Name for two dangerous vine diseases caused by fungi. They originate from North America and were only introduced to Europe in the second half of the 19th century with contaminated vine material. Both types of fungi are biotrophic parasites, which means that they feed on the living cells of the infected host. The two powdery mildew diseases are often confused, not so much because of the disease symptoms, which are quite clear, but because of the confusingly similar names. There are plant-specific powdery mildew fungi, e.g. for apples, peas, cucumbers, roses, spinach and vines. The fungi are strictly host-specific, i.e. they can only live on their host.
Both are conventionally controlled with sulphur (powdery mildew) and copper sulphate or Bordeaux broth (downy mildew). Increasingly, however, special fungicides or plant strengtheners are also being used. Control must often be carried out several times during the growing season. When crossing new varieties, resistance to both types of fungus is nowadays also emphasised. It should be noted that some species of ladybird, which are among the most important beneficial insects in viticulture, feed exclusively on powdery mildew. However, this is of no significance in vineyard control.