Vine diseases and pests in viticulture
Vine diseases as well as pests affect the yield of the vine as well as its growth. Vine diseases are all damage to the vine caused by fungal, virus or bacterial attack. However, diseases that are caused by a lack of nutrients can also be counted in the "vine diseases" category.
Combating such damage is a major problem in viticulture . The winemaker can use fungicides against infections caused by fungi , while he is usually powerless in the event of an attack by bacteria and viruses. In the worst case, parts of the vine or even the entire vine die.
Overview of vine diseases
| Diseases | Infection and clinical picture |
|---|---|
| Vine peronospora | At the beginning infection of the vine leaves via fungal spores from the soil,
humid and warm weather conditions promote the spread of the fungus, First sign: oil stains, a circular lightening of infected leaf areas, Later a typical mushroom lawn on the underside of the leaf, Strong downy mildew infestation of the vine |
| Gray mold | High risk of infection in damp weather conditions,
if berries and grape stalks are colonized, the grapes fall off before the harvest, if grapes that are ready for harvest are infested, the desired noble rot is obtained ; such grapes can be used to produce highly noble qualities such as Auslese |
| Powdery mildew | All green parts of the vine can be attacked
the disease can most clearly be deduced from the berry infestation, the majority of the berries are covered with a white-gray mushroom coating, comparable to flour, hot days and cool nights encourage the fungus to spread, |
| Black spot disease | Occurs especially in winter, the time of pruning ,
Symptoms are clear bleaching, lanceolate longitudinal cracks, scabbing, large number of microscopic spore containers, the disease spreads slowly as the spores are spread via drops of water |
| Red burner | Recognizable by the red-brown colored leaf margins, which are mostly already partly dead,
yellow to green areas towards the inside of the leaves make the vine look like burned |
| Eutypiosis | Is caused by harmful fungus,
affects not only vines, but also apricots and currants, leads to the death of the vine, Symptoms are small leaves and broom growth |
| Esca disease | Mainly affects older vineyards,
typical leaf symptoms are death of the leaf |
| Mushrooms on the vine root | The root mold pathogen causes signs of decline and death on the vine,
colonize old and young roots, occur as typical fan-like mycelial plaques and as small fruiting bodies on the root or under the root bark, an unfavorable location, e.g. Waterlogging increases the risk of the disease |
Viruses
Virus infection of the vine roots can greatly reduce the yield. These viruses are transmitted from one plant to the other by roundworms ( nematodes) . This virus complex is combated by using only healthy plants, similar to a tree nursery , and by leaving the vineyard fallow between clearing and replanting. It is important to ensure that as many roots as possible are removed in order to deprive the nematodes of their livelihood and allow them to starve. Because the treatment of the soil with nematode-killing agents ( nematicides ) is harmful to the environment, this measure is in some countries, e.g. B. Germany, prohibited and in other countries, such as France, only used in a controlled manner.
bacteria
The two major vine diseases in viticulture are caused by phytoplasms . In the USA , for example, Pierce's Disease causes great damage to the vines, while the golden yellow yellowing occurs primarily in the south of France. Some of the harmful fungi attack the trunk, which can cause the plant to die, while others damage the green parts of the vine, such as the leaves, shoot and grapes.
The first groups include the diseases Esca and Eutypa.
Mushrooms
Fungi usually attack the roots of the vine. When disposing of them, you have to burn all dead vines, otherwise they pose a new risk of infection. In order to prevent fungal infestation, the winemakers have to cut the vine in such a way that no large wounds occur, as these would otherwise provide a gateway for fungi.
Widespread fungal diseases in viticulture are downy mildew ( downy mildew ), powdery mildew (Oidium) and gray mold (botrytis).
Downy mildew mainly attacks the leaves, so that the leaves of the grapevine are thrown off prematurely. This particularly affects photosynthesis and limits the fructose concentration in the grape. Furthermore, the composition of the reserve substances in the rootstock is changed. Downy mildew is combated with preparations made from copper oxychloride.
Powdery mildew can colonize foliage and grapes, cause harvest losses and also reduce quality. Not all grape varieties behave the same way towards this mushroom. Some, like carignan , are very susceptible to the fungus. Others, like Syrah or Pinot noir , are less so. Once they are infected, it is very difficult to fight the fungus. The ideal solution is essentially the use of sulfur-containing preparations.
There are three groups of organic substances used to combat fungus: Products that only protect the organs on which they are located through contact (contact fungicides); Products that can penetrate the treated organs and stop an attack from inside the plant (locosystemic agents); and those that spread almost throughout the vine (fully systemic means).
The gray mold affects the quality and also the quantity of the harvest. The best method of control consists in preventive measures that promote the vitality of the vine and ensure good ventilation of the foliage wall. In addition to reducing the nitrogen supply via the soil, this requires airy, spacious training and simultaneous foliage work (removal of the second tendril, thinning of the leaves).
Pests
Among the pests, the two grape moth species, the single-leaf grape moth ( Eupoecilia ambiguella ) and the crossed grape moth ( Lobesia botrana ), are particularly important. They form two to three generations in one summer and in their different larval stages damage the buds, the flowers and the ripening berries.
The means of control must be selected according to the stage of development of the grape moth and used at the right time. The less harmful the products are for the environment, the more precisely an optimal control date must be determined.
Overview pests in the vineyard
- Grape moth in its developmental stages
- Vine leafhoppers
- Rhomb tensioner
- Vine weevil
- Phylloxera
Individual evidence
- ^ A b c d Eckhard Supp, Hartwig Holst, Helene Jaeger, Paul Aston: Wine . HFUllmann Publishing, Potsdam 2008, ISBN 978-3-8480-1143-8 .