Powdery mildew is a common disease that affects various plants, including grapes. The disease is also known as “oidium”. Treatment should begin as soon as the first signs of damage appear. The symptoms are quite pronounced. Therefore, gardeners often begin to treat grape oidium in a timely manner. If all recommendations are followed, the therapy is successful and it is possible to save the plants from death.
Description of the disease and causes
Oidium disease affects the foliage and shoots of plants. Powdery mildew of grapes is a fungal disease that develops when favorable conditions are created for it and spreads to the inflorescences, preventing them further development and maturation.
The disease is common in viticulture. It is noted that the fungus does not live on dried leaves and shoots, but lives exclusively on living tissues. In cracks in the bark and on the buds it is located in the form of mycelium, where it safely survives the winter. Spores can persist throughout the season. Pathogenic microorganisms multiply quickly and, after infecting the entire bush, move to a new plant.
Among the factors that provoke the rapid spread of fungal infection are the following:
- sudden climate change;
- removal of stepchildren is carried out irregularly;
- the vine is tied to the trellis.
The fungus is carried by the wind to uninfected plants. Favorable conditions for this are excessive air humidity, dampness and insufficient ventilation of the vineyard area.
External signs
Oidium on grapes manifests itself with a number of characteristic signs. Leaves affected by the fungus look as if they are dusted with flour. Depending on the time of year, the disease can be detected by a number of additional symptoms.
in spring
The onset of the disease is usually observed in May. The following changes are observed:
- some shoots change color to yellow and lag behind in development;
- curling of the sheets is noted;
- plaque appears on the green plates. When it is wiped off the foliage, an unpleasant aroma is felt.
Summer exacerbation
Starting in June, the symptoms of the disease become even more pronounced:
- the foliage on all sides is covered with a coating of light gray shade;
- plaque appears on the inflorescences, and after a while on the bunches;
- the foliage dries up;
- inflorescences and shoots die off;
- small fruits begin to dry out, and larger ones begin to burst;
- A characteristic coating appears on the surface of the berries, and when it is removed, spots with a dark coffee color become visible.
When affected by oidium, the yield is significantly reduced. Ripe berries are unsuitable for consumption even in processed form.
Fighting methods
It is extremely important to take timely measures to combat grape oidium. Only in this case will it be possible to protect the vineyard from destruction. In this case, special chemicals can be used. It is also possible to fight the disease with traditional methods.
The main thing is to strictly follow all the rules for processing plants and perform such manipulations systematically and not periodically.
Chemicals
It is customary to use preparations for oidium long before the fruits ripen. Due to this, significantly fewer harmful substances will be in the berries. After the crop has already been harvested, fungicides are applied.
The following remedies are effective against the disease:
- Speed;
- Byleth;
- Topaz;
- Thiovit-Jet.
Also, in the fight against oidium, it is allowed to use Iskra-Bio and copper chloride. Tank formulations are effective in the therapy process. To prepare them, several types of drugs are mixed in one container:
- 2 ml Topaz;
- 20 g Ridomila Gold;
- 40 drops Ecosil;
- 10 liters of water.
The first treatment of plants with this mixture is carried out even before flowering begins. The second time they are sprayed already at the moment when the fruits begin to gain weight.
Traditional methods
Folk remedies will also help get rid of powdery mildew. The most effective among them are the following:
- Baking soda solution. To prepare the solution, pour 50 grams of powder into 4 liters of water and add liquid soap (a tablespoon) to this mixture. The resulting liquid is sprayed onto disease-affected plants.
- Colloidal sulfur with Bordeaux mixture. The components are taken in equal proportions. The effectiveness of treatment against powdery mildew is significantly reduced by precipitation.
- Copper sulfate . To prepare a solution based on it, 10 grams of powder are diluted in a bucket of water. The remedy for oidium is used until the buds form on the vine.
- Ash. A kilogram of raw materials is diluted in a bucket of warm water and infused for five days, stirring from time to time. Before starting processing, add an additional 30 grams of grated soap to the mixture. This component is needed so that the solution does not drain from the plant, but is fixed on it. The product is considered one of the safest and most effective in the fight against disease and various pests.
- Tansy. To prepare a decoction, you need to pour 300 grams of fresh plant into a bucket of water and leave for 24 hours. After this, the liquid is placed on the stove and boiled for a couple of hours. After the broth has cooled, it is filtered. The composition moistens the soil directly under the bushes.
