THE GRAPE DISEASE IN EUROPE;

ITS
ORIGIN, HISTORY, PHENOMENA AND CURE
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BY HENRI ERNI, M. D., DEPARTMENT OF AGRICULTURE.
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The grape disease being with us a growing evil, threatening the total destruction of some of our native American varieties of vines, like the Catawba, I have deemed it important to give a brief history of the destructive malady which has prevailed of late in European vineyards, hoping it may to some extent aid in understanding the character of diseases of the grape which are beginning to prevail in this country.

The literature upon the subject of grape disease is meagre. The books consulted in writing the following article were, principally: Lowis Leclerc, Les vignes maladé, report to the minister of the interior, Paris, 1853. The plates annexed were copied from this report. Dr. H. Schwartz, Chemie und Industrie unserer Zeit; Breslau, 1862. Dr. W. Hamm’s Weinbuch, Leipzig, 1865. Marés diseases of the wine stock, in “ Memoires de la Société Impériale et Centrale d’Agriculture ” An extract of the above, in Journal de Pharmacie et de Chemie, Mai, 1857, p. 355; also, in Dingler’s Polytechnisches Journal, Bd. cl., 1858, pp: 148-153. J.T. A. Barral: Cure of the vine disease, with instructions how to apply sulphur, and figures of the apparatus, from “Extrait du Journal d’Agriculture Pratique,” No. du 20 Juin, 1857. Paris, Librarie Agricole de la Maison Rustique rue Jacob, 26.

The year 1845 will ever be a painfully memorable one, by giving birth to two new diseases which threatened the entire destruction of the potato and wine crop, and which caused suffering, devastation, and pecuniary ruin to an incredible extent on the continent of Europe.

It would require a great deal of space even to allude to the different theories and opinions advanced as to the cause of these diseases. Suffice: it to state, that time has proved the majority of them to be fallacious. All such as imputed to peculiar electric conditions, a wet season, or other meteorological influences, and in seasons remarkable for dryness, are manifestly refuted, whilst the gradual accumulation of scientific facts has established, almost beyond dispute, that the potato and wine diseases are not only accompanied by, but result from, fungus or mouldy growths. Limiting our remarks here more particularly to the wine disease, we begin with its

HISTORY.

In the spring of 1845 this disease was observed for the first time in Kent England, on vines raised in the hothouse of Mr. Tucker. The termination of the young shoots assumed, first, a crispy look, began to wither, and then dried up. The unripe grapes were next attacked, becoming covered with a grayish white bloom, destroying the skin of the berries, and causing them to rot and dry up. This fearful disease spread itself speedily over other English grape hothouses; was observed almost simultaneously in like establishments at Paris, and passed thence over France, Italy, Greece, Tyrol and Hungary, affecting somewhat later and more feebly the vineyards on the Rhine. Rev. M. J. Berkeley, of Bristol, an eminent naturalist, who has devoted his life to the study of these minute organisms, was consulted, and diseased grapes submitted to his examination. He at once ascribed the cause of this injury to a new species of the botanical genus Oïdium, a vegetable fungus or parasite which, in honor of the horticulturist at Margate, he termed Oïdium Tuckeri. [The fungus is now known by its sexual stage name, Uncinula necator -ASC]. The genus Oïdium established by Link, belongs to the agamous plants, and is included in the Mucedineous family, (moulds.) It is described as a vegetable parasite preying upon living plants, like lice and ofher animal parasites upon animal species. At first this mould forms webby creeping filaments known in botanical language as Mycelium, these root-like fibres then branch out, sending up straight or decumbent articulated stems, These bead-like joints fill up successively with seeds or spores which are discharged at the proper time to multiply the species.

EFFECTS OF THE PARASITE UPON THE VINES.

The first effect is generally perceived upon the leaves, which, at their vernal growth in vineyards, turn whitish, owing to the development of mycelium, (see Plate I, Fig. 4a,) creeping first over the superior leaf-surface, constituting a felt- like mass, visible plainly under the microscope alone, then invading the whole leaf with rapidity. Sometimes the diseased leaves remain green and smooth, but appear spotted. The spots differ much in appearance, and may be dirty brown and scarcely circumscribed or confluent; sometimes they are black, covering here and there the natural white down of the lower surface of the leaves, according to the variety of the vine. At other times the leaves crisp and curl up under the effect of the parasite, then fade and dry up, or turn black from the centre to the circumference, and, lastly, drop off, from the latter part of July to the beginning of August.

