AT THE beginning of September the horse chestnut trees usually start to change colour, with a few red and yellow leaves appearing on them. But this year large numbers of them are presenting a sadder spectacle, with all their leaves shrivelling and turning brown. These trees have been attacked by a moth, the horse chestnut leaf miner, whose tiny caterpillars live inside the leaves and feed on them.
The moth was first discovered in Greece in the 1970s, and appeared in London in 2002. Since then it has spread more widely, and this year’s attack is the worst yet. The dry weather helped the moths. But the Forestry Commission is urging people not to chop the trees down, since most of them remain healthy, with only their leaves affected in late summer. The plague should not reduce the number of conkers falling from the trees later this month.
Unfortunately, some horse chestnuts are also suffering from a disease called bleeding canker, which produces ugly, dripping lesions on the trunks. Some of these trees will die, while others will have to be felled if their branches show signs of falling off.
DJM