Page:Encyclopædia Britannica, Ninth Edition, v. 24.djvu/262

Rh 240 V I N V I N gestcd are to render the soil uninhabitable for the root forms by injecting certain chemical poisons. Since the importance of the winter egg in the life-history of the insect was demonstrated by Balbiani, attempts have been made to destroy these eggs by rubbing the branches with a chain-armour glove, or some such contrivance for removing the outer layers of the bark, which should be burnt. Again, certain varieties of American vines, which have the reputa tion of being Phylloxera proof, have been grafted on European stocks; but this has proved to be only a doubtful success as regards the Phylloxera, whilst the wine made from such vines has un doubtedly deteriorated. The treatment which has been most suc cessful is periodically to submerge the vineyard for a period of not less than forty days. Where this plan has been tried, it has been most successful ; unfortunately the majority of vineyards are planted on hill-sides and other places where this method of treat ment is impracticable. The root-dwelling forms do not thrive in a sandy soil ; hence vines grown in a district where such soil is found usually escape the disease. Oidium. Fungoid Diseases. The most destructive form of fungoid disease which attacks the vine is caused by a Pyrenomycetous fungus, Oidium (Erysiphe) Tuckeri. The disease was first noticed in England in 1845 ; in 1848 it appeared at Versailles ; by 1851 it had spread through all the wine-producing countries of Europe, being especially virulent in the lands bordering on the Mediter ranean ; and in the following year it made its appearance in Madeira. There is little doubt that, like the Phylloxera, the Oidium is in its origin American. The disease is characterized by the appearance of a white mycelium on the young leaves ; this spreads quickly and attacks the older leaves and branches, and ultimately reaches the grapes. At first these are marked only by small brown spots ; but the spots spread and fuse together, the skin of the grape is destroyed, and the flesh decays, the seed only remaining apparently untouched. The disease spreads by the mycelium growing over the epidermis of the plant. The hyphse composing the mycelium are provided with haustoria, which project into the cells of the affected part. Some of the hyphpe which project from the leaf bear conidia, which are constricted off one at a time, and it is by their means that the fungus spreads. The perithecia have not yet been discovered in Europe. But it is not impossible that this stage of the life-history of Oidium exists in the United States in the form of Uncinula spiralis, which causes a widely spread disease amongst the American vines. The Oidium is in its turn attacked by a fungus of the same tribe, Cicinnobolus Cesatii, De By, which lives parasitically within the hyphse of its host, and at times even succeeds in destroying it. The means which have proved most efficacious, both as a remedy and a preventative of this disease, is to scatter flower of sulphur over the vines, before the morning dew has evaporated. Another method is to boil one part of lime with three parts of sulphur, and to sprinkle the mixture over the affected plants. Perono- Another fungus which attacks vines, especially those of America, apora is Peronospora viticola. The mycelium spreads through the green viticola. parts of the plant, attacking the leaves, twigs, and unripe grapes. On the upper side of the leaf, where it is first visible, it forms pale green irregular spots, which become darker in colour. On the under side of the leaf these patches are white and are composed of the spore-bearing hyphae. The leaf ultimately becomes dried up and brittle. The grapes which are attacked cease to grow, turn brown or white, and ultimately dry up and fall oif. This disease has been successfully treated with a spray of copper sulphate and lime, or sulphate of iron ; solutions of these salts prevent the conidia from germinating. An- Anthracnose is the name usually given to a disease which was thrac- formerly known as &quot;charbon,&quot; &quot;pech,&quot; or &quot;brenner. &quot; This nose. disease is caused by the parasitism of Sphaceloma ampclinum, one of the Pyrenomycetous fungi. The fungus assails all the green parts of the vine, and injures the leaves and young shoots as much as it does the grape itself. The first sign of its presence is the ap pearance of a minute spot, which is greyish in the centre, with a brown border. This spot increases in size ; in the stalks it assumes an oval shape, with its long axis parallel to the stalk, whilst in the leaves and grapes it is more or less circular in outline. The centre of the spots on the grapes becomes darker as the disease ad vances, and a red line appears dividing the dark brown border into an outer and an inner rim and giving a very characteristic appear ance to the diseased plant. The berries do not shrivel up as those do that are affected by the black rot. The mycelium of Sphace- lom t grows just beneath the cuticle of the vine, through which it soon bursts, giving rise to a number of minute hyphte, which bear conidia. These are minute, oval, colourless spores, which serve to spread the disease over the vineyard and from place to place. The complete life-history of this form is at present