Prevention measures
In order to prevent the development of the disease, you must adhere to the following recommendations:
- Tie up the vine in a timely manner, break off shoots, pruning and removing weeds. Thanks to this, the vine will be fully ventilated.
- Spray the bushes using an ash solution. Half a bucket of this substance is mixed with seven liters of water and infused throughout the day. Before processing the vineyards, one hundred grams of laundry soap is added to the composition.
- Use a mixture of manure and water. The components are taken in a ratio of 1:3. The mixture is infused for about three days to allow the fermentation process to begin. Before spraying, water is added again to the prepared mass in a ratio of 1:3.
The optimal time for carrying out preventive work is considered to be the early growing season. In total, such manipulations are performed three times.
To avoid the development of the disease, they also resort to the use of sulfur-containing chemicals. Thanks to this element, spores are destroyed. In this case, agents such as Tiovit Jet or Cumulux DF can be used. About forty grams of the drug are consumed per bucket of water. During the season, spraying with its use is carried out up to four times. The interval between procedures is one and a half weeks.
Disease-resistant varieties
Many grape varieties are susceptible to the development of oidium. Most often, plants from which high-quality vintage wine are produced are affected. However, varieties have been developed that are resistant to this disease. Among them:
- Chardonnay;
- Libya;
- Aligote;
- Merlot;
- Kishmish;
- Charlie;
- White miracle;
- Harold;
- Faith.
Variety Vera
It is worth noting that the concept of sustainability is relative. A vine that is not susceptible to this disease may be affected by other diseases. Plant immunity depends on the composition of the soil, climate and condition of the seedlings.
Oidium is a dangerous disease that affects grape bushes. If treatment is not started in a timely manner, there is a risk of crop loss and death of all plants. Therefore, it is so important to take measures to combat the disease immediately after the first signs of a fungal infection appear.
One of the main problems that gardeners who grow grapes face almost every year is powdery mildew or oidium. This harmful disease of grapes has become widespread in all countries with developed viticulture, usually in areas with dry and hot summers. However, it is possible to save the grapes. You will learn from our article how to completely suppress oidium in early spring so that in the fall the annual vine is free from infection even in the most susceptible grape varieties.
Signs of powdery mildew: how does oidium appear on grapes
Powdery mildew (oidium) - its causative agent is the erysipid fungus (Uncinula necator = Oidium tuckeri ) , which lives on the surface of shoots, leaves and berries.
Oidium on grapes, as a rule, first begins to appear on leaves and young shoots(where he actually spends the winter) with upper (front or outer) side of the sheet as powdery gray-white coating(as if sprinkled with flour), which can be easily wiped off with your fingers.
In the photo: oidium on grape leaves
By the way! But it always appears on the underside of the leaves.
In the photo: oidium on grape fruits
And after flowering, when the fruits have set and they begin to ripen, a characteristic sign of the presence of oidium on grapes is the fact that green berries crack (previously they also become covered with a white coating), thereby outward all their insides (seeds) are turned out, which almost immediately begin rot or dry out (depending on the weather), being affected by various bacteria and fungi, and releasing a characteristic the smell of missing fish (rusty or rotten herring).
Dark spots appear on the shoots, turning black very quickly. This vine does not ripen for a long time and freezes very easily in winter.
The main danger of this fungal disease is that when it appears on grapes, it attacks them suddenly, and you can lose your entire harvest in a couple of weeks, which will simply disappear.
Important! All affected brushes must be cut off and thrown away (buried), and not in a compost pit, otherwise the fungus will return again.
The main reason provoking grape disease oidium(powdery mildew) is dry and hot weather without rain, as well as constant temperature changes (quite cold at night, very hot during the day).
It's worth distinguishing! But, on the contrary, wet weather- This main reason development
Video: description of the disease and measures to combat oidium on grapes
Prevention of oidium on grapes: when andHow to treat grapes for powdery mildew
In order not to fight oidium directly, it is necessary to take timely preventive measures to protect grapes from this fungal disease.
It is important to note that to prevent various grape diseases in early spring, it is best to use various systemic or complex drugs.
Important! Be sure to pay attention to the waiting period for the drugs used, for example, for Quadris - 25 days, and for Falcon - from 30-40 days. It is extremely important to treat your vineyards on time.
