The horse chestnut leafminer (Cameraria ohridella
) is a species of moth
, a pest that infests
trees and has recently spread explosively throughout central Europe
. It was first
observed near lake Ohrid
in 1984 and christened Cameraria ohridella
in 1986. Since it is not hindered by specialized predators or parasites, the leafminer has spread
quickly and once it reaches a region, it infests all horse chestnut (Aesculus hippocastanum
trees to a shocking degree. Red horse chestnut (Aesculus carnea
) and red buckeye
appear to be more resistant (or less favoured by the leafminer).
The moth's larvae live inside the
tree leaves, eating through the tissue and creating small tunnels or "mines" (thus the name "leafminer").
After 3 to 4 weeks, the larvae spin cocoons from which new moths emerge. In a hot, dry summer, three or more
such generation cycles can occur! This leads to such severe infestation that the damage results in
complete defoliation of the trees in late summer. Even before that, the leaves turn brown and
unsightly, which is the main problem, horse chestnuts being popular ornamental plants. Fortunately,
the infestation does not appear to kill the trees, although it of course hinders their development.
So far, no effective way to combat the leafminer has been found, although the yearly infestation can be
delayed and reduced by removing all dead foliage from the vicinity of the trees, since the leafblighter
uses it to hibernate during winter.