Mildew On Grapes (22 Photos): How To Treat The Disease? Preparations For The Treatment Of Downy Mildew, Other Methods Of Struggle

2024 Author: Beatrice Philips | [email protected]. Last modified: 2024-01-09 13:15

Mildew is a common disease that often occurs in vineyards. We will tell you about how it looks and how to treat it in the article.

Description of the disease

Mildew is one of the fungal diseases that can often be observed in most grape varieties .… This disease is also called downy mildew, mold or rust. The causative agent of this disease is the fungus plasmapar vitikola. It was first discovered in North America in the 19th century. At the end of the century, the disease made itself felt in European territories. Until the 20th century, this infection could destroy most of the grapes, which lasted until chemicals were invented to combat it, after which gardeners were able to fight the virus themselves.

Mildew has several stages of development, and each stage has its own characteristics .… First stage - mycelium … She is the first, at this time the spread of the fungus occurs. Fruit corpuscles increase due to the high level of moisture, after which they burst, and then they are carried by the wind. The second stage is called conidial … During this period, the spores of the fungus enter the planting and, having settled there, begin to develop gradually. This phase takes place quite quickly, most often it ends before the moment when the grapes begin to bear fruit, and its fruits ripen. Next comes marsupial stage. It will be difficult not to notice her. At this stage of the development of a fungal infection, the foliage that has been affected by the virus becomes covered with a noticeable bloom and yellowish spots. Further, on the same sheets, fruiting bodies begin to form, in which there are spores, which occurs somewhere in July or August. At the end of summer, they move to healthy seedlings.

Mildew infects almost the entire plant, bypassing only the root system. This is a harmful and tenacious infection, the causative agent of which easily tolerates both high temperatures and frost. Often he stays in the ground or on fallen leaves for the winter, where he spends the winter. Its life span is from 2 to 5 years.

In one season alone, it can produce about 20 generations of spores, which are capable of traveling up to 100 kilometers.

Causes and signs of defeat

First of all, let's talk about the causes of the defeat of grapes with such a fungal disease as mildew. The main reason is most often an improperly organized vineyard . So, the disease can occur in cases where the place for planting grapes is chosen incorrectly and is too shaded. Another reason is the thickening of the landings, which interferes with normal air circulation. The lack of a normal distance between grape bushes leads to an excessive planting density and a lack of ventilation, which subsequently entails the development of fungal diseases.

The cause of the disease can also be an incorrectly selected grape variety that does not have strong immunity and is very susceptible to this kind of disease … This also includes the use of weak planting material, which in the future is unlikely to be able to resist the fungus. Lack of regular and high-quality care can also lead to the appearance and spread of fungal infection. Good care means thinning the plant, carrying out autumn pruning and other measures to form a bush, as well as observing preventive measures, getting rid of weeds and the remnants of old foliage. If all this is absent, then the disease will not keep itself waiting long.

Top dressing is another reason for the disease affecting the vineyard … And here we mean not only a deficiency of any useful microelements, but also their excess. For example, the cause of the appearance of mildew can be too much nitrogen in the soil, as well as a lack of potassium and other substances necessary for the plant. Weather conditions also have an impact on the emergence and further spread of the disease. A high level of humidity and warmth ranging from +8 to +30 degrees - it is in such conditions that the fungus begins to develop. Drought and temperatures of +30 degrees and above, on the contrary, inhibit the spread of fungal disease.

Now let's talk about the signs of being affected by the disease. The first thing to look out for is the presence of plaque on the leaves, which has a thickness of 1 millimeter . Usually it covers the entire leaf plate of a plant that is sick. With the development of the disease, yellow spots form on the foliage, subsequently the leaves simply wither and fall off. On the berries themselves, you can also notice spots. At first they are light, and then they change color to a darker one. The taste of the berries also deteriorates markedly, the taste becomes bitter . The number of berries is also decreasing. The level of fruiting with this disease can decrease by 60% or more.

Drugs

Drugs

Chemicals are most effective in the fight against various infectious diseases, using them is the best solution, especially when it comes to advanced cases . Despite being effective and fast-acting, chemicals also have significant drawbacks. They are quite toxic, and therefore, if used incorrectly, can harm both the plant and the person himself. In addition, the first treatment for the disease must be carried out before the flowering of the plant. During the collection of juice with grapes and its intensive growth, it is impossible to spray the plant with fungicides.

So, for the treatment of grapes against mildew and its treatment, the most commonly used agents such as Fitosporin, Hom, Baikal, Consento, Topaz, Profit Gold . Spraying with these drugs must be strictly according to the instructions, observing their dosage. In this case, you must observe safety precautions and use protective equipment, including a respirator, goggles, rubber gloves and a protective mask.

It is advisable to process the plant in calm and dry weather, while the interval before watering the planting should be at least an hour - so you reduce the likelihood of the plant getting burns. To see the best effect of these drugs, it is recommended to alternate between them.

