48 Mildew. 



BUSHBERG CATALOGUE. 



Eot. 



covered over 200 kinds of fungi which live on the differ- 

 ent 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 

 besides our mildew, which has lately been introduced, 

 they have the Oidium and the Anthracnose. 



The Mildew, Peronospora viticola, appears in frost- 

 'like white spots on the under side of leaves, hairy as 

 well as glabrous ones, and may generally be observed 

 here in Missouri from the beginning of June, fostered 

 by the sultry and damp or wet weather, usual at that 

 season ; in the Eastern 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 eventually partially or completely killed, de- 

 stroys the fruit, the berries shrivelling from the base, 

 turning light brown without falling off. This is here 

 sometimes termed " brown rot." 



The fungus at first pervades the cellular tissue of the 

 leaf | then, a few days later, the minute fungus stems 

 protrude through the stomats (breathing pores) of the 

 lower surface, forming little upright branching plant- 

 lets, which might be compared to a miniature spruce 

 tree, singly not visible to the naked eye ; at the end of 

 the branch-lets they bear the summer spores (conidia), 

 w r hich mature, are discharged, spread by wind or other- 

 wise, and, when moistened, germinate with astonishing 

 rapidity. Late in the season the fungus produces what 

 are called the resting spores (oospores) in the interior 

 of the leaf-tissues, and, while the others propagate the 

 parasite in summer, these larger and more enduring 

 ones keep alive through winter and insure its growth * 

 in the following summer. Thus it is seen that the dead 

 mildewed leaves, containing the resting spores, really 

 do preserve the.germs for the next season's mildew. 

 These leaves ought to be destroyed by carefully ga- 

 thering and burning them , or by burying them deeply 

 in the ground. The direct destruction of the fungus 

 has been often attempted, and by different means, 

 -especially by sulphur -sprinkling, but without any 

 marked effect ; a dry spell of weather, however, arrests 

 it most effectually for the time being. 



The Peronospora has since 1878 made its appearance 

 in Europe like the Phylloxera, accidentally intro- 

 duced from this country and has added another terri- 

 ble infliction on the wine-growers there, threatening 

 to be worse than the Oidium, which years ago \ised to 

 decimate the grape crops of Europe. 



A few words about this O'idium may be in place 

 here. This is a mildew-like fungus which appears on 

 the outside of the upper surface of the vine-leaves, and 

 bears its fewer spores on smaller, not much branched, 

 stemlets ; it destroys the vitality of the leaves, and 

 with it the crop, just as our mildew does. Its resting 

 spores are unknown and with its life-history we are 

 not so well acquainted, but we know that sulphur 

 sprinkled over the leaves will destroy it. It made its 

 first appearance, as far as it is known, about 1845, in 

 graperies at Margate, near London, and spread rapidly 

 and destructively over a great part of Europe and 

 the islands, especially Madeira, where grape culture 

 was almost annihilated by it ; but it seems now to be 

 less common or less injurious than it was years ago, 



and may possibly have run its course, just as other epi- 

 demics are apt to do. It is unknown where it origi- 

 nally came from ; some suppose that it originated in 

 America, but it has never appeared here in the form 

 under which it is known in Europe ; whether in 

 another form, is still questionable among our best 

 mycologists ; at all events we have thus far only one 

 destructive form of mildew here, the Peronospora. 



The second great fungus pest of our vineyards is the 

 Black Rot, Phoma uvicola. On the berries, but never 

 on the leaves or stems, generally about the time that 

 they are full grown, in July or August, very rarely on 

 half-grown berries in June, a light brown spot with a 

 darker central point is observed on the side and not 

 near the stem ; this spot spreads, and darker, shining 

 nodules or pustules, plainly visible with the naked 

 eye, begin to protrude above the epidermis ; at last the 

 whole berry shrivels up, turns bluish-black, the pus- 

 tules roughen the surface, and each one opening at 

 its top emits a whitish worm-like thread, which con- 

 sists of innumerable spores glued together with a mu- 

 cilaginous coating. In this condition the spores are 

 inert, but rain will dissolve the mucilage and liberate 

 and wash down the spores, or they will fall to the 

 ground with the dead berries. What then becomes of 

 them, whether they enter the soil, or how they propa- 

 gate the fungus, is as yet unknown. At all events it 

 seems advisable to gather all the affected berries, if 

 such a thing can be done, and destroy them. 



In Europe they have another fungus disease of the 

 grape, called in Germany Brenner, in France Anthrac- 

 nose, and described under the name of Sphaceloma am- 

 pelinum, which by some authorities has been supposed 

 to be another form of development of our Black Rot, 

 above described ; this, however, seems very doubtful. 

 We have, as it seems, never had the Sphaceloma,* nor 

 they the Phoma. The former attacks all the green 

 parts, leaves, young stems, or green berries, and forms 

 open wounds which might be compared to ulcers ; 

 while our Phoma is restricted, as far as known, only to 

 green berries, without breaking up the tissues or form- 

 ing ulcers. The Sphaceloma seems to be an old disease 

 in Europe, already known in the last century. Mycol- 

 ogists are now carefully studying these questions. 



Had we known that we would be favored with the 

 above article on the Diseases of the Grape-vine by so 

 great an authority as Dr. Engelmann, we would have 

 omitted some of the following lines, previously written 

 by ourselves, in preparing this new edition of our Cata- 

 logue. This circumstance and the importance of the 

 subject will excuse what may seem a repetition ; and 

 while the preceding will stand as the description of 

 the fungus diseases by the scholar, the following may 

 not be unwelcome as the practical grape-growers' 



* Unfortunately we have of late, also, the Sphaceloma 

 in our vineyards. How or whence it c.ime, we do not 

 know; but, having observed the Anthracnoxe iti Prance, 

 we could not help recognizing the same here; for- 

 tunately, so far, to no serious extent. 