At this stage the vine is in a state of consumption—for the leaves are to plants what the lungs are to animals—and the functions of life are being suspended at the most important period of growth. The mycelium developing upon leaves produces relatively but few branches with seed capsules (spores,) whereas, when growing upon the berries of the grape, these are very numerous. When the shoots are attacked by the disease they are covered with spots of a variable diameter, or with large, irregular, often confluent blotches of a reddish- brown or even black color. (See Plate IV, Figs. 1 and 2.) Generally the spots preserve their primitive color, even after the August sap.

In the most affected vineyards the shoots look as if burned in different places, or as if a red-hot iron had been applied to their herbaceous surface. In several instances the same effect took place on the petioles (stems) of the leaves, and on the peduncles (stems) of the bunches of grapes. At times the shoots may be observed to secrete a clammy inodorous fluid all over their surface. The living parasite has also the power to penetrate into the young wood to the medullary canal, when the summit of the woody texture turns black and dry, and withers from the top down to half its length.

The symptoms presented by the affected grape are more variable. During the first invasion of the oïdium, sometimes before, sometimes after its appearance on the leaves or shoots, a single whitish spot may be seen on a single berry, enlarging itself by radiating in irregular directions. The mycelium, with its fructifying stems, is limited or arrested, at times, in its growth, from some unknown cause; whilst, at others, it. is seen spreading. with great rapidity, covering the entire surface of the berries. If in a bunch there is but one abortive berry, it will bear marks of the disease. The creeping branches of the mycelium are fixed upon the skin of the berry by rootlets which do not penetrate into the juicy pulp. The mycelinm sends up vertical fructiferous branches nearly of the same height, and densely pressed against each. other, velvet-like. These branches are composed of, or subdivided into, transverse cells, (see Plate I, Figs. 1 and 6.) The top cell increases in volume, becomes ellipsoidal, and detaches itself at maturity, or is carried off by the slightest motion of the air, If the conditions (i.e., the temperature and dampness of the atmosphere) are favorable, a second and third cell will follow the same course, (see Plate I, Fig. 2.) These cells, called spores by botanists, correspond to the germs, buds or seeds of the higher orders of plants. The more or less elongated spores of the oïdium mould form capsules, consisting of two transparent integuments or skins, The spores are almost devoid of weight, and so small that their length only amounts to the 1/300 or 1/500 of a millimetre, or [0.0003] to [0.0007] of an inch, English measure. As soon as the deposited spore is favored by circumstances (i.e., a moist atmosphere and a temperature not less than 15° C. or 59° F.) it germinates. A sort of irregular bud (Plate III, Fig. 2, c) bursts forth at one of the ends or poles of the ellipsoid, elongating itself into creeping, webby fibres, which, at length, developing themselves into a net work of branches, form the mycelium. But the oïdium has yet another way of propagation, or revivifying as it were. If the mycelium is reduced to dry, inert, and almost imperceptible fragments, it constitutes, when placed under proper conditions of warmth and moisture, a true cutting, which soon sends forth two or three creeping rootlets, (see Plate III, Fig. 2, d.) These will produce vertical fruit branches, discharging successively the ripe spores, as has been already described.

The first effect observed of the mycelium, when adhering to the surface of the berries, consists in producing elevated, brown, (rarely red or black) points, unless they be certain varieties of grapes attacked toward maturity. Louis Leclere, in his report. to. Monsieur le Ministre Persigny, remarks: “Certain learned physiologists, for whom I have perfect deference, entertain the opinion that these elevated points on the berries appear before the formation of the mycelium. Constant observations, extended for over three months, have failed to reveal to me a single example of such a phenomenon.” Suppose this to be so, are these slight elevations the result of a developing internal sporule, or of the removal of the mycelium? Such apparently trifling facts are of great importance. The appearance of these elevated points before the oïdium proves that it is a pre-existing disease—a kind of eruption. These excrescences or round swellings (Plate III, Fig. 1, a) seem not to penetrate the pellicle, and consequently do not extend into the cellular tissue constituting the pulp of the berries. The excrescences, at first very indistinct, proceed, nevertheless, in irregular lines} according to the direction taken by the sterile base network of the mycelium, The elevated points are readily seen: by the naked eye, by wiping off the oïdium with the finger, or when the latter is removed by some unknown cause, (Plate IV, Fig. 5.) These points are indelibly traced, whether they cover the whole berry, or are distributed in isolated patches; and it is always upon one of these punctuated lines, and longitudinally, that the pellicle of the berries opens, The berries themselves afterwards burst, owing to the weakness of the skin, or the great accumulation of the nutritive juice within. (Plate IV, Fig.5.) The cellular tissue forming the pulp is next torn, leaving the seeds naked. The berry dries up or rots, according to the state of the atmosphere and the more or less advanced stage of the fruit. The berry does not always open in straight lines, sometimes not at all. In the latter case, the fissure in the skin sinks in, forming a furrow, at the bottom of which is sometimes found a bluish or greenish blue fungus, which is not the Oïdium Tuckeri.

