ON THE CAUSE OF DETERIORATION IN SOME OF
OUR NATIVE GRAPE-VINES, AND ONE OF THE
PROBABLE REASONS WHY EUROPEAN
VINES HAVE SO GENERALLY
FAILED WITH US.

BY C. V. RILEY.

THE GRAPE-LEAF GALL-LOUSE (Phylloxera vitifolia† Fitch.).The experience of the past year, enables me to add much of interest and importance to last year's account of the above insect. This experience has already been made public in an article published in the " Rural New Yorker," and reproduced in the "Rural World" of St. Louis. I am pleased to know that the views there set forth receive the indorsement of such an experienced and practical man as Mr. Geo. Husmann, the well known grape authority in our State, and editor of the vineyard department of the last named journal.

It is well known that nearly all the varieties of the European grape-vine (Vitis vinifera) have, in the end, proved valueless when introduced and cultivated in the eastern half of the United States. The majority of them grow well at first, and a few exceptional cases might be mentioned where some of them, such as the Black Hamburg and Chasselas, have even fruited successfully for many years, especially when isolated or trained against walls; while

*We copy this from Mr. Riley's 4th Report as Entomologist to the State of Missouri, 1872, and have to thank Mr. Riley for the use of the cuts.-EDS.

This is the specific name by which I last year gave an account of this grape-vine insect; and I employ it again for that very reason, and for the further reason that it is the name most familiar to the American reader. I have already given my opinion (3rd Rep. p. 95, note) that though the name is objectionable, it ought perhaps to be retained. It is doubtful, however, whether many other entomologists will agree with me; and while I believe in carrying out the "law of priority" to its fullest extent, consistent with reason, there are many cases where it must give way to that of "accord." The present is, perhaps, just such a case; for aside from the technical objection, Dr. Fitch knew so little of the insect's true characters, when he named it, that he cannot be said to have described it, and did not refer it to its proper genus which was already erected to receive it. His name will, therefore, doubtless give way to that of Phyl loxera vastatrix, which Planchon first gave to the root-inhabiting form, and which has generally been recognized abroad. The same may be said of Westwood's name Peritymbia vitisana, which was also proposed for the same insect in 1868, in a communication to the Ashmolean Society of Oxford, England.

But

they more generally do well when isolated in cold houses. the general truth of the first statement holds good. It is also well known that some of our native vines, which for a while were universal favorites on account of their productiveness, vigor and other excellent qualities, have of late years sadly deteriorated. Among such the Catawba was for a long time the popular grape ; but its cultivation is now entirely abandoned in many parts of the Mississippi Valley, and even at Hammondsport and other parts of New York, and Nauvoo, Illinois, where it is still largely cultivated, I learn from experienced grape-growers that it is fast on the decline.

This deterioration-this failure, has been attributed to a variety of causes, for in the absence of anything definite and ascertainable to keep it within bounds, the speculative turn of our minds is sure to have full scope, and grasping at every shadow of probability, leaves no possible theory unsearched. As in all such cases, also, the mind gets lost in, and is satisfied to vaguely rest with, the theory least provable; and to some occult and mysterious change of climate we are at last satisfied to attribute the change though, if the meteorological records were carefully examined, they would probably show no difference in the mean annual condition of our climate during the past half century.

It is very natural to suppose that vines of European origin should be less hardy in this country than our native varieties, that as in the case of the Spanish Chestnut, the English Gooseberry, etc., etc., there is something in our climate which precludes their flourishing as well here as there. I would by no means deny that such is the case, for it is this very comparative tenderness which predisposes them the more to the destructive agent of which I am about to speak. Yet when we consider that in some

parts of Europe, where the Vine flourishes, the extremes of heat and cold are as great as here; that we possess a great variety o soil and climate, and that by covering and other modes of protection in winter, we may, where necessary, counteract the rigor

of the latter — it would appear that we certainly have attributed too much to climatic influence: and such a view is strengthened by the fact that our native varieties, if free from the insect which forms the subject of this article, usually do well when cultivated in Europe, and further that the Vitis vinifera is not a native of Europe, but of western Asia.

The above reflections are of a general character, but

apply more partic

ularly to the great

J

Grape Gall-louse: a, winged female; 6, her tarsus, c, egg, d, the which is admitted

newly hatched gall-inhabiting type, ventral view; e, dorsal view; f

section of a gall; g, the tubercled root-inhabiting form; h, the to be, in many

mother gall louse at the height of her fertility, ventral view; i, dor

sal view; j and k, differently veined wings of the Oak Phyllorera parts, eminently

from Europe. All these figures are greatly enlarged, the natural size being shown by the hair lines at the side of each.

soil and climate, to the cultivation of the Vine.

adapted, both by

One of the reasons why the European vines do well in California, outside of and beyond the more favorable clime in that portion of the continent is, no doubt, because the insect which here affects them, like many other species common on this side of the Rocky

Mountains, has not yet crossed to the other side. If such is the case, our California neighbors should take warning from Europe, and guard, if possible, against an invasion.

