A Few More Words on the Grapevine Disease

A few more words on the grapevine disease.

(Contributed.)

Permit a practical farmer to present to your readers in the following lines his views, gained through personal observation, on this subject that has recently been discussed so frequently, especially in public newspapers, yet remains far from exhausted.

For a couple of years already, the grapevine disease had made itself felt in Italy, even in northern Italy, through devastations that took on greater extent especially during the wet summer of last year.

In Tyrol, only in the past year were individual vines seen to be affected here and there, most frequently in the vicinity of Meran, without significant damage having yet resulted.

All the more violent was the outbreak of this disease this year. The well-known parasitic plant — Oidium Tuckeri — already covered the leaves of the vine at blossom time, and in rapid progression also enveloped the developing berries, whose growth, hindered thereby, lagged behind and ceased completely. The berries that remained so small, like the few not seized by the disease, were no longer capable of absorbing the juices pressing forward from the vine. The widespread bursting — the second manifestation of the disease —, favored by the extremely wet and warm weather of this year's summer and autumn, was alongside the drying up of the berries the necessary consequence, and the general failure of the vintage the sad conclusion of the disease.

These manifestations of the disease showed themselves most devastatingly in Bozen and in Gries, to a far lesser degree in the lower Adige Valley, in Kaltern and its environs, and almost not at all on the slopes sheltered from the south wind.

To these observations must further be added that throughout the entire spring of this year, the south wind was almost uninterruptedly prevalent in our region.

Supported by these perceptions, one would hardly go astray in asserting that the light seed of the Oidium, imperceptible to the naked eye, was blown in quantity from the south into Tyrol, adhering to the vines on the slopes swept by the wind, flying over lower-lying areas, not reaching the locations unmastered by the south wind at all, and finally settling in greatest abundance where — as is precisely the case in Bozen — considerable mountains on the northern side placed an insurmountable wall against further flight. Might this not explain why precisely in Bozen not only no vines or extremely few were spared by the disease, but also vegetable plants, grass, and even trees were so frequently found covered with the mentioned parasitic plant?

The writer of this considers himself convinced that the grapevine disease was brought into Tyrol solely in this manner, and therefore did not originate in Tyrol.

But if it is not native to this country, as the cited observations demonstrate, its persistence should also not be feared, unless climatic conditions similar to this year's particularly favor its spread from the countries where it originated and is indigenous.

The propagation of the disease merely through the seed formed upon our grapes and vines is scarcely conceivable, considering that the seed produced on and in the grapes must necessarily be deprived of all germinative power by the fermentation process, by brandy distilling, and by other uses thereof, while that adhering to the leaves is neutralized by the consumption of the leaves as cattle fodder. The complete destruction of the infected parts may for this reason not be indispensable; at most, simply washing the vines with lime water may be advisable as a precaution to destroy any seed remaining upon them.

The wine obtained from the diseased grapes has been found harmless to health according to experiences thus far, and, unless already dried and subsequently wetted grapes were used, still promises good quality, as copious sugar formed even in the affected grapes during the persistently warm season, just as the must tasted good and went quickly into fermentation.

The still-green leaves of the vines dusted with mold are readily eaten by cattle and cause them no harm.

On the vines the wood appears well matured and healthy upon cutting through, indicating that the vine itself does not seem to have suffered from the disease.

The author believes he can conclude these reassuring experiences with the remark that he has applied all remedies against the grapevine disease praised hitherto in public newspapers or elsewhere, but has found them all ineffective. Only through prolonged observation and experience might genuine remedies, and especially preventative measures against it, be discovered.

Until then, consolation must be taken from the fact that only the unusual climatic conditions of last year, as of this year, caused the extraordinary development of the Oidium and made the plants receptive to it; according to which it is hardly to be doubted that as soon as these conditions change and regular, but especially drier years return, the affliction will disappear just as quickly as it arose.