1902 Encyclopedia > Vine

Vine




VINE. Of the grape vines (Vitis) V. vim/era is the species best known and longest cultivated ; but out of ten species that grow wild in the United States four (V. rotundifolia, V. Labrusca, V. aestivalis, and V. cordifolia), according to Engelmann, are cultivated and have given origin to numerous derivatives used for wine-making pur-poses. Some of the American varieties have been intro-duced into France and other countries infested with Phyllo-xera, to serve as stocks on which to graft the better kinds of European vines, because their roots, though per-haps equally subject to the attacks of the insects, do not suffer so much injury from them as the European species. American vines should not, however, be introduced for grafting or other purposes into a vine-growing country hitherto free from Phylloxera, but only into those in which the insect has already spread.
Although the genus Vitis comprises, according to Ben-tham and Hooker, more than two hundred species, mostly natives of tropical or subtropical regions, yet less than
half-a-dozen species have any economic value, while the great interest centres in four or five only. Vines have woody climb-' ing stems, with alternate, palm-ately-lobed, or in some

Vine, (i.) Flower after fall of petals ; magnified, (ii.) Fruit ; reduced, (iii.) Foliage, tendril, and inflorescence ; reduced.

cases (Ampélopsis, Cissus) compound (digitate), leaves, provided at the base with small stipules. Opposite some of these leaves springs a tendril, the nature of which is obvi-ous from the numerous transitional states it offers between the ordinary form of tendril and the inflorescence. The flowers are small, green, and fragrant, and are arranged in dense clusters. Each has a small calyx in the form of a shallow rim, sometimes f our-lobed or five-lobed, or toothed. Within this is an equal number of petals, which in the true vines cohere by their tips and form a cap or hood, which is pushed off when the stamens are ripe. In other species (and as a malformation in the vine itself) the petals are free and spreading. Four or five free stamens, placed opposite the petals, spring from a fleshy ring or disk sur-rounding the ovary, each bearing a two-celled anther. The ovary is surmounted by a sessile stigma and is more or less completely two-celled, with two erect ovules in each cell. This ripens into the berry and seed. Blanchon, in his monograph of the Ampelidem (1887), divides the genus Vitis into numerous genera of equal rank. He retains, however, the grape vines under their original name. The cultivated vine has usually hermaphrodite flowers ; but, as it occurs in a wild state, or as an escape from cultivation, the flowers manifest a tendency towards unisexuality : that is, one plant bears flowers with stamens only, or only the rudiments of the pistil, while on another plant the flowers are bisexual. Exclusive!}7 female flowers without stamens do not appear to have been observed. Seedling plants from the cultivated vines often produce unisexual flowers, thus reverting to the feral type. Perhaps the ex-planation of the fact that some of the cultivated varieties are, as gardeners say, "bad setters,"—i.e., do not ripen their fruit owing to imperfect fertilization,—is to be sought in this natural tendency to dicecism.
The conformation of the vine stem has elicited a vast amount of explanatory comment. The most generally accepted explanation is the "sympodial" one. According to this, the shoot of the vine is a " sympode," consisting of a number of "podia" placed one over the other in longitudinal series. Each podium consists of a portion of the stem bearing one or more leaves, each with an axil-lary bud or buds, and terminating in a tendril or an inflor-escence. In V. Labrusca there is a tendril opposite to each leaf, so that the podium bears only a single leaf. In other species there is a definite arrangement of the leaves, some with and others without tendrils opposite to them, the numerical order remaining constant or nearly so. These arrangements have doubtless some reference to climatic phenomena, continuity of growth being arrested by cold and promoted by warmth. In any case it is obvious that these facts might be turned to practical ends in cultiva-tion. A vine, for instance, that produces bunches of grapes at each joint is preferable to one in which there are several barren joints, as a larger quantity can be grown within a smaller area. The practice of pruning or " stop-ping," as explained under HORTICULTURE (vol. xii. p. 277), is consciously or unconsciously regulated by the mode of growth. The tendril or inflorescence, according to the views above explained, though in reality terminal, is bent to one side ; hence it appears to be lateral and opposite to the leaf. While the tendril is thus diverted from its orginal direct course, the axillary bud of the leaf opposite the tendril begins a new podium, by lengthening into a shoot which assumes the direction the tendril had prior to its deflexion. This new podium, now in a direct line with its predecessor, produces leaves and ends in its turn in a tendril or inflorescence. A third podium succeeds the second, and so on. Other authorities explain the forma-tion of the tendril and its anomalous position opposite to a leaf by supposing that the end of the stem bifurcates during growth, one division forming the shoot, the other the tendril or inflorescence. It is not possible within the limits at our command to specify the facts and arguments by which these theories are respectively supported. Prac-tically the tendrils assist the plant in its native state to scramble over rocks or trees. As in the case of similar formations generally, they are endowed with a sensitive-ness to touch which enables them to grasp and coil them-selves round any suitable object which comes in their way, and thus to support the plant. The tendrils of the Virginian creeper ( Vitis or Ampélopsis hederacea ; the Parthenocissus quinquefolia of Planchon) are branched, each branch terminating in a little sucker-like expansion by means of which it adheres firmly to walls or rocks. This is especially noticeable in the Japanese species now so commonly grown against walls under the name of Ampélopsis Veitchii (the Parthenocissus tricuspidata of Planchon). The extremities of these tendrils turn away from the light, and by this means they are enabled to enter crevices, inside which they expand and fix themselves, just as the lewis or key, used by stone-masons, is fixed into blocks of stone. The anomalous position of the stamens in front of the petals is explained by the abortion or non-development of an outer row of stamens, indica-tions of which are sometimes seen on the hypogynous disk

