Leaf raking against the Horse Chestnut Leaf Miner Moth

November 8 is Day of Action “Save our Horse Chestnuts”

by Michael Smith

A nasty parasite is already for a number of years been plaguing the white-flowering Horse Chestnut. In Germany this pest has now reached all areas and also in Britain it is spreading like wild fire. From its arrival in 2001/2002 in the Wimbledon area of South London it has now spread to most parts of Southern Britain.

This parasite is bringing an early autumn to our beloved Horse Chestnut, the tree that brings fun and games to the children of the British Isles, in the form of the conker game (as long as the schools and authorities try not to ban it) and simply collecting the chestnuts. As children we also made little animals and people and little baskets out of the conkers. In August already all the leaves have dried out and it looks like Fall has arrived.

The parasite responsible for this, the Horse Chestnut leaf miner moth (Cameraria ohridella), has no natural enemies, neither in Germany nor in the British Isles. It was always said that a wet summer and wet winters would kill the moth and the eggs of the moth that overwinter in the fallen leaves but, alas, this does not seem to happen for the last two summers in Britain were very wet and the moth still has caused great damage again in 2008. Despite intensive research no antidote has as yet been found against this damaging insect.

The until now only effective countermeasure against it is to collect all the fallen leaves as soon as possible and to burn them in a sanitary way. This is the only way to prevent that the eggs of the moth that overwinter in the fallen leaves turn into larvae.

In Germany the Schutzgemeinschaft Deutscher Wald calls already now for a number of years upon communities and cities to take part in the collection action and to encourage their residents to take part in this.

The city of Essen in North-Rhine-Westphalia (Germany) is leading the way here in that sacks are provided free of charge for residents to be able to collect the leaves, which are then collected by the municipality and burned in a waster incinerating heating plant.

Those communes that have been taking part in this action of collecting of fallen leaves for a number of years now can prove that it works in that their Horse Chestnuts are once again green until at the right time in late autumn.

Collecting and burning the fallen leaves is the only way to rid ourselves of this pest that so badly affects our Horse Chestnut.

While the Horse Chestnut Leaf Miner Moth not necessarily causes the death of the trees it will, over time, however, weaken the trees and allow other pathogens and parasites to destroy the trees.

© M Smith (Veshengro), September 2008
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