A combination of an exotic pest and a killer disease could threaten to wipe out the UK’s conkers and horse chestnut trees within 15 years, it has been reported.
The horse chestnut leaf miner moth, which first came to the UK in 2002, and the bleeding canker disease, are affecting Britain’s population of horse chestnut trees, while saplings are no longer being planted as they rarely survive longer than five years, the Telegraph reported.
The moth’s larvae effectively eat the trees’ leaves from the inside out by mining them, which destroys the leaf tissues, causing them to turn pale or brown. This has an impact on the trees’ ability to photosynthesise and their overall health. It also has an impact on the size of the conkers grown on the trees, which are smaller usual.
In addition to this, the trees are becoming infected with bleeding canker, a fungal disease that causes the trees to be ooze a black liquid and can cause the trees to eventually die.
Professor Robert Jackson from the University of Reading told Sky News: "We have a major disease epidemic (bleeding canker) and pest (leaf miner) sweeping through the UK population of trees.
"Most plant populations have some resistant individuals whose immune system can stop the infection, so we might see some trees survive, especially in woodlands,” he said.
Mr Jackson said the situation is looking “bleak” at the moment, adding: "Really we need to assess the population to see how resilient it is over time to see if it can survive."
Dr Glynn Percival, manager of the Bartlett Tree Research Laboratory at the University of Reading, told Horticulture Week: "I don't think the prognosis is good at all, unless we find something to control leaf miner. In trees that have leaf miner we do get an increase in the severity of bleeding canker because they have so little energy to defend themselves.
"Horse chestnuts have got maybe another five years unless we get the issues under control. The trees are living off their own natural resources. They're brown and crispy when everything else is green. No energy is being produced.”Reuse content