Long before the arrival of autumn, the chestnut trees began to defoliate and continue to lose their leaves parasitized by the leafminer. Now is the time to act to limit its action next year.
In Europe, white chestnut or horse chestnut ( Aesculus hippocastanum ) have been severely attacked by the leafminer ( Cameraria ohridella ) since the end of the 1980s. This parasitic butterfly of uncertain origin and observed in the east of the France in 2000 quickly progressed to the point of invading practically the whole country from 2004.
The great availability of chestnut trees on French territory, the rapid increase in the populations of this pest (it is estimated that the leafminer has three generations per year in France and that the population is multiplied by ten with each generation) and the absence of predators specific make the struggle more difficult. Synthetic pheromone trapping only removes part of the leafminer moths. Today, the cheapest method of reducing populations remains the careful collection of dead leaves and their disposal.
The insect overwinters in the leaf blades that have fallen to the ground. Without this protection, he cannot survive. It is therefore important to systematically collect the leaves from under the tree and nearby as soon as the fall begins. And they must be destroyed, the best being incineration. Composting is not a solution to eliminate them.
To your rakes and vacuum blowers!
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