The main treatments for grapes against oidium should be carried out before flowering:
- The first treatment is carried out when 3-5 leaves appear on the grape bush (or when the flag shoot is 5-7 cm). At this moment, it is optimal to use systemic drugs (Topaz, Talendo, Impact, Skor, Rayok, Falcon, Ordan, Topsin-M, Strobi).
- The second treatment is a week and a half before flowering. It is necessary to repeat spraying with a systemic fungicide.
As a rule, such spraying should be enough to protect the grapes, and this will ensure that oidium does not appear.
By the way! Some gardeners, somewhat mistakenly, advise in early spring to spray grapes on bare vines against the appearance of powdery mildew (1-3% solution), dissolving 300 grams of the product in 10 liters of water. However, it is best to fight copper-containing drugs not with oidium, but with
If for some reason you did not carry out the spring treatment of grapes before flowering, or it did not help you, and the grape bushes and bunches still became infected and turned white, then during the period of fruit formation (grape bunches) this process needs to be approached more carefully and carefully. The point is that at this time It is undesirable to use systemic fungicides due to their rather long waiting period, it is better to use contact and sulfur-containing drugs, which have a minimum waiting period and are easily washed off by rain.
Advice! In the fall, after harvesting the grapes, you should also treat powdery mildew to try to get rid of the fungus so that it does not remain overwinter on the bush and in the ground.
Video: causes of infection and methods of combating oidium on grapes
Proper care of grapes is the best wayrophylaxis
To prevent the grapes from getting sick and not having to be treated for oidium, the plant should not suffer from a lack of moisture (that is, the grapes need to be watered correctly), and it is also recommended to regularly and abundantly feed them with potassium and calcium.
Can't be allowed in order to grape bushes, especially after cold rains, in the heat during the day they stood damp. They should be well ventilated, that is, the plantings should not be thickened, in other words, regular summer pruning should be carried out, namely pinching (pinching), and unnecessary leaves in the area of the bunches should be removed.
Note! It is best to tie grapes to trellises. Read about how to do it correctly
But the most effective method Prevention of powdery mildew on grapes means growing varieties that are not susceptible to this disease.
Thus, the grape varieties that are most resistant to oidium are considered: Krasen, Einseth, Rilines, Friendship, Bianka, Ruby Magaracha, Saperavi Dediani, Zhgia, Rubin, Frumoasa Albe, Silverstream, Lyana, Delight.
Advice! You can try (unlikely, but you can try) to protect grapes from oidium by simply planting calendula, sorrel, onions or garlic under the bush.
Video: calendula under a grape vine, which protects it from oidium
How and with what to treat oidium on grapes
Very good if you noticed white coating on the leaves even before flowering. But if you are unlucky and you find powdery mildew on the grapes already during their fruiting period, that is, after flowering, when the berries began to ripen, then you need to take the most urgent measures to combat it.
Advice! When preventing and controlling any diseases and pests, drugs should be alternated (that is, products with different active ingredients should be used) so that addiction does not occur and the effect of use is maximum.
What drugs to use
To combat this fungal disease of grapes, it is necessary to use the following drugs against oidium:
Interesting! Some sources recommend using a fungicidal contact agent such as .
Have become quite popular recently biological products (Trichofite, Liposam or Guapsin).
Advice! Very important properly handle grape bushes. You need to spray leaves and berries enough abundantly so that the solution reaches the maximum area. Concerning bunches of grapes, then it is better to process them from all sides.
Colloidal sulfur
One of the safest drugs for combating the first signs of oidium on grapes is colloidal sulfur. Its waiting period is only 2-3 days.
Important! Treatments sulfur-containing drugs (including Cumulus, Tiovit Jet, Abiga-Pik) must be carried out at temperatures above +18-20 degrees. The bottom line is that sulfur fights oidium on grapes using evaporation, therefore there is a mandatory need for warm weather.
Also worth knowing that spraying must be carried out either early in the morning, or late in the evening, or in cloudy weather so that the bunches do not get burned under the scorching daytime sun.
It is also worth considering that the period of protection for a grape bush treated with colloidal sulfur is about 1-2 weeks. And since this is a contact preparation that is easily washed off, therefore, spraying should be repeated at least every 2 weeks, or earlier if it has rained.
