Page:Popular Science Monthly Volume 5.djvu/180

 cause of their failure. Take as an instance the case of the Catawba. It is in growing demand in the Mississippi Valley, as, so far, the best white-wine grape, and the only one extensively used in the manufacture of sparkling wines. Yet it is, in this part of the country, one of the most susceptible to the Phylloxera disease, and its successful growth becomes more and more uncertain. If by a thorough understanding of the disease, and by the system of grafting which I have suggested, this vine can be successfully grown in the Mississippi Valley, it is safe to say that the value of our vineyards will be doubled; as the Concord, which is now the main reliance, and which makes but an inferior wine, has already so glutted our markets as scarcely to pay the grower.

—Without going into particulars, several good reasons may be given to explain the fact that Phylloxera is more devastating in the vineyards of France than in our own. There exists a certain harmony between the indigenous fauna and flora of a country, and our native vines are such as from their inherent peculiarities have best withstood the attacks of the insect. The European vine, on the contrary, succumbs more readily, not only because of its more tender and delicate nature, but because it has not been accustomed to the disease—there being, doubtless, a parallel between this case and the well-known fact that diseases and parasites which are comparatively harmless among peoples long accustomed to them, become virulent and often fatal when first introduced among hitherto uncontaminated peoples.

Then the particular natural enemies of the insect which belong to its own class, and which in this country help to keep it within due bounds, are lacking in Europe; and it will require some time before the closely allied European predaceous species will prey upon and check it there to the same extent.

The Phylloxera will, also, other things being equal, have an advantage in those countries where the mildness and shortness of the winter allow an increase in the annual number of its generations. Finally, the differences in soil and in modes of culture have no insignificant bearing on the question in hand. Though Phylloxera, in both types, is found on our wild vines, it is very doubtful if such wild vines, in a state of nature, are ever killed by it. With their far-reaching arms embracing shrub and tree, their climbing habit unchecked by the pruner's knife; these vines have a corresponding length and depth of root, which render them less susceptible to injury from an underground enemy. Our own method of growing on trellis approaches more nearly these natural conditions than that employed in the ravaged French districts, where the vines are grown in greater proximity and allowed to trail on the ground, or are supported by a single stake.