Production Practices and Quality Assessment of Food Crops. Vol. 1

6.5. Management of old orchards
Chestnut, an Ancient Crop with Future 141
Main problems with old orchards are the aging related with the lack of pruning.
Then, the trees begin to produce smaller nuts and to emite rejects from the roots
loosing the cultivar (Figure 18).
Traditionally, one third of the crown of the old trees are pruned each 8 to 10 years
(Figure 11). This allows a third in full production, a third beginning to produce
and the other third renewing. In some areas, this operation is accompanied by
regrafting old trees with a new cultivar according to the demand of the market.
To recovering an abandoned old orchard, first one must consider cutting back
the old trees in order to produce vigorous stumps for the grafting (Figure 19).
Excessive strong prunes accompanied additional grafting can often kill the old
tree (Figure 20).
In some areas as in Switzerland (Figure 21) or in Galicia old orchards are recuperated
as part of the traditional landscape.
7. PEST AND DISEASES
Two main diseases, ink disease (Phytophthora spp.) and blight (Chryphonectria parasitica)
threaten chestnut. The most important insect pests are the weevils Balaninus
and Laspeyresia. In Asia, gall wasp is considered a very important pest in Japan
and Korea, and recently also in the United States.
Figure 18. Abandoned orchard in Galicia.