encircling the ovary. The seeds or grape stones are some-what club-shaped, with a narrow neck-like portion beneath, which expands into a rounded and thickened portion above. On the inner or central side of the seed is a ridge bounded on either side by a shallow groove. This ridge indicates the point of union of the " raphe " or seed-stalk with the seed ; it serves to distinguish the varieties of V. vinifera from those of other species. In the true vines the neck of the seed is much longer than in the American vines, and the ridge or "chalaza" occupies the upper half of the seed, not the middle portion, as in the American kinds. In endeavouring to trace the filiation and affinities of the vine, the characters afforded by the seed are spe-cially valuable, because they have not been wittingly inter-fered with by human agency. Characters derived from the size, colour, or flavour of the berry are of less value for historical or genealogical purposes than those which are the outcome of purely natural conditions.
The native country of the European vine is considered to be the region south of the Caspian. From this pre-sumed centre it has spread eastwards into Central Asia and westwards to both sides of the Mediterranean, Central Europe, and as far north as Belgium (Planchón). Begel has propounded the notion that the cultivated vine origin-ated as a hybrid between V. vulpina and V. Labrusca, both North-American species; but he offers little evidence in support of his opinion, which has not received the assent of botanists generally. It is interesting to note that grape stones have been found with mummies in Egyptian tombs of not later age than 3000 years. The seeds, according to Engelmann, have the characteristics of those of V. vinifera, but show some very slight variations from the type of seed now prevalent. Among the Greeks in the time of Homer wine was in general use. The cul-tivation of the vine must also have been introduced into Italy at a very early period. In Virgil's time the varieties in cultivation seem to have been exceedingly numerous; and the varied methods of training and culture now in use in Italy are in many cases identical with those described by Columella and other Boman writers (comp. HORTICULTURE, vol. xii. pp. 223, 277). Grape stones have been found among the remains of Swiss and Italian lake dwellings of the Bronze period, and others in tufaceous volcanic deposits near Montpellier, not long before the historic era.
The vine requires a high summer temperature and a prolonged period in which to ripen its fruit. Where these are forthcoming, it can be profitably cultivated, even though the winter temperature be very low. Tchihatchef mentions that at Erivan in Bussian Armenia the mean winter temperature is 7°"1 C. and falls in January to — 30° C, and at Bokhara the mean temperature of January is 4° C. and the minimum - 22° O, and yet at both places the vine is grown with success. In the Alps it is profit-ably cultivated up to an altitude of 1870 feet, and in the north of Piedmont as high as 3180 feet. At the present time the limit of profitable cultivation in Europe passes from Brittany, lat. 47° 30', to beyond the Rhine by Liége and through Thuringia to Silesia in lat. 51° 55' (Grise-bach). In former centuries vines were cultivated to the north of this region, as, for instance, in Holland, in Bel-gium largely, and in England, where they might still be grown. Indeed experiments have lately been made in this direction near Cardiff in South Wales. The yield is satisfactory and the wine made, the variety known as Gamay noir, is described as being like still champagne. In the Middle Ages, owing to various causes, the better wines of France and Germany could not be obtained in England except at prohibitive prices; but, when this state of things ceased and foreign wine could be imported, the English consumers would no longer tolerate the in-ferior productions of their own vineyards. It is also prob-able that the English mixed sugar or honey with the wine and thus supplied artificially that sweetness which the English sun denied. It is a curious fact that at the present day much or even most of the wine of finest quality is made at or near to the northern limits of possible cultivation with profit. This circumstance is probably explained by the greater care and attention bestowed both on the cultivation of the vine and on the manufacture of the wine in northern countries than in those where the climate is more propitious. The relative inferiority of the wines made at the Cape of Good Hope and in Australia is partly due to variations of climate, the vine not yet having adapted itself to the new conditions, and partly to the deficient skill of the manufacturers. That such inferi-ority may be expected to disappear is suggested by the success of vine-culture in Madeira and the Canary Islands.
The development of other species of Vitis, such as the curious succulent species of the Soudan and other parts of equatorial Africa, or the numerous kinds in India and Cochin China, is of course possible under suitable con-ditions ; but it is obvious that an extremely long period must elapse before they can successfully compete with the product of many centuries.
For currants and raisins, both produced by varieties of the grape-vine, see the respective articles.
Apart from their economic value, vines are often culti-
vated for purely ornamental purposes, owing to the elegance
of their foliage, the rich coloration they assume, the shade
they afford, and their hardihood. (M. T. M.)
DISEASES OF VINES.
The organic diseases which affect the vine may be divided into two categories, those caused by insects and those caused by para-sitic fungi.
Diseases Caused by Insects.—Kaltenbach in 1874 enumerated Insect thirty-two species of insects which injure the vine ; and since then enemies, others have been added to the list. "We here deal only with the most important. Amongst those which attack the leaves and young buds a small beetle, Anomala vitis, one of the Scarabmidae, does great harm in some parts of southern Europe by devouring the soft tissue of the leaves. A genus of weevils, Oliorhynchus, contains several species which are injurious to the vine, chiefly by the adult beetle devouring the buds. 0. raucus, hirticornis, picipes, nigritus, ligustici, and sulcatum are all reported from various places as doing much damage ; the larva of the last-mentioned species attacks the roots of the vine, causing the shoots to be small and ultimately bringing about the death of the plant. Fortunately the members of this genus have no wings, so that the damage they cause is to a great extent localized. The same kind of injury is caused by a small Chrysomeleous beetle, Eumolpus vitis. The larvae of several Lepidoptera attack the vine in the same way, destroying the young buds. Amongst these Nsenia typica, Agrotis tritici, and A. pronuba may be mentioned. The larva of Tortrix pilleriana in the early spring weaves the young vine leaves to-gether, and, enclosed in this nest, devours the soft tissue at leisure The imago emerges from the chrysalis in July and shortly after lays its eggs upon tine upper surface of the vine leaf. After a few weeks the caterpillars emerge and continue their work of destruction. Lethrus cephalotes, one of the Searabmidae, is very injurious in vineyards which have a dry sandy soil. The beetles live in pairs in holes in the ground ; during the summer the beetle bites off the small young shoots and drags them away to its hole, where it is believed they serve as food for the larvae. In this way very serious damage is caused to the vine plants. Bhynchites betuleti, a weevil, also does much damage to the young shoots and leaves. The grapes are attacked by the caterpillar of a moth, Conchylis ambiguella, which lays its egg in the young fruit; and in a similar way the larva of Graptolitha (Conchylis) botrana attacks the flowers and fruit. The larva of the cockchafer, Mclolontha vulgaris, also does much damage by biting through and devouring the roots. Coccus vitis is a small scale insect of reddish brown colour, with irregular black spots in the female, which lives in the bark of old or neglected vines and weakens the tree.
By far the most destructive of all insect pests which attack the Phyllo-cultivated vine is Phylloxera vastatrix. This much-dreaded insect xera. belongs to the family Aphidx or plant lice of the order Hemiptera. The genus contains several species which live upon oak trees. Their proper home is in North America ; but they have been found


