Manual of American Grape-Growing Part 20

[Ill.u.s.tration: FIG. 45. Grapes attacked by downy-mildew.]

Downy-mildew, like black-rot, spreads most rapidly and does most injury in hot, wet weather. As with practically all diseases of the grape, much can be accomplished in the way of control of the disease by destroying infested leaves, shoots and berries which contain the winter spores, but these sanitary measures are not sufficiently effective and vineyards must be sprayed as recommended for black-rot, except that the first application should be made before the blossom-buds appear.

_Powdery-mildew._

Less troublesome than downy-mildew in the East, powdery-mildew (_Uncinula necator_), unless checked, is capable of destroying the entire crop of European grapes on the Pacific slope. In the East it sometimes causes great loss on the several varieties known as "Rogers hybrids" and, curiously enough, is often a rather serious disease of the Concord. The disease is caused by a superficial fungus which pa.s.ses the winter on fallen leaves and also on the canes. The spores begin to germinate a few weeks after the grape blossoms, but the disease is not often found until the grapes are nearly half grown. The fine white filaments of the fungus, which const.i.tute the vegetative portion of the parasite, then attack the leaves, shoots and fruit, sending up short irregular branches on which great numbers of spores are borne. These give the upper surface of the leaf a gray, powdery appearance, hence the name. Eventually the diseased leaves become light brown and if the disease is severe, soon fall. Infected berries take on a gray, scurfy appearance, speckled with brown, are checked in growth and often burst on one side, exposing the seeds. The berries, however, do not become soft and shrunken as when attacked by the downy-mildew. The disease pa.s.ses the winter in resting-spores produced late in the growing season. Powdery-mildew differs from other fungous diseases of the grape in being more prevalent in hot, dry seasons than in cold, wet ones.

In eastern America powdery-mildew is controlled by the treatment recommended for black-rot. When black-rot is not prevalent, two sprays with bordeaux mixture are recommended; the first in early July and the second about two weeks later. On the Pacific coast, however, powdery-mildew or "odium" as it is often called there, the name coming from Europe, is more cheaply and more successfully combated by dusting with flowers of sulfur. Dusting is often done by hand or with perforated cans but this is wasteful and uncertain, and any one of several sulfur-sprayers may be used which does the work better.

_Anthracnose._

Another widespread disease is anthracnose (_Sphaceloma ampelinum_), called "birds-eye-rot" because of the peculiar spots produced on the affected fruits, which attacks leaves, shoots and fruits of the vine.

It first appears on the leaves in small, irregular, dark brown sunken spots with a dark margin. Later it appears on the fruits, having much the same appearance though the spots are usually larger and more sunken, the disease being most characteristic on the fruit, however.

Frequently two or more spots unite and so cover the greater part of the berry. The fruits become hard, more or less wrinkled, and the diseased area often ruptures, exposing the seed, much as with powdery-mildew. The spores of the fungus are produced in great numbers on diseased areas during the growing season and are borne on thread-like filaments which live throughout the winter in the tissues of the vine and are ready for new growth in the spring. Winter-spores have not yet been discovered.

Anthracnose is widely distributed in eastern America but seldom causes great or general loss, most of the commercial grapes being relatively immune to the disease. A few sorts rather commonly grown in home vineyards, as Diamond, Brighton and Agawam, suffer most from anthracnose. Spraying with bordeaux mixture, as recommended for black-rot, is usually sufficient to keep the disease in check.

_Dead-arm disease._

A troublesome disease of recent appearance is now doing considerable damage in the Chautauqua grape-belt along the sh.o.r.es of Lake Erie, being most common on the Concord. From the fact that it is usually found on one arm of the vine it is called "dead-arm disease"

(_Cryptosporella viticola_.) The disease is caused by a fungus which pa.s.ses the winter in small, black fruiting bodies in the dead parts of the vine. Early in the spring the fungus spreads by means of spores to the young shoots and later in the season attacks mature berries, producing small, black, oblong spots of black-rot. Sooner or later, if the diseased shoot is not cut off, the fungus spreads to the arms or trunk of the vine, producing a slow, dry rot which eventually kills the affected part. Fortunately, the presence of the disease is quickly detected by small yellowish leaves, much crimped about the margin.

