Name for two dangerous vine diseases caused by fungi. They originate from North America and were only introduced into Europe in the second half of the 19th century with contaminated vine material. Both fungal species are biotrophic parasites, which means that they feed on 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 mildew fungi, e.g. for apples, peas, cucumbers, roses, spinach and vines. The fungi are strictly host-specific, meaning that they can live exclusively on their host.
Both are conventionally combated with sulphur (powdery mildew) and copper sulphate or Bordeaux broth (downy mildew). Increasingly, however, special fungicides or plant strengthening agents are also being used. Control must often be carried out several times during the growing season. When crossing new breeds, importance is nowadays also attached to resistance to both types of fungi. It should be noted that some species of ladybird, which are among the most important beneficial insects in viticulture, feed exclusively on mildew. However, this is of no importance when it comes to control in the vineyard.