Interdonato Lemon: Harvest Begins in October in the Sele Plain

In the Sele Plain, the harvest of the Interdonato lemon begins in October. This is one of the earliest ripening lemon cultivars in the Mediterranean. We are visiting the orchards of Lemon Group, where the trees, now in their fifth year, have reached an excellent balance between vegetative growth and fruit production, with an estimated yield of approximately 60–70 kg per tree.

Interdonato Lemon ready for harvest

Interdonato is a Sicilian lemon cultivar selected in the late nineteenth century along the Ionian coast of the province of Messina. Considered a natural hybrid between lemon and citron, it is also known as the Limone Nostrano or Liscione. In Sicily, harvesting can begin as early as the end of September, while in the Sele Plain it generally starts in mid October and continues throughout November.

Interdonato Lemon with very few Seeds

The fruit is elongated, with a pronounced nipple, a thin and only slightly rough rind, and few or no seeds. At the beginning of commercial maturity, it may still retain some green coloration, particularly at the ends. It is therefore not necessary to wait until the fruit has turned completely yellow, as external colour development mainly depends on declining temperatures, whereas the fruit may have already reached the appropriate level of internal maturity.

The orchard was established with a planting density of 5 × 3 metres, equivalent to approximately 667 trees per hectare. With production ranging from 60 to 70 kg per tree, the theoretical yield can reach 45 tonnes per hectare. These are promising results for a relatively young lemon orchard and are largely attributable to the training practices carried out during the early years of establishment.

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The initial pruning encouraged branching and the development of a well balanced, evenly distributed, bush shaped canopy. Once the tree has been properly trained, production pruning becomes straightforward. It consists of heading back branches extending into the inter row space, lowering excessive upper shoots by cutting them back to their point of origin, and moderately opening the central part of the canopy in a "palm of the hand" shape. The objective is not to hollow out the canopy, but rather to preserve a broad, well illuminated, and productive leaf surface. Under these conditions, pruning may require as little as five minutes per tree, equivalent to approximately seven to eight working days per hectare.

High yields are not the result of a miraculous fertilisation programme. Nutrition, irrigation, and foliar applications can support tree performance, but fruit production begins with the presence of fruit bearing shoots. Without shoots, flower buds cannot develop; without flowers, fruit set cannot occur; and without fruit set, there will be no lemons. Productivity is therefore primarily the outcome of effective canopy management that maintains a consistent balance between vegetative growth and fruiting from year to year.

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The trees are planted on slightly raised beds, with grassed inter rows and a double subsurface drip irrigation line buried at a depth of approximately 10–15 cm. The light textured soil promotes drainage, root aeration, and early vegetative growth, but it also requires carefully scheduled irrigation to minimise water stress and reduce the loss of water and nutrients.

Mild symptoms of mal secco, the destructive vascular disease caused by Plenodomus tracheiphilus, are also visible. Interdonato has demonstrated a reasonable level of field tolerance, as confirmed by studies on citrus germplasm, but it is not immune. The timely removal of infected branches, disinfection of pruning tools, and proper disposal of infected plant material remain essential management practices.

In a region traditionally devoted to forage crops, buffalo farming, and the fresh cut produce industry, lemon cultivation is steadily expanding. Interdonato represents a valuable production alternative, but high productivity cannot be achieved at harvest time alone. It is built progressively, one branch at a time, beginning in the very first years of orchard establishment.

 

Editorial Note

Original content by Dr. Vito Vitelli, Agronomist, prepared and enhanced with the support of artificial intelligence tools for educational, informational, and technical dissemination purposes.

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