The fungus is easily controlled by marking the diseased arms when the first symptoms appear and cutting these off at pruning time. If the vine is much mutilated by such pruning, usually suckers can be brought up from beneath the surface of the ground to renew the vine. The applications of bordeaux mixture recommended for black-rot are valuable in preventing the dead-arm disease. The disease is largely prevented by renewing the old wood of the vine as soon as the trunk begins to show a gnarled appearance.

_Sh.e.l.ling._

In eastern America, especially in the Chautauqua grape-belt, grape-growers not infrequently lose a large part of the crop by the premature falling of the grapes from the stems. The trouble is an ancient one and is designated as "sh.e.l.ling" or "rattling." This premature dropping usually begins at the end of a cl.u.s.ter, and cl.u.s.ters farthest from the trunk are earliest affected. When vineyards suffer badly from this sh.e.l.ling, the vines often take on a sickly appearance, the foliage falling off in color and the outer margins of the leaves drying up more or less. The fallen fruit has an insipid taste and is, of course, worthless even if it could be harvested.

The cause of the trouble is not known. Grapes may "rattle" on high land or low land, on poor soil or rich soil, on heavy or light soil. A vineyard may be affected one year and not the next. Grape-growers usually attribute the trouble to faulty nutrition, but applications of fertilizers have not proved a preventive. Old and well-established vineyards seem freer from the trouble than new and poorly established plantings. The most reasonable theory as to the cause of sh.e.l.ling is that it comes from faulty nutrition of the vine, but the conditions so affecting the nutrition are not yet satisfactorily determined.

_Diseases of minor importance._

Ripe-rot or bitter-rot (_Glomerella rufomaculans_) is a disease due to the same fungus causing the bitter-rot of the apple. As the name indicates, the disease usually appears on the fruit at ripening time and under favorable conditions continues after the grapes are picked.

It may also attack the leaves and stems. The first indication of the fungus is the appearance of reddish-brown spots which spread and eventually cover the whole fruit. The berries do not shrivel, but the rotted surface becomes dotted with pustules in which the spores are borne. It is hard to tell how much damage this disease does, but it is not usually great and the late applications of bordeaux mixture for black-rot or powdery-mildew are very effective in controlling it.

Crown-gall, now known to be a bacterial disease which causes knots or galls on the roots of various wild and cultivated plants, sometimes attacks grape roots or even the vines above ground. Occasionally, the disease is rather serious, but it is not often to be reckoned with in the vineyard regions of America. Fungicides are useless in combating the disease and all that can be done is to exercise great care in planting infected stock. It is doubtful whether crown-gall ever seriously injures vines in northern regions, although it may occasionally do so in the South.

In California there is a somewhat mysterious disease known as "Anaheim disease," because of its having first made its appearance in the vicinity of Anaheim. As near as can be learned, the disease first appeared in 1884 and then spread rapidly from forty to fifty miles from the point where it began its ravages, causing direct and indirect loss of many millions of dollars, and leading to the abandonment of grape-growing in some parts of southern California. Fortunately, in recent years the Anaheim disease is less aggressive but still does more or less damage. The nature and the treatment of this disease are not as yet fully determined, although several experimenters are studying the trouble. Californians whose vineyards suffer from this disease should apply to the experiment station at Berkeley for the latest information in regard to it.

Coulure is another trouble of the vine in California of which little is yet known, either as to cause or treatment. The term signifies the failure of the fruit to set or to remain on the cl.u.s.ters. The trouble occurs in varying degrees from the loss of a few berries to the complete sh.e.l.ling of the fruit from the stem. It is worse in some localities than others and in some varieties than others. Various causes have been a.s.signed to the disease, chief of which, and most probable, are unfavorable climatic conditions.