The berries infected with Oïdium Tuckeri do not necessarily split or burst open. Louis Leclere has witnessed them in five other conditions: 1. Simply withering, with transient softening and final dryness. 2. When the berry is only half developed the growth is arrested. 3. In spite of the enemy the growth continues until one-half to even three-fourths of the normal final volume is reached, when the berries wither and putrefy. 4. The berry down to the pedicle or stem is completely covered by a dense, thick, brownish or reddish layer, composed of the accumulated webby threads of the desiccated mycelium, somewhat of a woody appearance, with none or but few fructifying branches. In this case the coating may be removed by a sharp instrument, and still the pellicle beneath look perfectly green, and the interior of the berry be in good condition. 5. Finally, and most strangely, the berries from their formation are covered one-half, two-thirds, or even wholly, with mycelium and numerous fertile stems; still they grow, soften, attain the normal size, and mature perfectly.

CIRCUMSTANCES FAVORABLE TO THE INVASION OF THE DISEASE.

From England the disease passed, in 1847, over the English Channel, and became visible in hothouses near Paris. Thence it spread over the vineyards in neighboring districts, and travelled with increased violence over the south of France, Italy, and Hungary.

In 1853 spores of the oïdium crossed the Mediterranean to invade Algeria, Syria, Asia Minor, &e., destroying a most important article of commerce and ruining the cultivators. Happily the disease seems to have yielded to science and human labor combined; when the oïdium had been submitted to the scrutiny of science, which investigated, named, and classified it, the question was earnestly asked whether this disease was the effect or cause. It is still disputed. Likewise, whether the vegetable fungus or mould, called yeast, is the primary agent in starting alcoholic fermentation, as in the manufacture of wine or beer from sugary liquids, or whether these vegetable cells, or yeast, are a secondary production, collecting, (owing to the decomposition of organic materials,) as higher order of fungi collect, on dead leaves and decaying substances generally.

To return to the grape disease. Was the oïdium parasite a new plant previously unknown, which installed itself on a higher order of plant, as the grapevine when it is in full vigor and in a normal condition, there to germinate, propagate, and live, by preying upon the tissues and sap of the vine; or was this terrible evil brought about by an artificial, forced culture, causing deep-seated alteration or disease in the vine, the oïdium fungus or mould prospering while disease or decomposition invaded the vine living under entirely unnatural conditions? These two opinions advanced by naturalists do not appear entirely settled. In searching with due care for the circumstances which favor the invasion of the disease, it has been remarked, in many different localities, that it is developed principally in rich, low, and moist soils. These are generally infected first, and favored by a warm and damp atmosphere, the multiplication of the oïdium spores is indeed enormous and may be counted by millions, The wind raises them up in clouds and distributes them everywhere, even over elevated vineyards. This dissemination of seed spores occurs at a period the most dangerous to the vine, the stem and fruit being in a transition state, and very delicate and susceptible.

A few remarks in regard to the tendency of forced or hothouse culture, as well as of the domesticity of animals, may not be out of place. The mass of mankind are apt to find nothing good in nature but what conforms to their interest. Thus we resolutely assume that animals or plants are ameliorated and improved in consequence of an artificial life inflicted upon them, termed culture or domesticity, which must contribute to our wants, tastes, and even fancy. But these animals, whose muscles and fat ingenious man steadily increases at the expense of the bony tissue; these plants, whose fruit by the care of man increases in size, softness, juice, and flavor, are they truly perfected for their good?—these unnatural, perverted beings, so to speak, whose certain organs enlarge themselves enormously, while others growing more and more delicate and impressible, either perish or become abortive, and are exposed to disease which their wild congeners never contract. Plants do not grow spontaneously and multiply themselves in all soils. It is only under favorable circumstances that particular species can flourish. The Vitis vinifera, or European grape, will grow on this continent (so varied in soil, climate, temperature, &c.) in California alone. And I am informed by my distinguished countryman, the California pioneer, General Sutter, that he successfully raised upon his farm a great variety of trees, shrubs, and flowers peculiar to Europe.

