Gardening

Chestnut diseases


The difficult situation of our chestnut trees


Unfortunately, even this year there is no good news from the chestnut harvest.
Visiting festivals and autumn events there is a general discomfort on the part of the organizers, due to the sharp fall in the harvest of chestnuts in their forests.
The situation for the chestnut tree, Castanea sativa, has been very difficult for about ten years, since the presence of a very dangerous insect in Italy was also ascertained.
The chestnut gall wasp, Dryocosmus kuriphilusYasumatsu, is a small hymenoptera, a sort of wasp originating from the East, arrived in Italy due to the scarce phytosanitary controls on imported materials, it spread in our woods with extreme speed.
Often when an exotic species is introduced into a new ecosystem, it does not find antagonists that can oppose it and if climate and food are favorable, nothing stops its development.
This is what happened to the chestnut gall wasp, which deposits its eggs inside the buds, from which galls develop that appear as green / reddish swellings. These damages cause a decrease in the vegetative development and above all of the fruit production.


Care and prevention




It is not easy to fight populations that attack entire forests, the struggle with chemical means is hindered by the vastness and typology of the areas involved.
Furthermore, the life cycle of the insect is long and for most of the time remains "sheltered" within the buds themselves in the form of a larva.
The biological fight is the one that can bring more results and the recent introduction in some territories like the Ligurian and Piedmontese of Torymus sinensis, a natural insect antagonist of the cinnipid, still leaves us some hope. The biological control plans do not have immediate effect, but aim to solve the problem in the long term. Introducing in natural ecosystems, a new species takes time, because it enters strongly into the territory and develops independently.

Chestnut diseases: Other diseases


From the northern regions there is also news of a very high presence of fungus, Gnomoniopsis (Discula) Pascoe, which causes rot within the fruit.
In short, the situation is anything but rosy and the only weapon is cooperation.
Anyone who has a chestnut grove must contact the mountain community to which he belongs to inquire about the precautions to be taken in managing his own forest.
It is very important to follow the directives of the bodies in charge and coordinate the interventions to increase their effectiveness.