Parasitic moths that kill conker trees on their way to Scotland
PARASITIC moths, which infect and destroy the leaves of conker trees, are moving north and will soon invade Scotland.
The horse chest nut leaf-mining moth, which originates in the Balkans, was first recorded in the UK in London in 2002 and has since spread throughout England and Wales.
Dr Darren Evans, a reader in conservation biology at the University of Hull and co-founder of the Conker Tree Science project, 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 diseases, such as bleeding canker. The horse chestnut tree was introduced to Britain hundreds of years ago and became fashionable in Victorians times when they were planted in lar ge numbers in parks.
Researchers are concerned the threat of disease has caused a reduction in the numbers being grown.
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 the 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”.