The geographical distribution of plants (i.e., the locality of their proper existence) seems to be determined not so much by the variety of soil as by the intensity of the solar forces, light and heat, and the degree of moisture, all of which are imitated in our greenhouses, where we are wont to grow plants of all zones.

An impressive illustration of the almost marvellous results gained by a successful artificial imitation of the conditions required by different species of plants for their maturity may be seen at Zwickau, in Saxony. Upon a spontaneously burning subterranean coal strata an intelligent gardener built extensive greenhouses, in which the air is saturated with moisture, and wherein reigns, in all respects, a truly tropical climate. Here the sugar-cane and coffee plant can reach their full development. It is said that the owner sells his large crop of pineapples, alone, for 3,000 Prussian dollars annually. Cucumbers, beans and melons ripen within this magic circle at all seasons of the year.

When the plant is placed in circumstances not of its own selection, and left to itself, it disappears, and wonderful artificial contrivances only can maintain it. Then it acquires new qualities at the expense of conservative forces, which the genius of cultivation can never supply. The altered plant can no longer surmount the obstacles offered by the immutable physiological laws of geographical limitation, and the slightest occasion may suffice to induce the destruction of this artificial being. Comparisons are generally bad evidence, but certain connexions presenting themselves may, nevertheless, throw some light on a questionable matter. Count de Gasparin states that the silkworm is now only found in the protecting hands of man, who has altered, if he has improved it. The fact is, says Boissier de Sauvages, the domesticated silkworm has become so stupid that, when placed upon a mulberry tree, it will often gnaw off the stem of the leaf upon which it crawls, and then fall from the tree, up which it is never able to climb. A common caterpillar will never act in thissilly way, and if the wind should blow it down to the ground it climbs up rapidly again to its selected home. The silkworm, as modified by art, will reach its fifth period of transmutation, be lively, healthy, and so great a glutton, that, relatively to its bulk and weight, it devours as much food as thirty-six horses, when, alas! our fine silkworm quivers, twists itself in painful convulsions and dies, What is the cause of this sudden disease? It is occasioned by an agamous parasitical plant—a fungus or mould called by scientific men Botrytis bassiana, and by the cultivators of the silkworm “muscardine” and "gættino.” Any one can verify this fact by rubbing a silkworm with a camel’s hair brush previously brought in contact with the spores of this cryptogamic plant. It is estimated that in France, alone, the loss occasioned by this disease amounts to twenty million of francs, or 3,960,000 dollars. When, where, and how it first originated, no one knows; but it seems very probable that circumstances similar to Tucker’s hot-bed culture gave rise to it, The people first attributed the phenomenon to witchcraft.

In this connexion I will mention circumstances that came under my personal observation, showing how, sometimes, unexpected causes contribute to the rapid and unexplained formation of fungi or mould. In a village near Zurich, some twenty years ago, great excitement was caused in a farmer’s house, where every article of food containing much starch, such as potatoes, flour dumplings, and rice, turned red in spots when brought to the table, as if sprinkled with blood. A neighboring family was charged with wickedly causing this trouble. So. great became the excitement and popular prejudice against the accused, that the police had the matter investigated. Experiments confirmed the truth of the supposed blood-stains appearing upon cooked starchy vegetables, and the cause was traced to a sewer passing under the kitchen. It was probably the parasite known as the “bloody wonder,” Prodigium farinœ, on account of which many, in a superstitious age, lost their lives. According to Ehrenberg—who lately succeeded in infecting in like manner boiled potatoes, dumplings, cheese, and bread—these red spots are not the result of a fungus or mould, but are microscopic animalculæ, having voluntary motion, and are termed by him Monas prodigiosa. In 1821 this phenomenon was quite general in the Rhenish provinces. We should not. be surprised if the potato mould, Botrytis (peronospora) infestans, which made its first appearance as far back as 1842-743, both on the continent of Europe and in North America; the parasite Oïdium Tuckeri, which, from 1847 to 1860, infested the grape vine, and the Brotrytis bassiana, a plant of the same family, which threatened to ruin sericulture, by boring itself in the living silkworm, proved to be the same parasite, modified by characteristics depending upon circumstances and the difference of organisms upon which they prey.

To return to our proper subject: M. Gontier, of Montrouge, France, a distinguished horticulturist, stated before the National Central Agricultural Society that the “Frankenthal” (gross-race or Trollinger) wine stock seemed to be primarily selected by the oïdium to feed upon. It has always been first observed on this variety by Tucker and others, which shows that no other would more likely degenerate by forced culture.