The announcement that I have at last ascertained one of the principal causes, if not the sole cause, of this decline, and that, knowing the cause, we may in a measure obviate it, will doubtless cause many a grape-grower to wonder. Some may even pooh-pooh the idea, and deem it impossible that they have so long remained in ignorance of so important a fact, that a "bug-hunter” should discover it at last. Let the facts speak.*

This destructive agent is none other than the little insect we are now treating of.

The general history of the louse, and the habits of the gallinhabiting type were sketched in my last Report, and need not be repeated.

FURTHER PROOF OF THE IDENTITY OF THE AMERICAN INSECT WITH THE EUROPEAN.-That the two are identical there can no longer be any shadow of a doubt. I have critically examined the living lice in the fields of France, and brought with me, from that country, both winged male and female specimens, preserved in acetic acid. I find that the insect has exactly the same habits here as there, and that winged specimens which I bred last fall from the roots of our vines, accord perfectly with those brought over with me. In the different forms the insects assume, in their work, and in all other minutia, the two agree.

WHY I CONSIDER THE GALL-LOUSE AND ROOT-LOUSE IDENTICAL. -First, wherever this insect has been noticed in England, both the gall-inhabiting and root-inhabiting types have been found. In France, the galls occur abundantly on such of our American

*It is really amusing to witness how the facts here set forth have been received by hose who never spent ten minutes' investigation of the subject in their lives. In the silkworm disease that has of late years been so prevalent in Europe, M. Pasteur, after the most painstaking and elaborate experiments, at which he sacrificed his health, unrayelled its mysteries, gave to the world the true pathology of pebrine, and what is more, showed how it might be eradicated. Yet, as I shall show further on, the men most interested were very slow to believe the hard, dry facts which had been snatched from the unknown, and, never having studied the case themselves, were more inclined to consider the disease as something mysterious-something altogether beyond man's understanding, and consequently uncontrollable. The most ignorant are always the most skeptical! I might mention several parties who have expressed their opinion that the Phylloxera has no connection with disease or decline in the Vine. To such, I simply say examine for yourselves, before giving an opinion. Others whom I might mention go to the other extreme and assert that it must be the cause of mildew, oidium, etc., and without any good reason put a similar opinion in my mouth. To these last, I say: read aright, do not misconstrue, and by no means jump to conclusions!

varieties as are subject to them here; while a few have occasionally been found on their own varieties. Secondly, I have successfully transferred the leaf-lice on to the roots, while M. V. Signoret has succeeded in obtaining leaf-galls from lice hatched on the roots. Thirdly, the winged form obtained by Dr. Shimer from the galls in this country agrees in its characters with those from the roots. Fourthly, the nodosities on the roots are, as already stated, perfectly analogous to the galls on the leaves, and differ only in just such a manner as one would expect from the difference in the plant tissues a view greatly strengthened by the fact that when the gall-lice are forced, by their excessive numbers, to settle on the tendrils or leaf-stalks, they produce swellings and knots approaching more nearly to those on the roots than to the galls. These facts sufficiently attest the identity of the two types, and we have here another case of an insect possessing two distinct habits. It is also like many others of its family, polymorphic, i. e., it exists in different forms; yet we have to do with but one species.

FURTHER FACTS RESPECTING THE HABITS OF THE ROOT-INHABITING TYPE. The young hatched from the eggs on the roots are absolutely undistinguishable from those hatched in the galls; and the gravid apterous female differs in no respect whatever from the mother gall-louse. There is, however, a different egg-depositing form, which, as it moults, becomes tubercled, and more elongated or pear-shaped, as shown at Figure 129, j. Some of these tubercled individuals remain without wings, while others seem to be destined from the first to acquire wings. The young, after attaching themselves, become in a measure stationary, and remind one very much of young bark-lice. The fine hair-like setæ, which in their functions and elasticity are analogous to our tongue, become loosened from the more fleshy rostrum or sheath, as shown at Figure 129, j, and are often so firmly inserted into the root that the louse, if disturbed from its place, generally hangs by them. Three of the threads of this tongue are sufficiently conspicuous, but there should be from analogy, four. The females on the roots seem to be less prolific than those in the galls, and their eggs if anything are rather larger. These eggs are always of a bright yellow color, and, on the dark root, are detected with the naked eye as readily as the lice, which become darker or of a dull orange as they grow older.

The insect is found on the roots in all stages during the summer