Mildew: Vine Disease
The most notorious form of this vine disease is Oidium Tuckerii, so called because it was a Mr Tucker, gardener to a gentleman at Margate, who discovered it in the vine house in 1845. The disease, usually referred to as ‘Powdery Mildew’, probably came to Europe from the U.S. It could have been carried with imported ornamental plants, such as Virginia creeper or vines, as it is found on these plants in the U.S. And Japan, although native American grapes appear to have some resistance to it. The mildew attacks leaves, stems and fruit, which fail to grow and eventually die and fall off. By 1852 all the vineyards of Europe and North Africa were trying to deal with this apparently mortal threat to the wine business, although the mildew did not actually kill the vine. However its spores were dispersed by wind and rain, so that it was extremely difficult to combat. Fortunately, it was found that dusting with sulphur would check the mildew and protect the vines, because, by increasing the soil acidity, the sulphur somewhat disinfected the vineyard as well as the plants. Today this treatment is routine in virtually all vineyards and winegrowers who cannot get sulphur – as occurred during World War II in many instances – have serious difficulties.
The great authority on vine diseases, George Ordish, calls the Oidium plague a rehearsal for the subsequent appalling disaster of the Phylloxera. He also makes the interesting point that many of the domestic vines which were trained on trellises and over porches and walls in the country houses of Britain – either for table grapes or, even at that stage of the 19th century, for winemaking – would have survived if they had ben treated with sulphur. He thinks that it was the failure of such vines, due to mildew, that created the notion that vines cannot be grown even in the south of England – as they are now.