Count Babo, a German wine-grower of great authority, declares that the Germans have committed the blunder of planting the "Frankenthal” grape in situations not appropriate for it, such as moist grounds, &c. But what is such a mistake, after all, when compared with a house heated by stoves, and filled with a suffocating damp atmosphere—a condition fulfilled in the art of horticulture in order to yield fruit in winter, and termed forced culture? Does not the cultivation of the grape from shoots raised in hot-houses point out the road followed by the grape disease? The oïdium was not traced first upon the wild grape, or on vigorous American varieties, on table-land, or on dry steep declivities. No; it first established itself in an English hot-house; from thence it penetrated like establishments in the neighborhood, and, acclimating itself thoroughly, next attacked the artificial vine arbors in the open air, Thence it found its way into the vineyards, and was spread by the wind in every direction. In this country the Catawba grape seems to be the only variety that has suffered by the disease, and is threatened with ruin at no distant day. The horticulturist has a striking difference indicated to him in the longevity of peach trees raised from seedlings and from buds. The ancient way of propagation furnished healthy and vigorous trees, which (although coming to maturity more slowly) often reached the respectable age of fifty years; while according to the second method, trees barely reach their tenth year without being attacked by disease and decay. Before finally speaking of the remedial agents employed successfully against the grape disease, we will give briefly a few statements of the ruinous extent to which it prevailed. The following prayer, ordered by the bishop of Montpelier, France, to be read in all the churches in the diocese, may convey an idea of the terrible ravages of the disease. The following is the translation:
   "We pray Thee, O Lord our God, that Thou wouldst deign to regard the vines with kindly eye and propitious countenance; and that Thou bestow upon them Thy blessing, that neither the terrible consequences of Thy wrath, nor any noxious disease devour them, but that unharmed and full of delight the fruit be conducted to a perfect maturity, and happily preserved for our use.”

Its prevalence in Madeira, where, probably in consequence of the isolation of the country, it did more damage than anywhere else, is thus described in the report of Dr. H. Schacht. The oïdium first appeared in Madeira in 1852, soon after the flowering season in June, attacking both leaves and the young grapes, and destroying the first year nearly the total crop. In the following year it was scarcely less injurious in its effects, and, with the exception of the summer of 1856, no wine was produced on the island from 1852 to 1857. As late as.1850 the wine crop, according to the tax levied upon it, amounted to 12,9644 pipes, though in the judgment of those best informed it was double this quantity, yet in 1856 only 200 pipes were raised. No kind of grape escaped in Madeira, even the American grape, Vitis vulpina, which before 1856 did not suffer, likewise became affected. From an oral statement of Mr, Acevede, major of the engineer corps at Funchal, the disease had shown signs of its presence long before this time in Madeira, since old leases from the west of the island Ponta do Sol contain this article of agreement: that if the grape should become diseased with a white bloom, the contract should be considered annulled. In Portugal, also, some evidence of the grape disease has been perceived, but to a less extent. The vine is raised in the southwest of Madeira upon espalier frames, formed with canes fastened horizontally, four or five feet above the ground, to wooden beams or wall posts. Under the shadow of this vine roof sweet potatoes and other useful vegetables are planted. Before 1852 the largest portion of the country around Funchal, as well as the western portion of the island, is said to have been covered with vine espaliers. In 1857 these were seen only here and there, Still later, the wine stock has been entirely neglected, and in its stead sugarcane and cochineal have been planted. In the northern portions.of the island, producing an inferior kind of wine, and where, consequently, less labor was bestowed upon its culture, the vine climbs upon trees, mainly chestnut. Vine espaliers were never seen here, and although the disease affected some isolated leaves, it never attacked the grape. The 200 pipes mentioned as the product of 1856 were derived exclusively from this portion. It will thus be seen that the consumption of Madeira wine has rapidly diminished, and that that which is now sold as such is not genuine.