in English vineries since 1863. The symptoms of the disease first appeared in France about the same time, in the neighbourhood of Tarascon. From the department of Gard the infection spread south to the sea, and east, west, and north, till the south-eastern corner of France was thoroughly infected. Another centre of infection arose a few years later near Bordeaux in Gironde, whence the disease spread till the whole of the southern half of France was more or less severely attacked. The parasite was first discovered in France in the year 1868. The Phylloxera has spread to Corsica ; it has appeared here and there amongst the vineyards of the Khine and Switzerland ; it is found in Spain and Portugal, Austria, Hungary, Italy, and Greece ; and in 1885 its presence was discovered in Australia (Victoria), at the Cape of Good Hope, and in Algeria. Hence it is no exaggeration to say that with very few exceptions its distribution is co-extensive with that of the cultivated grape-vine.
The symptoms of the disease, by means of which an infected spot may be readily recognized, are these. The vines are stunted and bear few leaves, and those small ones. When the disease reaches an advanced stage, the leaves are dis-coloured, yellow or reddish,with their edges turned back, and withered. The grapes are arrested in their growth and their skin is wrinkled. If the roots are examined, numerous fusiform swellings are found upon the smaller rootlets. These are at first yellowish in colour and fleshy ; but as they grow older they become rotten and assume a brown or black colour. If the roots on which these swellings occur be examined with a lens, a number of minute insects of a yellowish brown colour are ob-served ; these are the root-forms (radicola) of Phylloxera (fig. 1); they

