Oidium, known also by the name of “Mal bianco” (“White rust”), is one of the most serious fungus pathologies of the grapevine and may impact in a disastrous way its production by reducing both by quantity and quality the grapes produced. Oidium was reported for the first time in 1847 in Paris and spread rapidly throughout Europe, reaching Italy in 1851. It grows mainly where the climactic conditions are humid, averagely warm and where the circulation of air is scarce. It attacks the leaves, the inflorescence, the shoots which are still green and the grapes, covering them with a white-grey fine dust which smells like mushrooms. It is fought by spraying with sulphur or by using an antagonist of the oidium, the Ampelomyces quisqualis.
Phylloxera in the grapevines is an insect (aphids or plant lice) which attacks the roots of the European species of grapevines (Vitis vinifera) and the leaves of the American grapevines. This harmful phytophagous, originating from North America, appeared in Europe during the second half of the 1800s, provoking in a very short time serious damage to the vinyards throughout Europe. Today, Phylloxera can be found in almost all the areas where grapes are grown throughout the world (with the exception of small islands where the insect hasn’t arrived and in few areas where the soil is sandy or gravelly where the aphids can’t survive). The only way to fight it is by grafting the European vines with roots (rootstocks) of
American vines: since these have lived with this insect for centuries, the American vines have developed a resistance which prevents the insects from attacking the roots.
Peronospora is one of the most serious diseases of the grapevine and is caused by the fungus Plasmopara viticola which penetrates into the vegetal cells and sucks away the nutrition from the plant. The symptomology becomes evident where there is humidity. Typical “oil stains” form on the top side of the leaf while on the underside of the leaf a whitish “mould” forms from the reproductive organs and
these have a typically fishy smell. When the grape bunch is attacked, the ends deform, curving inward first like a hook and taking on a brownish colour, and then drying up. Rame, in its different formulas, is the best anti-peronosporic product because it is extremely effective and is used in conventional winegrowing as well as bio-winegrowing
Esca disease is a fungus disease, known to man from the earliest of times, originatin in the colonization of different species of fungi, whose main agents which cause this disease are: Phaeomoniella chlamidospora, Phaeoacremonium spp., Botryosphaeria spp., Fomitiporia mediterranea. Typical symptoms are reddening alternated by necrotic areas of the leaf lamina and the dehydration of the berries and the grape bunch drying up. In more serious cases, it causes the death of the entire plant. Since it is a disease caused by fungi which live on wood, contamination happens through large cuts from pruning, by equipment, by late suckering. The main means of diffusion of this disease is wind and rainwater.
Golden Flavescence is a serious epidemic disease caused by microorganisms which are similar to bacteria, called phytoplasms. In the Veneto Region, this disease appeared in the 80s, initially on Chardonnay, but then spread quickly to Glera. Its name is attributed to the yellowy colour that the leaves take on when they are attacked. Golden Flavescence is transmitted by a carrier insect called the Scaphoideus Titanus leafhopper which lives on the vines and transmits the disease very efficiently. The fight consists in chemically intervening on the carrier insect and argonomically by drastically pruning or eradicating the plants that have been infested. The Glera vine is rather good at reacting against this disease and the infected adult plants may regenerate within 2-3 years thanks to careful pruning and good phytosanitary action.