In 1831, Great Britain imported 209,127 gallons or 3.57 per cent. of her total wine consumption from Madeira, while in 1861 it amounted to only 28,749 gallons or 0.27 per cent. Schacht calculated the annual loss of the island from the oïdium to be 1,137,990 dollars. The Madeira is replaced in part by the various wines of the South Canary islands, or the proper Canaries, via: Teneriffe, Canary, Lanzerote, Fuerteventura, Palma, Gomera, and Ferro. These are situated nearer to the tropics and the African continent than the North Canary group, and all cultivate wine. In the middle ages Canary wine was already celebrated. We need only allude to the inn at Eastcheap, and Sir John Falstaff, to show that even at that time the wine of the Atlantic islands was known and prized. The total crop of the seven islands formerly amounted to over 25,000 pipes. The grape disease has diminished the wine product of the Canaries one-tenth. The same is the case with the Western or Azoric islands, which the writer of this article visited in 1849-50. The soil, like that of the Canaries, is entirely volcanic, and probably but a few inches deep; to prevent it from being blown off by the wind, the vineyards are divided by stone walls into small squares, and produce enormously, a bottle of fine wine. selling for about four cents. The island of Pico alone yielded annually from 15,000 to 30,000 pipes of wine. Also the other islands, Terecira, St. Miguel, Payal, St George. and Graciosa, produced splendid wines principally exported to: North America and Brazil. Vigorous efforts have of late been made to again increase the wine culture in these western islands.

REMEDIES FOR THE GRAPE DISEASE.

In the face of the wholesale destruction of so important a plant as the vine, numerous means were resorted to, purporting to be effectual in arresting the ravages of the disease. Two of these were successfully employed. The use of the first, Viz. pulverized sulphur, is attributed to an English gardener at Leyton, named Kyle. M. Gontier, near Paris, has improved the efficacy of the remedy by inventing a small hand-bellows, by means of which the powder is forcibly ejected. When signs of the disease show themselves, sulphurization is resorted to at once. It is a good plan to apply the sulphur when the leaves and°fruit have previously been covered with dew, or sprinkled with water. The berries which are already affected at this time remain stationary, while the remainder attain maturity without any farther:trouble. Microscopical examinations have revealed the highly interesting fact, that in the vicinity of every sulphur granule the cellular texture of the oïdium withers and dries up; farther, that spores already ripe are destroyed, and that others are no longer developed. In what way the sulphur acts it is difficult to explain, considering: its insolubility in water. Whether a gradual oxidation and formation of sulphurous or sulphuric acid ensues, or whether simply a slight volatilization of sulphur (sulphur gas) takes place, is not proved. The latter assumption gains ground from the fact that hothouse gardeners observe highly favorable results from simply strewing sulphur powder upon the heating pipes, having a temperature of 60° to 70°C = 140° to 158° Fahrenheit. Furthermore, experience has shown that during hot weather, and under the influence of the sun’s rays, a quicker destruction of the oïdium takes place. There is no good reason why solid sulphur should not, like water in the form of ice, volatilize in a small measure. However this may be; a single sulphurization is rarely sufficient to arrest the disease. Some spores escape its action, and their rapid development must be prevented by a new application within three to four weeks’ time, until the growth of the grape is perfected. This proceeding is practiced now, almost without exception, in the south of France and in Italy. The use of sulphur has become so great that the French government was induced to lessen the duty considerably on its importation. Although sixteen pounds of sulphur may suffice for nearly two acres of grape-vines, yet its consumption in this way almost equals the quantity employed in the manufacture of sulphuric acid and of gunpowder. By the systematic use of sulphur for years past, the oïdium has been almost entirely annihilated; and it is asserted, besides, that sulphurization promotes essentially the increase in fruit, (as also in the case of fruit trees,) but in this respect the effect may be equalled by substitutes in powder form, as, for example, the dust from the roads. Experience long since taught that fruit trees and vineyards bear most plentifully when situated on much-frequented and dusty roads.

TREATMENT OF THE VINES WITH HYDRO-SULPHIDE OF LIME.

Doctor Turrel, during the first days of the month of June, 1852, noticed the appearance of the oïdium Tuckeri on his own farm, comprising about thirty acres, in the district of Toulon, France, and resorted at once to the use of hydrosulphide of lime. The first trial proved successful. The leaves turned green once more, and the berries resumed their former brightness. The sprinkling was then resumed; the weather at the time was calm, and the atmosphere warm and sultry. The method of proceeding was as follows: Two men carried, by means of two long poles, a wooden vessel containing about twenty-five quarts of hydro-sulphide of lime; the liquid was poured into buckets, and passing along each row of vines, the leaves: and grapes were sprinkled by means of a broom dipped into the mixture. Those branches which were prostrated on the ground were raised and brushed over with the broom. Cypress brooms proved the best.

