Main pests and their control
The shelter is an important protection for your cuttings, because it takes away the main vine pests and the damage they cause and possible methods of containment, can be summarized as follows.
Grapevine
downy mildew (Plasmopara viticola): This is a fungus that affects the
leaves, shoots, inflorescences and bunches; favored by high humidity and
rainfall, spring temperatures> 10 ° C in summer and 20-26 ° C. The
spring infections manifest as oil spots on the leaves, while massive
attacks causing chlorotic spots summer mosaic-cluster on a deformation
"S" of the spine, the grapes undergo severe dehydration, dry up and
become purple. Attacks on clusters are serious because they can cause declines quantitative and qualitative data on the grapes. In
spring infections (on the leaves) they start when they occur
simultaneously climatic conditions known as the "rule of three tens",
summarized as follows: the minimum air temperature stabilizes at 10 ° C,
the shoots of the vine reaches 10 cm long, the rain falling in the previous 24 hours must be at least 10 millimeters.
To
counteract the blight recourse is to the use of fungicides coverage
(products based on copper), equipped with a preventive action, they act
outside of the tissues and are not able to block infections in act, and
of systemic fungicides ,
which exert a curative action: in fact they are absorbed by the plant,
avoiding the leaching and translocated in all its parts. Generally
are used together as the systemic products, if applied alone or with a
frequency exaggerated, may introduce resistance phenomena in the fungus.
Once that occurred the conditions described above can be carried out the first treatment, using only coverage such as shelter. Especially
in the case of heavy rainfall, starting from pre-flowering (late May)
until all'allegagione treatments must be performed with both types of
fungicide every 15 days; further interventions can be carried out by
means of copper-based products that promote the maturation of the wood
and contain the lussureggiamento growing season.
Powdery
mildew or powdery mildew of the vine (Uncinula necator): is a fungus
that affects the leaves, buds, shoots and clusters; favored by high
humidity, optimal temperatures of 25-26 ° C and the absence of wetting. You
notice spots on the leaves grayish-white, while after fruit set on the
berries is the white mycelium of the pathogen that causes necrosis in
the berry, which suberifica and can crack, encouraging other diseases
also, if affects young bunches in phase of pre-flowering, causing the leaking of the flowers and the necrosis of the entire small bunch.
Powdery mildew is a disease typical of vintages hot and dry, also exerts a greater hazard in hilly areas. The
pathogen must be kept under control between the phases of formation of
the clusters (flowering and fruit) until veraison; also in this case is
used to cover fungicides (wettable sulfur) and systemic performing
treatments combining products fungicides and fungicides as it mix well together and both diseases can strike the same period. In areas where powdery mildew is more dangerous than mildew you perform additional actions based on sulfur powder.
Botrytis
or gray mold (Botrytis cinerea): fungus that settles mainly on grapes
from veraison to full maturity; favored by temperatures of around 15-25 °
C and high humidity. The
pathogen penetrates in the vicinity of lesions on the berries,
extending over the entire cluster and manifesting as a gray mold. The grapes are rotting and the product has poor quality, resulting in wines unstable. To
counter the pathogen is important to control other pests of the vine
(powdery mildew, downy mildew and moths) that can cause injury
(excellent entry route for botrytis). Another
mode consists in the use of fungicides botryticides specific, the first
and the second all'invaiatura 20 days before the collection, in order
to reach this stage with grapes healthy.
Esca
or apoplexy: disease caused by a number of fungi that are established
on the wood; favored by the presence of injuries and infected tissues,
from which infects healthy ones. On
the leaves, between the ribs, there is a marked chlorosis yellowish at
the center of the necrotic spots are reddish, while attacks on branches
and wood result in a disruption of woody tissues that necrotize becoming
brown, then take a light color and a spongy texture and friable (decayed tissue). The plant may die a few years after the settlement of these pathogens. This
disease should be evaluated based on preventive measures such as use of
healthy plant material and controlled removal of affected plants,
identification of plants with the first symptoms by avoiding the use of
the same tools of winter pruning cuts, cuts recovery raising the woody part healthy and eliminating the infected.
Escoriosi
(Phomopsis viticola): is a fungus that affects mainly shoots and
branches causing necrotic lesions or abrasions, favored by very wet and
rainy springs. The fruiting canes are woven weaker, lower vigor and a stunted vegetation, this translates into a drop in production. It is important to eliminate the branches affected by pruning, following the budding resort to fungicides against downy mildew.
Bacterial
tumor of the collar and of the roots (Agrobacterium tumefaciens): is a
bacterium that, thanks to the presence of lesions, settles at the level
of the collar but especially the roots, causing tumors (plant cells,
stimulated by the pathogen, multiply so disorganized and abnormal, increasing in volume) that flow, aggregate and mean the death of the infected tissues. The roots affected have a lower absorption capacity, also are altered conductive tissues in the neck and stem. To
minimize the presence of bacteria employ healthy plant material, to
avoid injury to the roots with the means of processing and possibly
resorting to immersion of roots and collar of the plants prior to
planting, in a suspension of living cells of Agrobacterium radiobacter (strain K84), considered an excellent inhibitor of this pathogen.
Flavescence
golden: it is a virus transmitted by an insect (Scaphoideus titanus),
may cause: a sudden stop of the vegetative, curvature of the shoots, no
lignification and chewy texture of the branches, rolling the leaves with
yellowish discoloration of white grapes and impacts red-violet over black grapes, failure to enlargement of the bunch with drying of the grapes. The
symptoms just mentioned can be disrupted, with consequent resumption of
growth, in cases where the pathogen is in a latent state or which has
been transformed into a strain less virulent. The
goal is to control the vector, speaking in mid-June against juveniles;
infected plants should be removed and also a good prevention is the use
of resistant varieties.
Wood
hedgehog: is a virus transmitted by nematodes, appears especially on
vines grafted on rootstocks sensitive is manifested by a considerable
swelling at the graft, with subsequent tissue alterations conductors. In
this case of good agricultural practices include avoiding the immediate
replanting, or to use rootstocks resistant to nematodes.
Vine moth (European grapevine moth) is an insect that affects the inflorescence (1st generation) and clusters (2nd generation). The
larvae of the 2nd generation burrow inside the berries that turn brown
and wither, in the central and southern regions makes a 3rd generation
in late summer, when the grapes are ripening, and it is very dangerous
because the wounds encourage gray mold caused attacks.
Moth
vine (Eupoecilia ambiguella): Unlike the moth its spread is limited to
the areas of northern Italy, in which performs two generations, the 2nd
generation can last until October.
The
fight against moths is based on minimal use of insecticide treatments,
because they tend to favor the infestation of spider mites, eliminating
the natural enemies. For
monitoring using two pheromone traps per hectare (early April),
checking them 2-3 times a week if you are capturing more than 15-20
adult moth and over 10 adult moth is done. The sampling should be carried out in 100 clusters, if the infestation of larvae of 2nd generation exceeds 5% must intervene. Prior to the entry of larvae in the berries you may distribute biological formulated based on Bacillus thuringiensis subsp. Kurstaki, in addition there are also several natural enemies to be favored.