Microscopically smallest, extremely pathogenic particles (lat. Virus = mucus, juice, poison), which are among the most dangerous enemies of the vine counting. Simple viruses usually consist of a protein coat and nucleic acid enclosed in it (as opposed to the proteinless ones) viroids ). All viruses contain the program (some viruses also other auxiliary components) for their multiplication and spreading. They do not consist of a cell and therefore have no independent replication nor their own metabolism and are therefore on the metabolism of a host cell such as a bacterium reliant.
According to common doctrine viruses are not to be expected to the living beings, but you can at least consider them as "close to life". So far, 3,000 different species have been identified, but there are probably many more. They are viable only on the living tissue of a host and work around its metabolism. The content of the host cell is completely dissolved and degenerated into a malignant cell.
Depending on the nature of the host cells, a distinction is made between plant or fungus viruses that multiply almost exclusively in plant cells, bacterial viruses (bacteriophages) that rely on living bacterial cells, and animal viruses (animal viruses, which include humans). It can affect all parts of the vine and lead to diverse degenerative changes. The symptoms or effects are feebleness or dwarfism, leaf mosaic diseases, double knots, seedless Grapes and many other abnormalities. Viruses can also mutate and thereby change, even crossings are possible.
The transmission of viruses is among other things by nematodes (Roundworms) or insects such as the Rebenschmierlaus, Of the infected vines then spread at one vegetative propagation or at one finishing the viruses out. So far, around 40 types of viruses have been specified that can attack the vine. This triggered vine diseases are, for example Leaf roll disease. Legno Riccio. brushwood disease and various wood diseases (see under Rugose Wood Complex ). For all this can lead to the complete destruction of vineyards, which then have to be cleared.
The danger is so great because the viruses in root remains often continue to live for years. That's why you have to go between the vineyard clear and let new plants lie fallow, in order to withdraw also the nematodes the basis of life. Viruses are preventively also by special pesticides (Viruzide) fights. When refining is used today in principle virus-resistant documents, The infestation of a vine by certain viruses can be caused by the so-called Indexing be determined. Viruses are among others with the thermotherapy fought. There are several ways to detect viral infestation of vines. These include, for example ELISA. Indexing and PCR, See also below Vine enemies,