suggests, oak processionary moth caterpillars are almost always found in oak trees, however they can survive in most wooded areas. They can be identified by the long white hairs that cover their bodies, and by the processions they move in, which tend to be straight lines or arrow formations. Any suspected sightings of the oak processionary moth caterpillars should be reported to the Forestry Commission. Members of the public are warned not to go near or touch the caterpillars as they are highly toxic.

How to Identify an Oak Processionary Moth Caterpillar Infestation

• They will usually cluster together in large colonies, or travel around in nose-to-tail formations
• They cluster on oak trees, specifically around the trunk or branches, not in the leaves
• Their nests are spherical or teardrop-shaped, and are made of silk webbing
• The caterpillars themselves are covered in long white hairs

What to Do with an Oak Processionary Moth Caterpillar Infestation

• Report the sighting to the Forestry Commission even if you can only find a nest, but no caterpillars. The caterpillars will still have left their toxic hairs around the nest which will need professional removal
• Take precautions to keep children and animals away from the caterpillars
• Take extra precautions around people who suffer from breathing conditions, such as asthma
• Keep clear of the affected area until the caterpillars and nests are removed
• At the end of winter/start of spring, treat oak trees with a natural pesticide like Pyrethrum to deter caterpillars from infesting