Often, nutritional unbalances are not
exclusively due to the deficiency of a single element. In many species it is
indeed clear that, under certain soil or growing conditions, the shortage or
excess of a single element is easily identifiable, as is the case of iron
deficiency in citrus fruit when cultivated in certain pH conditions or with a
poor choice of pattern.
In most cases, however, the visual symptomatology of a physiopathy is hard to assign
exclusively to a single element. In such circumstances it is preferable to
speak in terms of nutritional disorders rather than deficiencies.
Table grapes are one of the cultivated species
that display the greatest incidence of these types of problems. Indeed, due to
a lack of technical know-how, they may initially be wrongly defined as
exclusive deficiencies of Nitrogen, Potassium or some other primary or
secondary macronutrient.
Following this line of deduction we can observe
various visual symptoms in distinct phenological stages, all originally
assigned to a deficit, excess, or mismanagement of nitrogen nutrition.
Nonetheless, upon further inquiry, the complexity of each of them is noted. We
can more specifically define four distinct types of disorders: Spring Fever,
Inflorescence Necrosis, Bunch-Stem Necrosis, and Mushy Berry.