CONTROL OF INSECTS AND DISEASES

From the number of insects and diseases found on the grape, it would seem that, literally, "pestilence walketh in darkness and destruction wasteth at noonday" in the vineyards of the country. But not many of the ills that grape-flesh is heir to are ever found in one region, and the vineyard is seldom attacked by many diseases or insects in a single season. There was a time, as we have said before, when grape-growers were so beset by pests which they could not control, that viticulture was one of the most uncertain fields in agriculture.

But one brilliant discovery after another has brought the pests of the grape under the hand of man until now there are but few that need cause much expense in treatment or worry as to the outcome.

Plants cannot be attacked by diseases unless infection is permitted.

It follows that by proper sanitation most of the insect pests of the vine can be kept out of the vineyard.

_Vineyard sanitation._

By changing or modifying environment, immunity can be secured from many of the pests of the grape and damage may be reduced with most if not all. Cultivation, as has been noted under several insect pests and one or two of the diseases of the grape, is an effective method of eliminating grape pests. In the case of insects, it destroys the insects themselves and the hibernating places as well. The vineyard should never be kept in sod, but always under thorough and frequent cultivation. Vineyard sanitation is greatly improved, also, if cover-crops which remain green during the winter are planted after the last cultivation. Cultivation should usually be preceded by deep plowing in the fall or spring to turn under fallen leaves and weeds or gra.s.s in which hibernating insects may pa.s.s the winter.

The surroundings of the vineyard should be looked after. Fence-rows and waste lands which cannot be cultivated may often be burned over to destroy the hibernating places of grape insects. As a rule, it is unwise to plant the bramble berries or even strawberries in vineyards, or adjoining vineyards, since these plants afford hibernating places and food plants for some of the grape insects, especially the destructive leaf-hopper. Lastly, precaution should be taken by destroying all wild grape-vines near vineyards, as these frequently harbor insects and diseases, the flea-beetle finding the wild grape-vine almost a necessity to its existence.

_Spraying._

Definite rules cannot be laid down for spraying vineyards the country over. The literature on this subject is plentiful in any state in which grapes are largely grown, within the reach of the grape-grower, and is not difficult to understand once it is in hand. Every grape-grower should secure and study the publications of the state experiment stations having to do with the control of insects and diseases.

The number of applications and the sprays to be used vary greatly in different parts of America. On the Pacific slope the only application yearly required in most vineyard regions is dusting with flowers of sulfur for powdery-mildew. Several other pests may, however, from year to year, or in one locality or another, require special treatment. In the grape regions of New York, many grape-growers do not spray at all, but these are usually slovens or procrastinators whose profits are small and uncertain. In the grape regions of the northeastern states, orderly vineyardists spray at least once with bordeaux mixture (4-4-50) in which is put three pounds of a.r.s.enate of lead, no matter how few insects and fungi are present. This treatment is given soon after the blossoms fall. In more southern regions it may be necessary to make a similar treatment soon after the first leaves appear, again after the blossoms fall and every two weeks thereafter until the grapes begin to turn in color, making as many as four, five or even six applications in all. To these regular applications of bordeaux mixture and a.r.s.enate of lead, contact insecticides, as some of the nicotine preparations, may have to be added; or, for special purposes as specified in discussing the several pests, cheap mola.s.ses is added.

It is doubtful, however, whether the grape can be grown with commercial success where insects and fungi prevail and are so pestiferous as to require annually more than two or three applications of spraying mixtures.

[Ill.u.s.tration: PLATE XVIII.--Herbert (2/3).]

CHAPTER XIII

MARKETING THE CROPS AND VINEYARD RETURNS

Viticulture, as all divisions of agriculture, is made up of two quite distinct phases of activity: growing the crop and marketing the crop.

The subjects to be treated in this and the next chapter belong rather more to marketing than to cultural activities. Treated in detail, these operations const.i.tute matter sufficient for a separate treatise, and only an outline of present practices is in place in a text such as this devoted to the culture of the fruit. The several operations to be discussed are picking, packing, storing, shipping and marketing.

