If you follow us on Facebook, Instagram or Twitter you may have spotted that we recently had a possible sighting of oak processionary moths near the horse trail that runs around Millennium Country Park, and had to shut a small section whilst the area was investigated. We’re happy to report that following advice from the Forestry Commission we were able to reopen the section near Marston Meadow within a few days.

Oak processionary moth are still in the area though, and can pose a danger to people who use local woodlands for recreation as well as the actual trees themselves. Ranger Lottie has put together the information below for anyone wanting to find out more:
What are oak processionary moths?

Oak processionary moths (OPM) are an invasive species, and the caterpillars are pests that usually only target oak trees. They feed on their leaves and can even fully strip trees of their bark, leaving them susceptible to other pests and diseases.

The tiny hairs found on the caterpillars can also be harmful to people and animals, and are so small that they can be carried on the wind for short distances - which is why we closed the section of the horse trail out of an abundance of caution, pending further investigation.

Contact with these hairs can cause itchy rashes on the skin, irritation to the eyes and throat, and occasionally breathing difficulties. People and animals can both be affected in they come into contact with these hairs. If you think you may have come into contact with an oak processionary moth you should see a pharmacist to treat any eye or skin irritation, or for more serious allergic reactions see your GP or contact NHS 111.

How to identify OPM

They are found almost exclusively in oak trees, and the caterpillars move in long processions as their name suggests.

They have a grey body and dark head and are covered in long white hairs.

They are often seen in big clusters and build distinctive nests of white webs (found on the trunk and branches not in the leaves). The nests can also rapidly become discoloured though, making them more difficult to see.

What to do if you think you see OPM
Spot it, avoid it, report it’ is the guidance on the Forestry Commission website, which also lists additional ID information, pictures and links to online reporting tools. As a minimum they advise the below:
  • do not touch or approach OPM nests or caterpillars;
  • do not let children or animals touch or approach nests or caterpillars; 
  • do not try removing nests or caterpillars yourself; and
  • avoid or minimise time spent under or downwind of infested oak trees, especially on windy days in summer.

If you think you might see OPM in any of our Community Woodlands please also let our ranger team know.


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