Manual of American Grape-Growing. U. P. Hedrick
a perfectly satisfactory growth."
Care in the nursery.
The grafts are planted in the nursery, and are given much the same care recommended for cuttings. They may be set in trenches made with plow or spade; or they may be planted in very shallow trenches with a dibble. After planting, the grafts are covered with an inch or two of soil, thus forming a wide ridge in the nursery row with the union of the grafts at the original level of the soil. Cultivation should begin at once and be frequent enough to prevent the formation of a crust, in order that the young shoots may not have difficulty in forcing their way through the soil. Roots start on the cions sooner than on the stock, the soil being warmer at the surface, and help sustain the cions until the stocks are well rooted, at which time all roots started on the cion are removed, and at the same time the tying material is cut if it has not rotted. Suckers are removed as soon as they show above ground. The grafts are dug as soon as the leaves fall and the young vines become dormant, after which they are sorted in three lots, according to size of top and root, and heeled-in in a cool moist place until they are to be planted.
Nursery versus home-grown vines.
The verdict of all vineyardists is that it is better to buy nursery-grown vines than to attempt to grow them. The high quality of the vines which can be purchased and the reasonable purchase price make it hardly worth while to try home-grown vines, especially since considerable investment, experience and skill are required to grow good vines.
"Pedigreed" Grape Vines
Many viticulturists, in common with orchardists, believe that their plants should be propagated only from parents which have good characters, that is, are vigorous, healthy, productive, and bear fruit of large size, perfect form, good color and good quality. They believe, in short, that varieties can be improved by bud selection. There is, however, but little in either theory or fact to substantiate the belief of those who say that varieties once established can be improved; or, on the other hand, that they degenerate. Present knowledge and experience indicate that heredity is all but complete in varieties propagated from parts of plants. The multitude of grapes in any variety, all from one seed, are morphologically one individual. A few kinds of grapes go back to Christ's time, and these seem to agree almost perfectly with the descriptions of them made by Roman writers 2000 years ago. How, then, can the differences between vines of a variety in every vineyard in the land be explained?
Ample explanation is found in "nurture" to account for the variation in vines without involving a change in "Nature." Soil, sunlight, moisture, insects, disease, plant-food, and the stock in the case of grafted vines, give every vine a distinct environment and hence a distinct individuality of its own. Peculiarities in a vine appear and disappear with the individual. A variety can be changed temporarily by its environment, but remove the incidental forces and it snaps back into its same old self.
Heredity is not quite complete in the grape, however; for, now and then, sports or mutations appear which are permanent and, if sufficiently different, become a strain of the parent variety or possibly a new variety. There are several such sports of the Concord under cultivation. The grape-grower can tell these sports from the modifications brought about by environment only by propagation. If a variation is transmitted unchanged through successive generations of the grape, as occasionally happens, it may be looked on as a new form. "Pedigreed" vines, then, should be subject to a test of several generations in an experimental vineyard before the grape-grower pays the price demanded for the supposed improvement.
CHAPTER IV
STOCKS AND RESISTANT VINES
Phylloxera, a tiny root-louse, made its appearance in France in 1861 and began multiplying with a fury unparalleled in the insect world. By 1874, the pest had become so widespread in Europe that it threatened the very existence of the great vineyard industry of that continent. All attempts to bring the pest under control failed, although the French government offered a reward of 300,000 francs for a satisfactory remedy. Numerous methods of treating the soil to check the ravages of the insect were tried, also, but none was efficacious. Finally, it dawned on European vineyardists that phylloxera is not a scourge in America, its habitat, and that European vineyards might be saved by grafting Vinifera vines on the roots of immune American grapes. At once the reconstruction of vineyards in Europe was begun by grafting the grapes on phylloxera-resistant roots. Meanwhile, consternation spread to California when it was discovered that phylloxera was running riot in some of the vineyards of the Pacific slope; however, with the knowledge derived from viticulturists in Europe, they too began reconstructing vineyards on immune roots, without the same success as the Europeans, it is true, but with such measure of success that it soon became the approved method of growing grapes in this great region.
Through the use of resistant stocks, phylloxera is now defied in Vinifera regions. Millions of American stocks are annually struck at home, in Europe and wherever Vinifera grapes are grown, to be top-worked with varieties susceptible to phylloxera. Seldom has mastery over a pest been so complete; but, to triumph over the tiny insect, the industry has had to be revolutionized. Resistant stocks, in their turn, brought innumerable new problems, many of which are still unsolved. Investigations and experiences in rehabilitating vineyards have been carried on for forty years, the results set forth in books and bulletins and yet there are many problems to be solved. The grape-grower in regions infested with phylloxera is always under the necessity of taking advantage of the latest demonstration of practices in the use of resistant stocks. These practices are best studied in the experiments of state experiment stations and the United States Department of Agriculture, and in the vineyards of leading grape-growers, since even those most needing elucidation can be but briefly discussed in the following paragraphs.
The wild vines of a species are always seedlings and are hence exceedingly variable. The first vineyards of resistant stocks were vines grafted on stocks of wild vines, and the results were very unsatisfactory; for, naturally, there was divergence in many characters and especially in the vigor of the vines. Also, there was difficulty in grafting, since some wild vines are stout and others slender; some bear grafts well, while others do not. It soon became apparent that to succeed, varieties must be selected from the different species for vineyard work. The great task of the experimenter and grape-grower, therefore, has been to select varieties of the several species sufficiently resistant, vigorous and otherwise possessed of characters fitting them to become good stocks. Out of vast numbers tested, a few are now generally recognized as best for the several groups of Vinifera grapes and the several distinct regions in which these grapes are grown.
Resistant species and varieties.
The reconstruction of phylloxera-ridden vineyards by the use of resistant stocks is possible only because some species and varieties are, as has been said, more resistant to the root-louse than others. All degrees of resistance exist, as would be suspected, from immunity to great susceptibility. It is obvious that the foundation of the art of growing resistant vineyards is exact knowledge of the immunities and susceptibilities of the many varieties and species of grapes. From the first use of resistant vines, experimenters everywhere have set themselves at work to determine not only what the most resistant vines are, but what the causes and conditions of immunity. In spite of a wealth of empirical discoveries as to what grapes can best resist the root-louse, causes and most of the conditions of immunity are still little understood. Definite, useful knowledge, so far, goes little further than the establishment of lists of species and varieties, the latter subject to change, that are most useful in setting resistant vineyards.
Phylloxera does little damage to species of Vitis native to the same general region in which the pest has its habitat, but nevertheless there are some differences