HARVESTING IN THE EAST AND NORTH

As the consummation of the care of the vine, the in-gathering of the crop is celebrated in all European countries with rejoicings in song, dance and mirth. In America the vintage is less of an event than in Europe, but it is more picturesque and diverting than the harvest of most other crops. It is work in which youth and old age, as well as those in the prime of life in both s.e.xes, can take part and is reputed as a most healthful occupation. For these reasons, the grape harvest in America, as in Europe, has somewhat the air of a holiday, so that workers are usually readily found for the several operations of harvesting. Laborers come as grapes begin to ripen from near-by cities and towns and neighboring country-sides in such numbers that the care of the crop is speedily accomplished.

_Pickers._

As a rule, pickers are hired by the piece rather than by the day, experience having demonstrated that so paid they do more and better work. There is usually much diversity in race, age and condition of life of pickers so that harmonious and efficient work is scarcely possible without a competent foreman in charge who must often be a.s.sisted by a sub-foreman. Efficient supervision doubles the picking capacity of a gang of workers, and, moreover, is necessary to see that the fruit is picked and packed with proper care. In hiring pickers, it is usually stipulated that a part of the pay is to be reserved until the close of the season; otherwise those disposed to have a holiday leave when the weather becomes unpleasant or seek greener pastures when the grapes become scarce.

_Time to pick._

Unlike some fruits, grapes must not be picked until they are fully ripe, as unripe grapes do not mature after picking. Grapes not matured lack the necessary percentage of sugar and solids to keep well and have not developed their full flavor. Many growers make the mistake of sending grapes to the market before fully ripe, a mistake easily made with some varieties because they acquire full color before full maturity. Color, therefore, is not a good guide as to the time to pick. In the northern and eastern states, late varieties of grapes may be allowed to hang on the vines for some little time after maturity, the late autumn suns giving them a higher degree of sweetness and perfection. Some growers run the risks of light frosts to further maturity and to secure the added advantage of the removal of many leaves from the vines. Ripeness is indicated by a combination of signs difficult to describe but easily learned by experience. These signs are: first, a characteristic color; second, full development of flavor and aroma; third, a softer texture of the pulp and a slight thickening of the juice so that it is more or less sticky; fourth, the ends of the stems turn from green to brown; fifth, the berries pull more readily from their stems; sixth, the seeds are free or more nearly free from the pulp and usually turn from green to brown.

_Picking appliances._

But few appliances are needed in picking grapes. Shears are a necessity. These are of special make and can be bought from dealers in horticultural supplies, costing from 75 cents to $1. Some growers, after picking, pack the fruit in the field in the receptacles in which it is to go to market. The greater number, however, pick in trays which are taken to the packing-house and allowed to stand until the fruit is wilted before packing for shipment. Trays may be of several sizes and shapes, but are usually shallow flats holding from twenty-five to thirty-five pounds. The picked fruit is taken from the vineyard to the packing-shed in a wagon with flexible springs to prevent jarring and jolting. Large growers usually have specially built one-horse platform wagons, the front wheels of which pa.s.s under the platform.

_Picking accounts._

It is no small matter to keep a picking account with pickers.

Business-like growers use one of several kinds of tickets or tags in keeping accounts. Probably the most common method is to give a ticket to the picker when the receptacle of grapes is delivered, the grower either keeping half of the original or a duplicate of it. Objections to ticket systems are that the pickers often lose the tickets, are irregular in returning them, or exchange them with other pickers. To obviate the disadvantages of tickets, some growers use tags which bear the picker's name and are attached to his person. These tags have marginal numbers or divisions which are canceled by a punch as pickers deliver the grapes. Still another method is to keep book accounts with each picker in which case payment is made by the pound, each receptacle being put on the scales as brought in from the field, credit being given for the number of pounds. It is the duty of those in charge to see that each picker finishes the row or the part of the row to which he is a.s.signed, and that he does not wander over the vineyard in search of the best picking.

_Packing-houses and their appliances._