Term (pará = next to, sitos = fattened) for many types of insects, as well as bacteria, fungi and viruses, which use various other insects or plants as hosts, live on them or obtain nutrients from them. Parasites are highly specialized organisms. Their habitat is usually limited to a few host species, often there is only one host species. In viticulture, parasites are mainly insects that use other insects or their larvae as hosts, eliminate them or at least inhibit their development and are thus generally considered beneficial.
Strictly speaking, however, a distinction must be made between parasites - which develop on or in a host, whereby the host is usually not killed - and parasitoids - which develop on or in a host, whereby they only need one host for their development and the host dies in the process. Parasitoids include ichneumon flies, for example. Among fungi, the biotrophic species (feed on living cells of the host), downy and powdery mildew and the necrotrophic species (kill the host tissue before they receive nutrients from it), Botrytis cinera, are among the parasites. See also under vine enemies.