FIG. 1.—Root-inhabiting form (radicola) oí Phylloxera, with proboscis inserted
into tissue of* root of vine. FIG. 2.—Phylloxera. Winged female which lives on leaves and buds of vine,
and lays parthogenetically eggs of two kinds, one developing into a wingless
female, the other into a male.
are about '8 mm. long, of an oval outline, and with a swollen body. No distinction between head, thorax, and abdomen can be observed. The head bears small red eyes and a pair of three-jointed antennae, the first two joints being short and thick, the third moro elon-gated, with the end cut off ob-liquely and slightly hollowed out. Underneath, between the legs, J lies the rostrum, which reaches back to the abdomen. The insect
is fixed by this FIG. 3.—a, Male produced from small e¡,_ rostrum, which is female (fig. 2); b large egg; c, small egg.
i. i o .i. 4.1 FIG. 4.—Wingless female produced from large e¡ inserted into the laid by wi =ged temale (^g, 2).
root of the vine
for the purpose of sucking the sap. The abdomen consists of seven segments, and these as well as the anterior segments bear four rows of small tubercles on their dorsal surface. These root-dwelling insects are females, which lay parthenogenetic eggs. The insect is fixed by its proboscis, but moves its abdomen about and lays thirty to forty yellow eggs in small clusters. After the lapse of six, eight, or twelve days, according to the temperature, the larvae hatch out of the eggs. These are light yellow in colour and in appearance resemble their mother, but with relatively larger appendages. They move actively about for a few days and then, having selected a convenient place on the young roots, insert their proboscis and become stationary. They moult five times, becoming with each change of skin darker in colour ; in about three weeks they become adult and capable of laying parthenogenetic eggs. In this way the insect increases with appalling rapidity: it has been calculated that a single mother which dies after laying her eggs in March would have over 25,000,000 descendants by October. If, however, the insect were content with this method of reproduction, the disease could be isolated by surrounding the infected patches with a deep ditch full of some such substance as coal-tar, which would prevent the insects spreading on to the roots of healthy vines. The fertility of the parthenogenetically-produeed insects would also diminish after a certain number of generations had been produced.
As the summer wears on a second form of insect appears amongst the root-dwellers, though hatched from the same eggs as the form described above. These are the nymphs, destined to acquire wings; their body is more slender in outline, and at first they bear well-marked tubercles. After several moults the rudiments of two pairs of wings appear, and then the insect creeps up to the surface of the earth, and on to the vine. Here it undergoes its fifth and last moult, and appears as a winged female, capable of reproducing parthenogenetically. The winged form has a slender body with distinct head (fig. 2). The eyes are well developed, with numerous facets ; the antennae have three joints, the terminal one shaped like that of the root-dwellers. The wings are transparent, with few nervures, and are well adapted for flight. The anterior pair reach far beyond the end of the abdomen; the posterior are narrower and not so long. These winged forms are about 1 mm. long. 'They fly about from July till October, living upon the sap of the vine, which is sucked up by the rostrum from the leaves or buds. They lay their parthenogenetically-produeed eggs in the angles of the veins of the leaves, in the buds, or, if the season is already far advanced, in the bark. In very damp or cold weather the insect, remains in the ground near the surface, and deposits its eggs there. The eggs are very few in number and of two sizes, small and large (fig. 4, b and c). From the larger a female (fig. 3) is hatched in eight or ten days, and simultaneously, for the first time in the life-history of the Phylloxera, a male (fig. 4) appears from the smaller egg. Neither male nor female has wings ; the rostrum is replaced by a. functionless tubercle; and there is no alimentary canal. The female is larger than the male and differs from it and the other forms in the last joint of the antennae. The life of these sexual forms lasts but a few days, and is entirely taken up with reproduc-tion. The female is fertilized by the male and three or four days later lays a single egg—the winter egg—and then dies. This egg is laid in the crevices of the bark of the vine, and as it is protectively coloured it is almost impossible to find it. Here the winter eggs-remain undeveloped during the cold months ; but in the following-spring, as a rule in the month of April, they give birth to a female insect without wings, which resembles the root-dwelling forms, but has pointed antennae. These forms are termed the stock-mothers ; they creep into the buds of the vine, and, as these develop into the young leaves, insert their proboscis into the upper side. By this means a gall is produced on the under side of the leaf. The gall is cup-shaped, and its outer surface is crumpled and covered with small warts and hairs. The opening upon the upper surface of the leaf is protected by similar structures. Within this gall the stock-mother lives and surrounds herself with numerous parthenogenetic-ally-produeed eggs,—sometimes as many as two hundred in a single gall; these eggs give birth after six or eight days to a numerous progeny (gallicola), some of which form new galls and multiply in the leaves, whilst others descend to the roots and become the root-dwelling forms already described. The galls and the gall-producing form are much commoner in America than in the Old World.
Scheme of the Various Forms of Phylloxera vastatrix. A. Root-infesting forms, 9
Winged forms, 9
Male.
sic.
Root-infesting forms, 2d generation, 9 Root-infesting forms, 3d generation, 9
The natural enemies of tha Phylloxera are few in number : they include some mites,—Hoplophora arctata, Thyroglyphus phylloxeras, —and the millepede Polyxenus lagurus, which devours the subter-ranean forms. Innumerable artifices have been proposed to com-bat the terrible disease caused by this minute insect, but none of them seem to be completely successful. As a rule the means siua;-
Wingless female.


