ON DISEASES OF THE GRAPE. 4351 
OAK AND GRAPE FUNGI. 
Some fifteen years ago I presented to the Academy an account, with microscopic drawings, of two of [eexv } 
the most destructive fungi of our grape-vines. One of them is the “ Mildew,” a downy white coating on the 
under side of the leaves, the peduncles of the just-forming fruit, and the very young berries themselves, causing the 
leaves to wither and the young fruit to shrivel and fall off. That fungus was classed as Botrytis, and is now known 
as one of the Peronospore, another one of which constitutes the potato disease. This appears at the time of flowering 
or soon afterwards. 
The second, and I believe, more common and destructive fungus, attacks the full-grown, yet green berries, and 
destroys them. After penetrating the tissue with its mycelium, it appears on the surface of the berry as a minute dis- 
colored spot, always on the side, which enlarges, and produces black pustules visible to the naked eye, which at last 
kill the berry and cause it to dry up, emitting at the same time their millions of spores. This fungus, described as 
Phoma viticola, makes its appearance in the latter part of July and in August. 
T exhibit to you to-day another grape fungus, which is new to me, and seems to have been unknown to those 
grape growers with whom I have conversed, A yellowish-brown spot, a few lines in diameter, appears on the leaf, 
on the upper side of which a good eye, or a glass, will discover a number of very minute black specks. These are 
little globules, 0.13-0.15 line in diameter, which have a little opening at the top from which they emit their micro- 
scopical spores by the thousand, These oblong or oval spores are one-celled, and have a diameter of 0.013 or 0.014 
line. 
This fungus belongs to the family of Coniomycetes, and to that group which live on decaying vegetable matter. 
These yellow spots are the decaying substance, but their vitality has been destroyed by the mycelium of the fangus ; 
those still more minute threads which penetrate the tissue in every direction, exhaust and kill it, and thus form what 
we may call their fruit, the perithecia, which when mature emit the spores. It belongs to the genus Depazea, of 
which many species, mostly leaf-inhabiting, are described, and it may be called Depazea Labrusce — Grape-leaf 
spot, 
This parasite makes its appearance earlier than the others mentioned above, viz., just before and during [ecxvi] 
the flowering period, and attacks, as far as known, only the leaves, which, where abundant, it kills, and thus 
cripples the plant; it is also found, though rarely, on petioles and peduncles. Dr. Wislizenus informs me that it 
attacks indiscriminately all grape varieties, but more the lower leaves of a stock than the upper ones ; while he finds 
the phylloxera galls on the uppermost not yet full-grown foliage.* 
It is necessary to remind you, that though we know a great many forms of fungi, we know the life history of 
only a very few. It is certain of some, and very probable of many, that they constitute transition states of other more 
highly developed fungi, and only when we shall have become acquainted with the different phases of their develop- 
ment, shall we be able to appreciate their importance and counteract, perhaps, their destructive action. —1. ¢, vol. iii. 
1878, (Read 1876), 
From THe Busuperc CATALOGUE, 3d ed., St. Lovis, 1883. 
The diseases of the grape-vines are principally occasioned by animal or vegetable parasites. I leave [47 (15)] 
others, who are more conversant with the subject, to treat of the former, and will merely state here that our 
species have all grown up with the phylloxera, and would have long ago been extinguished, or rather never could have 
lived, if that insect had such power over them ; but they as well as the insect live on, the latter having no other nourish- 
ment than the grape-vines and their roots : you may call it an accommodation between them: | 
More important for us in America are the fungus diseases, which do our grap ops m 
phylloxera. It is said that in Europe they have discovered over 200 kinds of fungi which live on the different [48 (15)] 
parts of vines, but fortunately only a few of them are really injurious. These are, above all, the mildew of 
the leaves and the black rot of the berries. In Europe they have, besides our mildew, which has lately been introduced, 
the Oidiwm and the Anthracnose. 
The Mildew, Peronospora viticola, appears in frost-like white spots on the under side of the leaves, hairy as ee 
as glabrous ones, here in Missouri generally from the beginning of June, fostered by the sultry and damp or wet weather 
usual at that season ; in the Easter States it seems to come on later in summer and in the fall. Though most common 
on the leaves, it sometimes also infests the petioles of the leaves, the stems of the bunches, and the very young berries. 
But, even if it does not attack the latter, the effect on the leaves alone, which turn brown in spots and are demnert: 
partially or completely killed, destroys the fruit, the berries shrivelling from the base, turning light brown without falling 
off. This is here sometimes termed Brown Rot. 
4h 4h 
* Two paragraphs, referring to Septoria Querci, are omitted here, but will be found on p. 410. — Eps. 