unknown ; and in formation as to where the fungus passes the winter, and in what form, would probably afford some useful indications as to the method that should be adopted to combat the disease. Anthracnose has been known in Europe for many years, but has only been ob served in America since 1881, whither it was probably imported from the Old &quot;NVorld. As a preventative to its attacks a solution (50 per cent.) of iron sulphate has been found very useful, as well as care in planting on well-drained soil that does not lie too low, the disease seldom appearing in dry, well-exposed vineyards. The black rot, like the Oidium and P. viticola, is American in its Black origin. It has been known and observed there since 1848, but ap- rot. peared for the first time in France in 1885. The disease is caused by a fungus, Physalospora BidweUii, Sacc. (Phoma uvicola), one of the Pyrenomycctes, and by some authorities it has been considered to be a further stage in the life-history of Sphaceloma. The fungus confines its attacks to the grapes, the leaves and stems being rarely if ever affected. The grapes are not assailed until nearly full-grown, when a brownish spot appears, which spreads over the whole grape. The latter at first retains its plumpness, but on the appearance of little black pustules, which first occur on the part first affected, the grape begins to shrivel. This continues until the grape is reduced to a black hard mass, with the folds of skin pressed closely against the seed. The disease does not spread from grape to grape, so that as a rule only a certain number of grapes in a bunch are destroyed. The hyphse of the mycelium of this fungus are sep tate, with numerous short branches. The pustules on the surface are due to fructifications, pycnidia, and spennagonia. The presence of conidia has also been recently demonstrated. The fungus passes the winter in the withered grapes which fall to the ground ; hence every care should be taken to collect these and burn them. The use of the solutions mentioned above may also be recommended as a preventative. Among the other fungi which infest the vine may be mentioned Other Phyllosticta viticola and Ph. Labruscaz, which, when the attack is fungi. severe, cause the destruction of the leaves, the only part they assail. These, like the foregoing, are members of the Pyrcnomycetcs. To the same class belongs also Cercospora vitis (Cladosporium vMcolum), which has club-shaped spores of a green-brown colour. This also attacks the leaves ; but, unless the season is extremely unfavour able, it does little harm. A very disastrous root-disease of the vine is due to the ravages of the fungus Dcmatophora nccatrix, which forms subterranean strings of mycelium so-called rhizomorphs the fructification of which is as yet not known ; it forms conidia and sclerotia, however, and presents certain analogies to the Discomycctcs. The diseased roots have been confounded with those attacked by Phylloxera. The only mode of combating the malady seems to be to uproot the plants and burn them. Isolation of the diseased areas by means of trenches has also been practised. This fungus has extended its ravages considerably in southern France and Switzerland within the last ten years. (A. E. S. ) VINEA. See VIGNA. VINEGAR is a dilute form of acetic acid, having a flavour that varies according to the source from which it is obtained. Vinegar has been known from the earliest historical period, and its power of acting on and dissolving- mineral substances rendered it an important agent in the hands of the alchemists. They were, however, unac quainted with pure acetic acid ; the most concentrated solution they possessed, called spiritus veneris, was obtained by distillation from cupric acetate (verdigris). The nature of acetous fermentation, and the rationale of the processes by which vinegar is prepared, are explained under FEU- MENTATION (vol. ix. p. 98) ; and the acetic acid obtained by the destructive distillation of wood is dealt with under TAR (vol. xxiii. p. 57). Here we have to do only with the various kinds of vinegar used for table, medicinal, and other household purposes. Malt, wine, and beetroot vinegars are made by the slow process, whilst for the quick method dilute brandy or other spirit is most largely employed. Malt vinegar is the preparation commonly manufactured in the United Kingdom, the high alcoholic duties there excluding the use of spirits in the industry. A fermented wort is prepared, as in brewing, which is run into casks laid on their side, bung-hole upwards, till they are three-fourths filled. These casks have a hole bored in each end near the top, and between the three holes a con stant circulation of air is secured over the surface of the liquid. The casks are disposed in low-roofed vaults, artificially heated, in which free circulation of air is kept up ; but sometimes the process is carried on in the open air in what is termed a vinegar field. According to the temperature (which should he about 70 Fahr.) and other conditions, the acetification of the wort may occupy from weeks to months. From the casks the vinegar is transferred to large tuns provided with false bottoms, over which a thick layer of stalks and skins of grapes and raisins, &c., termed rapes, is strewn. Through this the vinegar is filtered from one tun into another,