gested 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. (Hdium. Fungoid Diseases.—The most destructive form of fungoid disease which attacks the vine is caused by a Pyrenomycetous fungus, (Hdium (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 hyphae composing the mycelium are provided with haustoria, which project into the cells of the affected part. Some of the hyphae 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, Cicinnobolns Cesatii, De By, which lives parasitically within the hyphae 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, spora is Peronospora viticola. The mycelium spreads through the green mticolo,. 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 off. 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 "charbon," "pech," or "brenner." This nose. disease is caused by the parasitism of Sphaeeloma ampelinum, 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 advances, 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 Sphaee-loma grows just beneath the cuticle of the vine, through which it soon bursts, giving rise to a number of minute hyphae, 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 World. 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 Bidwcllii, Sacc. (Phoma uvicola), one of the Pyrenomycetes, and by some authorities it has been considered to be a further stage in the life-history of Sphaeeloma. 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 g' ape. The latter at first retains its plumpness, but on the appearauce 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 hyphae of the mycelium of this fungus are sep-tate, with numerous short branches. The pustules o'.i the surface are due to fructifications, pyenidia, and spermagonia. 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. Labruscee, 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 Pyrenomycetes. To the same class belongs also Oercospora vitis (Cladosporium viticolum), which has club-shaped spores of a green-brown colour. This also attacks the leaves ; but, unless the season is extremely unfavourable, it does little harm.
A very disastrous root-disease of the vine is due to the ravages
of the fungus Dematophora necatrix, 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 Discomycetes. 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.)









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