Recipe for preparing hydro-sulphide of lime.—Flowers of sulphur, 68 ounces; lime nearly slacked, same quantity; mix and knead together thoroughly; add three to four quarts water. Boil the whole in an iron kettle for about ten minutes; allow it to settle, and decant the liquor. Preserved in well-corked bottles it will keep several months. In using, one quart of this preparation is poured into one hundred quarts of clear water, stirring the mixture meanwhile. With one hundred quarts, one hundred and fifty yards of éspalier may be moistened. It will be found necessary to repeat the operation two or three times before the blooming of the vines, and a last time when the berries. begin to form. There is good reason to believe that the compound formed in gas-works, by the purifying of the gas from sulphur, could be advantageously employed in the place of that mentioned above.

According to Dr. Engelmann,[118] a reliable botanist, there are two species of fungi destructive to our American vineyards, both of which he regards as different from the European parasite, Oïdium Tuckeri. The first species, Botrytis viticula, of Berkley, is very similar to, if not identical aith, Oïdium Tucker. It makes its appearance in the latter part of June on the lower downy surface of the leaves. About the same time it appears on the pedicles, and afterwards on the young berries when they are about the size of peas, or smaller. Dr. Engelmann never saw it on full-grown berries. Those attacked on their surface, or on the pedicles, soon fall off; but the most material damage is done by this “mildew” infesting the leaves, whereupon the greater part of the berries gradually turn a yellowish brown color at their base, shrivel from that point, assume a club-shape, and at last dry up entirely, still remaining adherent to the withered racemes. This is the brown rot, so well known to cultivators of grapes. The second kind, the black rot, is brought on by a very different fungus, which Dr. Engelmann thinks is undescribed as yet, that is, that it is a new species. He says it belongs near Ehrenberg’s genus, nemaspora, and ought to bear the name of ampelicida. It makes its appearance only on nearly full-grown berries, exhibiting in the first stage a discolored spot on the side, (but never at the base of the berry,) about two lines in diameter, with a dark spot in the centre. This spot soon becomes light brown, and remains so, while the surrounding part of the berry gets darker, and exhibits under the microscope a rough or pustulous surface. Gradually the berry shrivels up and becomes black. The individual fungi are little spherical bodies (from 0.07 to 0.10 of a line in diameter) formed beneath the surface in great numbers, which, developing, elevate and at last burst the epidermis. They then open at the apex by a small jagged hole, and, shrivelling with the berry, eject a more or less curled or twisted thread which, when moistened, becomes gelatinous, and shows the innumerable oval sporules, (from 0.004 to 0.005 of a line long,) each imbedded in mucilage.

Whether different species of grapes contain also different species of parasites, or whether. the same fungi, under different circumstances, relating to food and meteorological alterations, assume a different form, the writer must leave undecided. It is true, that in the animal kingdom the different species foster different parasites, so much so, that the examination of these animal parasites often aids in the determination of the species.

To return to the grape disease. We guard against its attacks on this continent by precisely the same means as suggested for a cure in Europe—that is, by the use of sulphur.

In Dingler’s: Polytechnic Journal; vol. OL, Ed. 1858, p. 146, is the following extract from M. Marès in regard to experiments upon the grape disease:
   "The following advice in the treatment of diseased vines will prove of great advantage:
   “1. The diseased vine needs special care, the ground well cultivated, loose, and porous, no weeds. Everything that impedes the growth favors the development of the disease, as bad pruning, insufficient hoeing, &c., &c.
   “The appearance of the fungi destroys the growth. This must, through fostering care, be restored, and sulphur applied against the oïdium.
   “2. It is better to apply sulphur too early than too late.
   “3. Sulphurization of the plant at the flowering season proves the most effective. At this stage it seems to have a salutary effect upon the growth also. I thought that I observed in 1854-’55 that vine stocks that had been sulphurized bore better than others not so treated.
   "4. The sulphur must be applied carefully and thoroughly to all parts—the wood, the leaves, flowers, and fruit, and must not be sparingly applied. The powder is blown upon the plant from two opposite directions while passing entirely around it. The application has been effective when the leaf or fruit held towards the light appears covered with the sulphur-dust. We must not overlook the fact that sulphur destroys the oïdium only by being brought in contact with it.
   "5. A vineyard that has been recently sulphurized must remain at least several days before hoeing, The flour of sulphur falling to the ground in part volatilizes by the hot rays of the sun and condenses on the shady parts of the vine stock. In this way the sulphur may reach many points that have escaped the blowing process, and this advantage would be lost in burying the sulpbur by too soon hoeing.
   "6. If the sulphur is dissolved or dissipated by the wind and rain on the same day it is applied, we may wait several days before a second sulphurization; for the first supply, in spite of the rain, is effective, provided the temperature is 16° to 20° R. = 68° to 77° Fahrenheit. If the vine stock is well supplied with leaves, as in July, a strong heavy rain does not prevent the effect of the sulphur, for it adheres so firmly to the surfaces diseased with the oïdium that water can only carry it off together with the fungi or mildew. In this respect a rain does no harm after the 1st of July.
   “7. The requisite sulphurization should not be postponed on account of the wind, but more sulphur should be applied than in calmer weather. I have sulphurized vine stocks that were but little developed in the month of June, and they did well.
   “8. The effect of the sulphur may be judged of in the course of ten days after the operation, (for we must allow time for the growth to assume a normal condition and develop itself.)
   “9. Sulphur is no absolute protection against the disease, for it does not prevent its formation, and the process has to be repeated at regular intervals. It acts more as a remedial agent than as a preventive, and we must, therefore, wait for the first signs of the disease before we resort to sulphur, so as not to apply the remedy uselessly.
   “10. After the tenth of August, in the climate of Montpelier, France, the effect of sulphur upon the blue grape that has been seriously affected with the disease is no longer perceptible. If the disease is absent until the formation of the fruit, there is less liability to its occurrence; but if it happens to attack the plant and fruit at this stage, the remedy is less effective.

