Instructions for the use of fungicides for grapes
Growing grapes is not easy, because it often suffers from fungal diseases. It is because of them that the quantity and quality of the harvested berries are reduced. To combat the fungus, fungicides are designed - drugs specially developed by scientists. These chemical mixtures have a dual effect: not only kill pathogens, but also prevent infection of plants - leaves and vines, thus preserving the crop.
In the article, we will try to figure out how to properly apply fungicides so as not to harm the grapes, while getting rid of the fungus. The most popular brands of fungicides with their brief characteristics will also be listed.
Kinds
Grapes can be affected by spores of various fungal diseases: mildew, oidium, gray rot (as well as black and white), black spot. If you notice them in a timely manner, then it is quite easy to heal the plant without losing the quality and quantity of fruits. In advanced cases, you can completely lose the crop and even grape bushes. Fungicides are used to protect plants or prevent fungal infection. They may be organic or inorganic.
The name "fungicide" comes from two Latin words - "fungus", which means "mushroom", and "caedo" which means "I kill". These compounds are just designed to destroy fungal spores on plants, including grape shoots. They process bushes, shoots and leaves.
Fungicides are very popular with beginners and experienced growers, as they are very effective both for treating plants from a fungus and for preventing this kind of disease. At the same time, they have a relatively low cost and low consumption per 1 square meter. Another plus: you do not need to calculate the dosage, as it is detailed on the packaging of the drug, in the instructions. The funds are stored for a long time, so they can be used for two seasons.
Fungicides are of two types of action: local or systemic. The former do not penetrate the plant cells, remaining on the surface. Local chemicals prevent the germination of the fungus, spores are killed by coming into contact with the substances in the fungicide. As for systemic drugs, they act in a complex way - both on the surface of the bush and circulating through its cells. Accordingly, the treatment goes in the same way: outside and inside.
According to the main property, fungicides can be divided into two large groups.
- Therapeutic. They can and should be used both before the disease - for preventive purposes, and after - to heal the plants.
- Protective. They need to be sprayed with grape bushes at regular intervals to prevent fungal infection.
According to the principles of their action, herbicides are of different types.
Contact
They do not have the ability to penetrate into plant parts, remaining on the surface. The drugs do not protect against all types of fungus - only from those that have not yet sprouted, and prevent its further spread. It is important to consider that the contact fungicide is easy to wash off the plant - with rain or water when watering. Therefore, when applying it, you need to ensure that the bush is completely covered, and after precipitation falls, renew the coating. The inner surface of the leaves must also be coated with the compound.
Only in this way can high-quality protection of grapes from fungus be carried out. These chemicals include Bordeaux liquid, Omal, Rowright.
Systemic
These preparations differ from contact ones in that they are able to penetrate into the plant. Their circulation is carried out in cells. It is systemic herbicides that help fight the disease from within the plant. You also need to use them regularly, with an equal period of time. They cannot be washed off the plant by rain or water. The optimal time to apply systemic fungicides is before and after flowering. But if the first signs of the fungus appeared earlier, then the grapes should be immediately processed. Systemic fungicides are "Kvadris", "Topaz", "Strobi".
Combined
As the name suggests, these preparations combine the properties of systemic and contact preparations. The group includes such herbicides as "Shavit", "Cabrio Top".
The composition of fungicides also differ. Depending on the components, two groups are distinguished.
- Based on copper, these are, for example, Azofos, Profit Gold, Ordan. The drugs included in this group have a universal effect, that is, they are effective against any fungal diseases.
- Azoles. The composition of these drugs includes substances such as imidazole, penconazole and other similar substances. Azolas include Coronet, Tilt, Skor, Raek, Topaz and other analogues. The main diseases against which azoles act are powdery mildew, scab, rust, root rot.
Regardless of which type and brand of fungicide you choose to treat the vineyard - contact or systemic, there must be regularity in its application. It is best to combine both types, then the protection of plants from the fungus will be the strongest.
It is also necessary to alternate the drugs used, since fungal spores tend to get used to pesticides and remain resistant to them.
During the flowering of grape bushes, it is strictly forbidden to spray them with a fungicide.
Popular drugs
When choosing a fungicide with which you plan to treat your vineyard, you should be guided by the reviews of not only experienced gardeners, but also biologists and breeders involved in breeding and caring for new grape varieties. In this section, we will focus on the most popular and effective drugs.
To rid the grape bushes of such misfortunes as powdery mildew, scab, black spot, Ikarus and Topaz chemicals are suitable. These same drugs will help the grapes grow.
Against mildew apply "Polyhom". It is a moderately toxic drug with an unlimited shelf life. Up to 800 ml of solution is consumed per square meter of vineyard. "Mikal" is no less effective not only in the fight against mildew, but also with oidium, black rot.
