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In this third part, dedicated to the care of diseases of fruit plants, we will examine the main causes of damage to the cultivation of wine and table grapes and the main symptoms will be indicated, with useful remedies for the correct cultivation of this plant, among the most widespread on an agricultural and amateur level.
The main reasons for the widespread diffusion of diseases are to be found among the millenary origins of cultivation in our environments and in equal measure from the Mediterranean vocation or typicality, given by the rusticity and adaptability to almost all our climates.
The success of the cultivation of the vine as of all plants is the result of a set of ideal conditions of equilibrium including: the agronomic technique, the correct management of fertilization and defense, and, as for other crops, it is important to constantly monitor the their state to be able to intervene promptly to contain the spread of pathologies and encourage a correct development.
The general rules already indicated for the fight against the adversity of other crops such as: "prevention is the best cure" and that "good nutrition is the best resource for resistance to diseases" are more than valid in viticulture and for this reason, at in order to recognize from the first symptoms the pathogens or the cause of the vegetative block the adverse causes are grouped in tables with diseases and the damages caused.
Adversity and care
To illustrate the various problems that damage the vine, the different causes can be grouped into: environmental, parasitic and fungal diseases, insect and animal damage.
1) non-parasitic diseases: nutritional or environmental.
All the vines need neutral, well-drained soil, fairly well equipped with fertilizing elements, organic substance, and moisture in moderate soil in order to grow and produce regularly.
Although the vine is a rustic species, the lack of a soil suitable for cultivation and lack of nutrients due to the soil causes a general deterioration of the plant, with consequences that negatively affect the whole physiology of the plant, reducing production and the quality of the product for food values if table grapes or oenological value and shelf life are used if wine is made.
Plants that are weakened due to nutritional deficiencies are then more affected than others by parasitosis, because their resistance to combating diseases is reduced.
The vines with deficiencies show specific symptoms such as yellowing, reddening, leaf desiccation, poor flowering and fruit set, or bunches with small, deformed berries with a sharp taste.
Depending on the type of nutrient that the plant lacks, the main causes are explained in the following table:
on the plant
on the bunches and enological reflections
generalized plant and leaf yellowing
more pronounced in basal areas. Stunted vegetation
with poor flowering.
small acidulous production and berries
bronze-purplish leaves, little growth
and poor flowering.
very slow or incomplete, productive shortages e
sparsely stored grapes and wine.
leaves can become yellowish
on vines with white or brown grapes - reddish on
red vines. In severe cases they follow dries
of the flaps with U-shaped curvature. Poor lignification
of fabrics and greater sensitivity to cold.
small, with sour berries, poorly colored
and sugars. Wine with low alcohol content and low
basal leaves turn yellow and dry out
central rib and can fall early.
production reductions caused by the desiccation of the
rachis and berries. Poorly sugary must.
leaves accentuated with yellowing and boiling.
laminae of young leaves mainly dry up
on the margins and on the apex.
small with deformed berries. Poorly aromatic wine.
progressive from the apices to the bottom of the plant with
leaf desiccation in the most severe cases.
No or very poor flowering.
irregular with poor production. poor quality
on berries and wine.
on the plant and on the bunches
pathological of mushrooms
leafy oil stain, in correspondence of the
which, on the lower edge, appear molds
white. Bunches completely covered with mold
white felt spots on leaves and berries
crack or crack.
or white mal
leaves and young clusters appear gray mold
ashes that later on dry up the organs.
Sometimes attacks appear only at maturity,
with molds located only on the center of the bunches.
gray of the bunches
on young shoots like lesions or bruises. leaves
or bunches that dry up.
or cracking of the branches
on the plant and on the bunches
that with their stings on the leaves produce
silver discolorations and deformations.
with dark green elytra they feed by pricking
or digging the leaf. Following the erosions the
leaf rolls up in the shape of a cigar and within a
this the female lays her eggs.
caterpillars or larvae of butterflies that they destroy with the
their erosions either the young shoots or invade
the berries at the beginning of maturation.
sucking butterflies that prick young leaves
or buds. The affected organs present curl up
with tawny or golden colors.
tiny spiders that they cause with their bites
on the yellowing leaves that later dry up
and fall early. They are very mobile and when
they massively attack the plant they also produce
or red or yellow spiders