Parasitic "hitchhiking" moths, which infect and destroy the leaves of conker trees, are moving north and could soon invade Scotland.
The horse chestnut leaf-mining moth, which originates in the Balkans, was first recorded in London in 2002 and has spread throughout England and Wales.
Dr Darren Evans, a reader in conservation biology at the University of Hull and co-founder of Conker Tree Science, said "it's only a matter of time" before the species expands further north into Scotland.
The invader feasts on the leaves of conker trees, turning them brown, and causes them to drop in the late summer.
Dr Evans said "several million" of the caterpillars could be present on each infected tree, adding: "It looks like autumn has come early for the trees. When the leaves have been destroyed, they tend to drop early."
There is little evidence that the moths can kill conker trees but Dr Evans said there were fears they could "weaken the tree's immune system" and make them more susceptible to disease, including bleeding canker, a bacterial disease which creates leaking "legions" of liquid on the tree trunk.
The horse chestnut tree was introduced to Britain hundreds of years ago, before the Victorians began planting them in large numbers, particularly in parks.
Researchers are concerned the threat of disease has caused a reduction in the numbers being grown.
As autumn approaches, Dr Evans also warns the moths are "bad news for conker players", with evidence suggesting infected trees produce smaller conkers.
Anna Platoni, entomologist at The Royal Horticultural Society, said little could be done to combat the moths.
She said: "The moth caterpillars overwinter in the leaves under the tree.
"You can rake up, collect and burn fallen leaves in the autumn and that will reduce the population in the vicinity of your tree. But unless you've got a very isolated tree, then the next year likelihood is it will just fly back in from somewhere else."
But she added there was growing evidence that native predators such as dragonflies and birds are starting to recognise the moths as food, which may restore "balance".
Dr Evans said the leaf-mining moth was just "one of a growing number of invasive insect pests" spreading throughout UK woodlands, aided by climate change and extensive foreign trade links.
The Conker Tree Science project is urging people to record sightings of moth-infected trees on their website, to help track the spread of disease.
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules hereLast Updated:
Report this comment Cancel