"From the preceding instructions it will be seen that the timely application of sulphur before and after July 15 (taking this date as the mean) will protect the vine from the oïdium until the ripening season. Experience has annually established this fact since the appearance of the grape disease.

"In the department of Herault, France, the formation and development of the fruit takes place from the fifth to the twenty-fifth of August. Any time of the day will answer to apply the sulphur, in case it does not rain, but it produces the same effect upon either a dry or moist surface; and if the temperature is not below 20° R. = 77° Fahrenheit, it will destroy the oïdium when brought in contact with it. The most favorable circumstances for applying the sulphur, to act — and effectively, are a warm sunny day and a gentle breeze, aiding the distribution of the sulphur, and enabling” the surfaces to receive it. It adheres firmly where the oïdium develops itself, for the latter presents a velvet-like surface that receives and tenaciously holds the flour thrown upon it.

“My annual use of sulphur per hectare, (2½ English acres,) was in the month of May, 15 kilograms, (= 30 pounds;) June, 50 kilograms, (= 100 pounds;) July, 70 kilograms, (= 140 pounds;) costing me, together with the labor, (performed by women,) 50 francs and 44 centimes, (= to less than ten dollars.)

“If the sulphur used is fine, (like flour of sulphur,) it spreads better and less is required.”


EXPLANATION OF THE PLATES AND FIGURES.

Plate I.
fungal thangs

Figure 1.—a a, webby, sterile filaments, or mycelium; b b, fertile, erect, and articulated filaments; c c, spores, or seeds, in a condition of vigorous vegetation.
Figure 2.—Three spores having reached their maturity simultaneously.
Figure 3.—a a, mycelium at different stages; b b, erect branches.
Figure 4.—a a, sterile filaments of mycelium at the left hand; c c, spores adherent and detached, according to Dr. Montagnie.

Plate II.
Figure 1.—Small grape of retarded growth and infested by the oïdium.
Figure 2.—Fragments of this grape as it looked when inspected, October 16, 1852; a a, mycelium; b b, erect filaments; c c, spores. The oïdium appears weakened; the filaments are drooping. Temperature rather cool.
Figure 3.—d d, fragments of dried up filaments.

Plate III.
Figure 1.—a a, fragments of the pellicle of an infected berry, but free or disentangled from the oïdium. The thin slice of the berry exhibits the elevated points described in the text; b b, cells of the pulp below the pellicle.
Figure 2.—d d d, fragments of the dried up mycelium. When placed in a moist atmosphere, below 59° Fahrenheit, they throw out radiating filaments, a a a.

Plate IV.
Figure 1.—Herbaceous fragment covered at a a with black spots.
Figure 2.—Woody fragment in August, showing reddish spots, having remained stationary since the invasion of the oïdium.
Figure 3.—Fragment of a growing berry, appearing punctured when freed from the mycelium.
Figure 4—Small portion of a bunch of grapes partially infected at the beginning of the disease—the first of July.
Figure 5. Two berries, the pellicle of which bursted longitudinally; a third exhibits the radiating points; the mycelium has disappeared.

The observations and drawings of Plates 2, 3, and 4 were made by Guérin Ménéville. The first three plates represent the objects magnified 400 diameters.