An organic fungicide such as Polyram is used only for the prevention of fungal diseases. Timely processed bushes are not infected with diseases such as scab, rust, mildew. Its granules are dissolved in water. However, the pesticide also has disadvantages: it is produced only in ten-kilogram bags, which is not very convenient if you have a small vineyard. In addition, already diseased plants will not be cured.Even "Polyram" is easily washed off with water, without penetrating inside the leaves and shoots.
"Falcon" is a pesticide that is popular with gardeners. Its consumption is about 800 liters per hectare. Bushes are treated with this preparation 4 times per season. It helps treat oidium.
Horus is another versatile fungicide. But "Acrobat" is a contact herbicide, it is effective as a prophylactic agent, it is used in the periods between treatments of bushes. Antrakol has a similar property.
Preparations of the "Rescuer" group belong to insect-fungal stimulants, that is, they not only fight fungal spores, but also stimulate the growth of bushes.
Processing scheme
In order to prevent vine bushes should be treated with herbicides annually. The substances that make up fungicides are absolutely harmless to the plant, but poisonous to fungal spores.
To cure a grape bush, you can take a systemic, contact, and combined fungicide. You can make it yourself, or you can buy it in a specialized store.
For example, to prepare a Bordeaux mixture, you need to take 300 g of lime and 300 g of copper sulfate and dilute them in 10 liters of water. This is a moderately toxic mixture, the indicated amount of which is enough for 5-6 treatments of 10 square meters of the vineyard.
To create low-toxic colloidal sulfur, it is enough to add 40 g of sulfur to 10 liters of water. This amount of the mixture will be enough for 3-4 treatments of ten square meters.
The choice of herbicide type depends on the climate zone in which the vineyard grows, as well as the age and physical condition of the bushes.Spraying should be carried out at least 4 times during the growing season (except during flowering): before the buds are formed, during the formation of buds, after flowering, at the beginning of the formation and growth of clusters.
It is best to process bushes in the evening, on days when there is no intense heat and rain. The bush should not be wet. Processing is done from top to bottom.
Depending on the age of the bush, different types of fungicides should be applied. If the shoots are young, it is best to take drugs to combat oidium; at the time when the buds are forming, chemicals with copper will do; when the fruits grow and pour, herbicides with sulfur are most useful.
In the first decade of August, when the fruits ripen, all types of spraying are completed.
Breeding of new varieties of grapes is happening all the time, and this is very good for the wine industry, as it helps to create original varieties of wines. However, selection often entails a decrease in the response of bushes to pesticides. That is why chemists and biologists are forced to constantly develop new drugs, striving to ensure that they do not harm grapes, but at the same time destroy fungal spores.
There are many fungal diseases that vine bushes are susceptible to. The intensity and type of infection depends on the grape variety, its properties. If the variety is resistant to fungal spores, then the spread occurs like a forest fire - it instantly covers the leaves and shoots. If the variety is resistant to parasites, this will not happen, a small focus is easily destroyed when treated with a fungicide.
When the infection has spread widely in a bush or, much worse, in a vineyard, the fight against it will be very difficult.If the moment of spread of the fungus is missed, and most of the bush is affected, it is often impossible to save the plant. Therefore, prevention in this matter is much more important than treatment. Especially if your grape variety is not resistant to fungal diseases.
Both young plants and adults suffer from fungal spores.
First you need to conduct a thorough inspection of the plants, remove all diseased leaves and shoots - only healthy branches should remain on the bush.
For the first spraying (in the spring, before flowering), it is better to take Bordeaux liquid. When preparing it at home, you need to remember that first, 300 g of lime (slaked) is dissolved in one five-liter bucket of water, and 300 g of copper sulfate in the other. After both substances have dissolved, each in its own container, the copper sulfate solution must be slowly and carefully poured into the lime solution. You can’t do the opposite, Bordeaux liquid will not be as effective in combating the fungus.
To check the quality of the liquid, a metal object is immersed in the mixture. If everything worked out as it should, then copper will not settle on the metal.
Bordeaux liquid is poured into a spray bottle and the bushes are sprayed from top to bottom.
Tips
Regardless of whether the toxicity of the fungicide you choose is high or low, personal protective measures must be followed. This kit includes:
- respirator;
- rubber gloves;
- protective suit or overalls;
- goggles or eye mask.
Processing should be done either before sunrise or after it sets. Since liquid droplets have the properties of a lens, the sun's rays, falling on them, can burn the leaves. Clear weather without wind is best for spraying.
Do not violate the dosage indicated in the instructions for use of the fungicide. It is not the same for different drugs, so it is important to study the instructions well before you start preparing the solution and processing the bushes.
No need to limit your vineyard to one type of herbicide. In order to provide good protection against fungus, a minimum of 3 or 4 chemicals is required.
Feedback from experienced growers suggests that the best fungicides are those that combine the properties of both contact and systemic preparations.
For information on how to treat grapes with a fungicide, see the following video.