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Nutritional disorders


Dietary deficiencies *

Like many cultivated plants, the melon needs a variety of mineral elements to ensure its growth throughout its development cycle. When they are provided in excess or they are lacking, nutritional disorders occur ( nutritional disorders ).

In addition to not always being easy to manage, its fertilization can be influenced by various parameters:
- the richness and balance of the soil in fertilizing elements ( soil analyzes are therefore essential );
- the type of melon cultivated and the variety chosen;
- the density of plantation;
- the mode of production;
- the nature of the irrigation system and its conduct;
- and any other factor disrupting plant growth.

It is therefore not uncommon to be confronted in the field with plants suffering from deficiencies or an excess of nutrients. These conditions are part of the non-parasitic diseases and grouped together under the terminology “ nutritional disorders ”. The latter appear quite frequently on melon by yellowing of variable nature and distribution on the plants (Figures 1 and 2).

Note that in cucurbits, although the fertilization of cultivated species has similarities, they do not show the same sensitivity to deficiencies. For example, zucchini, melon and watermelon are quite sensitive to boron and molybdenum deficiencies, and less sensitive to iron, manganese and magnesium deficiencies. On the contrary, cucumber exhibits iron and manganese deficiencies more easily, and much less boron and molybdenum deficiencies.
The following table summarizes the symptoms observed in the event of a few major deficiencies in melons.

Deficiencies Symptoms

Calcium (Ca) Note that the manifestation of vitrescence melon is influenced by an unbalanced mineral diet in calcium and potassium.

Bore (Bo) Young leaflets near the apex are slightly chlorotic, necrotic and fragile and tend to deform, curl. Plant growth is slowed down.
Decrease in the organoleptic quality of the fruits.

Fer (Fe) Interveinal chlorosis of young leaflets beginning at their base and gradually reaching their tip. Ultimately, the tissue can turn white and chlorosis can spread to the entire plant.

Magnesium (Mg) Interveinal chlorosis beginning at the periphery of the lower leaf blade. At the end of the evolution, the yellowed tissues end up necrosis while the veins tend to keep their green color.

Nitrogen (N) The lower leaves are pale green, the older ones show more yellowing and may necrode and drop. Plant growth is limited.

Molybdenum (Mo) The growth of plants and their root system is very reduced.
Yellowing, bleaching and necrosis of leaf blade tissues at the periphery of the leaf blade of old leaves with the edge rising. This deficiency is very damaging in melons.

* Note that currently, when we talk about deficiency, we often tend to equate true deficiencies with induced deficiencies. The real deficiencies (missing from the ground) are increasingly thin on the ground (especially for trace elements); their diagnosis visually is very difficult because, with some exceptions, the symptoms they cause are discolorations, more or less intense yellowing of the leaves, very difficult to assess by a non-specialist.
We are often dealing with induced deficiencies (elements present but not available), which does not facilitate their diagnosis; in addition to determining the nature of the deficiency and possible confusions of symptoms, the cause (s) should be investigated. These can be found under the following conditions: reduced development or poor condition of the root system; too low soil temperatures; excessive night temperatures; excessive or unbalanced manuring often resulting in antagonism between elements; incorporation of fermentable organic matter; low light; imperfect control of irrigation (excess asphyxiation, lack of water); heavy leaching; nature of the soil very calcareous or too acidic; excess heavy metals in the soil.

It should be remembered that deficiencies occur particularly in crops that have been amended empirically, in the absence of soil or nutrient solution analyzes. When you are faced with this type of symptoms, you should not hastily conclude that there is any deficiency without consulting a specialist and having carried out the necessary analyzes (physical, chemical) of the soil, of the vegetation ...
Excess salinity
Last change : 04/30/21
  • Author :
  • D Blancard (INRAe)
Figure 1
Figure 2
Figure 3