It is allowed to process a vineyard with this kind of means no more than 5 times during the whole season.

Folk remedies

Folk remedies are also very popular with summer residents. They are easy to use, completely harmless to humans and quite economical, you can make them yourself at home . However, it should be borne in mind that in those cases when the disease is started, the most effective control measures are urgently needed, folk remedies will not work here . A plant can be treated with such solutions either for preventive purposes, or in order to eliminate a fungal disease in the early stages of its development and spread.

Now let's talk about the recipes themselves. So, for one of the solutions, you can use ordinary soda and potassium permanganate . The method for preparing the mixture is simple. You will need 5-6 grams of potassium permanganate, 60-70 grams of baking soda, and 10 liters of water. All this needs to be mixed well, after which the plantings can be sprayed. Suitable for combating disease and tincture based on onion peel . You will need a container that you need to fill halfway with the main component, and fill the remaining space with water. All this needs to be boiled for about half an hour, then leave to infuse for a day. After this time, add a tablespoon of honey to the solution, mix it and strain. After that, it can be used on plants.

Another effective remedy in the fight against fungal disease Is a tincture based on garlic . You will need 200 grams of the main component, which must be crushed and filled with a liter of water. All this should be infused for a day, after which 2 large tablespoons of salt, 50 grams of grated soap and 5 grams of potassium permanganate must be added to the mixture.

The mixture must be thoroughly mixed and added to it so much water that the volume of the solution is 10 liters.

You can also do solution using iodine, baking soda and potassium permanganate . To prepare such a product, you will need 5 tablespoons of baking soda, 10 liters of water, 20-30 drops of iodine, depending on the degree of infection and 5-6 grams of potassium permanganate. In order for a protective film to form on the plant after processing, another 50 milliliters of liquid soap must be added to the solution, after which it must be mixed well and used for processing.

Another good mortar component is this is wood ash … It is effective not only as a plant food, but also in the fight against a variety of fungal diseases and harmful insects. For the solution, you need 350 grams of the main component, which you need to pour boiling water, all this must be mixed well and given several hours for tincture. For the thickness of the liquid, you can drop 70-80 milliliters of soap there. Further, you can carry out processing, it is desirable to do this either in the evening or in the morning with an interval of 30-40 days.

In addition, many summer residents recommend plant dill near grapes … This plant can not only prevent the appearance of this fungal disease, but also scare off many parasitic insects with the help of its smell. You need to plant it at a distance of 30-50 centimeters from your vineyard.

Agricultural techniques

Agrotechnical methods are more of a preventive nature . Their systemic use will help reduce the risk of the onset and spread of the disease to a minimum. So, first of all, the plants need to be placed in those areas that are well illuminated by the sun. You need to plant grapes like this so that there is a certain distance between its bushes, which will ensure normal air circulation.

When a disease occurs, it is necessary to immediately eliminate the affected planting areas. It is also necessary to timely carry out the garter, pruning and pinching of the vines. In addition, in order to increase the immunity of a plant and its resistance to various diseases, it must be supplied with nutrients and trace elements, in every possible way avoiding their deficiency or excess.

Particular attention should be paid to feeding with a high content of phosphorus and potassium.

Prevention measures

Compliance with preventive measures will help ensure that your plant is fully protected from mildew and other diseases . So, initially it is necessary to regularly check the vineyard for the presence of symptoms of a particular disease. When found, the affected areas must be immediately eliminated and burned, and the healthy part must be carefully processed.

After the final harvest, you need to get rid of all plant residues, since a virus could remain on them, which, over time, is able to move to healthy areas of the grapes. Before wintering, the planting must be treated with iron sulfate for prevention. In summer, especially in hot weather from +8 to +30 degrees, you need to carefully monitor the watering of the plant. In no case should excess water be allowed, since heat and high humidity levels are the most favorable conditions for the development of fungal diseases. At the same time, during watering, water should not be allowed to enter the grape foliage and shoots, otherwise there is a risk of the plant getting a burn.

A healthy seed variant must be used for planting grapes .… It is also recommended to take a closer look at those plant varieties that are highly resistant to various diseases, including mildew. This will not be able to protect your vineyard 100%, but with good care and preventive measures, it will significantly reduce the likelihood of disease.

In addition, you need to get rid of weeds and harmful insects, which are often carriers of various diseases, on a regular basis.

Resistant varieties

Unfortunately, there are no grape varieties that are 100% resistant to diseases like mildew. However, there are those who are able to resist the disease. So, the most resistant are such grape varieties as " Vitis riparia", "Cleret Bulbasa", "December", "Arched ". I have average resistance such varieties as Bianca, Moldova, Victoria, Augustin, Timur, Arcadia, Talisman, Laura, Danko, Rusmol, Viorica, Muromets and Riesling Magarach ".