The Leaf Miner, Cameria ohridella, arrived in the UK in 2002 from Europe. The larvae mine within the leaves, causing widespread damage. Severely damaged leaves shrivel, turn brown and fall by late summer, well before the normal autumn season. While there is no evidence so far that this causes the tree itself to die, the reduced photosynthetic ability may affect growth and the cumulative loss  of stored food products may compromise long-term health.

Although it is often mistakenly reported that there is no remedy for this infection there is hope in the form of good cultural practice and recognised treatments. Raking up all affected leaves and disposing of them in the garden galvanised incinerator is the best procedure. This is a very old practice carried out for many years by gardeners to prevent disease over wintering and reinfestation of trees the following year.

Recents treatments have yielded excellent results from aerial and microcapsule tree injection applications. Where treatments have been applied in areas of recent outbreaks the treated trees have not contracted the Leaf Miner.

While other diseases affect the Horse Chestnut, this threat is aesthetically disfiguring and markedly reduces photosynthetic capabilities which is ususally the beginning to decline. It is important that the Horse Chestnut is not lost in the same way as the venerable Elm and that part of our landscape tradition is kept intact for future generations to enjoy. If you suspect an infestation, don’t let it go untreated.