Competitors swing their conkers during a match at the World Conker Championships, in Southwick, central England October 9, 2016.© Phil Noble / Reuters/Reuters
Never mind Brexit, the falling pound or the sad state of England's soccer team. Britain is facing a far more pressing concern: fewer conkers.
The hard shiny nuts are an iconic feature of autumn in Britain and they have been used by children for centuries to play "conkers," a game in which players thread nuts on string and then take turns bashing each other's conker (there's even a World Conker Championship).
But now conker trees, known as horse-chestnut trees, are being threatened by a tiny moth and some experts fear that the species could be wiped out in a couple of decades.
Horse-chestnut trees are loved for their size and near-perfect shape. But they are not native to Britain. They were brought here about 200 years ago from Greece and Macedonia and planted in gardens and parks mainly in England.
In the past 14 years, trees across the country have been infested by the leaf-mining moth, which is about the size of a grain of rice. Adult moths lay up to 40 eggs on each tree leaf and their larvae eat the leaves from the inside, creating small cavities or "mines." Theses moths, which live only on horse-chestnut trees, don't kill the trees, but they weaken them, making them susceptible to other diseases and unable to reproduce. And that means fewer, or smaller, conkers.
"It's bad, yes," said Michael Pocock, a researcher at the Centre for Ecology & Hydrology. The threat from the moths "means that we are likely over the next decade or two to see fewer horse chestnut trees in this country," he said.
Glynn Percival, manager of the Bartlett Tree Research Laboratory at the University of Reading, told Horticulture Week magazine: "Horse chestnuts have got maybe another five years unless we get the issues under control."
Scientists believe that the moths arrived in London via human transport around 2002. The moths have since spread rapidly, as far west as Wales and into northern England with reports saying they have reached Scotland.
Researchers are trying to understand why the moths have had such an impact in Britain but appear to do far less damage on the same trees in Greece or Macedonia. One possible explanation is that there are fewer threats to the moths in Britain, such as other insects or birds that feed on them. Or the trees in southern Europe could be hardier. Either way, there is little researchers can do to stop the spread of the moths, other than track their progress.
Dr. Pocock and a colleague, Darren Evans, have set up a community science effort called the Conker Tree Science Project to find out the scope of the damage. The project, launched in 2010, encourages volunteers to photograph horse-chestnut trees in their area that have been infested. So far, 8,000 people have participated.
The results "will prepare us better for when a similar pest comes in, in the future, on maybe a different species of tree, and we can understand more, and be more prepared, about stopping its spread," Dr. Pocock said.
He added that the project is also testing claims that trees infested by the moths for many years have developed a kind of resistance. There have also been suggestions that the moths spend the winter in dead leaves underneath trees, meaning that if leaves were cleared away, the moth population would decrease.
The project has already yielded one scientific paper and turned into something of a personal crusade for Dr. Pocock, who spends his working days concentrating on the impact of environmental change on ecosystems. "It's been my passion, actually, in many respects," he said. "And it seems to be something that seems to have caught people's attention."
Paul Waldie