In the warehouse, chestnuts are usually subject to high temperatures so as to remove worms and to prevent the fungi attack. Later on, moisture must be reduced.

Chestnuts have the disadvantage of the worms attack, and for that reason some warehouses treat chestnuts with pesticides to kill them, although due to the residues problems every time there are less producers that use this treatment. Some companies make the curing with hot water at 50ºC for about 45 minutes. This treatment is also beneficial to control the conservation fungi and to remove defective fruit, since the fruit that floats has worms inside. Nevertheless, not all the damaged fruit is removed, since in some of them the worm has not been completely developed.

Later on they are air dried, sundried or subjected to other procedures until they lose 60-70% of moisture, in such a way that the produce lasts for years.

The chestnuts are attacked by worms and fungi.

The main problem for chestnuts are the worms.

Chestnut worm - These insects belong to the Balaninus elephas Gyll species, that lay their eggs on the developing chestnuts, and Cydia Splendana Hb. or Laspeyresia splendana, that lay them on the leaves. The larvae of both insects penetrate the fruit and they develop inside them. The adults get out when the chestnuts are already mature and drop. The chestnuts infected have nibbled bases, the surface shows bulky longitudinal grooves and when pressed with the fingers they are softer than the healthy ones. When worms go out they make some holes, that are smaller in the case of the Cydia. It is necessary to select the chestnuts at the moment of harvesting and to destroy those infected before the worm leaves the fruit.

The fungi that affect chestnuts during their marketing are Rhacodiella castaneae, also known as black rot or Phoma endogena.