It is not difficult to prepare a working solution of colloidal sulfur, and it must be done correctly:
- First, pour colloidal sulfur into a jar (consumption - 30-40 grams per 10 liters).
- Gradually pour water into the container and stir until you obtain a homogeneous mass (slurry).
- Then pour the resulting concentrated solution into a bucket and stir again.
- Strain, pour into a sprayer, and then carefully process the leaves and bunches.
Video: colloidal sulfur - a simple and reliable means of oidium on grapes
Folk remedies
To remove powdery mildew and not think too much about the negative consequences during the fruiting period of grapes, it makes sense to first of all turn to folk remedies.
However, it is worth understanding that the effectiveness of such funds is extremely low.
Baking soda, iodine and potassium permanganate
A truly folk remedy in the fight against powdery mildew on grapes is to prepare a spray solution with baking soda, iodine and potassium permanganate, which can be used without fear at the berry ripening stage.
Important! This mixture of products will also help protect grapes from anthracnose.
So, the recipe for preparing a solution for oidium is as follows:
- Have to take 4-5 tbsp. spoons of baking soda or soda ash and dissolve in hot water (40-45 degrees).
- Then drip 15-20 drops of iodine.
- Pour the resulting solution into a bucket of water so that the result is 10 liters.
- Dissolve in a separate container manganese and pour it into a bucket so that you end up with light pink solution.
- Add 40 ml. liquid laundry soap so that the solution sticks well.
- Spray the resulting solution over the leaves and berries.
By the way! After this treatment, the berries can be eaten on the second day.
Video: baking soda, iodine and manganese from oidium on grapes
Wood ash
Another natural folk remedy for treating grapes from powdery mildew is wood ash.
To prepare an ash solution for treating grape bushes you will need:
- Pour 2 liter jars of ash (1 kg) into a bucket of water and stir well.
- Let it brew for 1-3 days so that the ash extract is most effective.
- Dissolve 1 liter of the resulting extract in a bucket of water.
- Add 3 tbsp. spoons (40 grams) of liquid laundry soap (for better adhesion).
- Strain, pour into a sprayer and process.
By the way! Wood ash is also an excellent potassium fertilizer, that is, it is an excellent foliar feeding.
Video: wood ash is a miracle remedy for powdery mildew on grapes
Milk serum
Another safe way to combat oidium on grapes is to spray them with whey.
The working solution is prepared in the following proportion: 1.5 liters of whey are dissolved in 10 liters of water.
It is advisable to carry out this treatment at least once a week.
Also, in the fight against powdery mildew on grapes, some summer residents advise using garlic infusion (250 grams of crushed cloves per 10 liters of water, 24 hours).
Important! It is worth understanding that folk remedies are relatively weak means for treating oidium, which are not suitable for combating if the disease is rampant in full force in the vineyard.
If you want to end up with a luxurious and high-quality grape harvest, you need to make every effort to protect it from powdery mildew. To do this you must use both traditional methods, as well as more effective chemical and biological ones. The main thing is not to miss the onset of the disease, and if you haven’t noticed an outbreak, continue to fight systematically and regularly.
Video: how to deal with powdery mildew (oidium) on grapes
In contact with
"is called a fungal infection of the grapevine, its leaves and fruits. This fungus spreads quickly among plants, so it must be eliminated in time to prevent the rapid death of the entire vineyard. To do this, you can use both chemicals and folk remedies.
Powdery mildew (or oidium) at first glance looks like ash, hit the plant in large quantities. This fungus also feels like ash or ash to the touch and is easy to wipe off the leaves with your fingers.
Usually has a grayish color, but if the disease affects grapes in early summer, when humidity is relatively low, oidium may be white.
Where does oidium come from?
Spores are present in the air or on other plants on the site. In dry hot weather, fungus remains in latent form, and even if it gets on grapes, it does not affect the fruits and leaves.
With dampness and moisture, spores are activated and begin to spread primarily along the surface of the leaves, and then throughout the vine. If this disease is not eliminated in time, it also affects the fruits.
Why is powdery mildew dangerous?
If destruction measures are not taken in time, the following consequences are possible:
- reduction in the total harvest volume due to loss of peduncles;
- death of vines and leaves;
- loss of berries.
Those fruits that still remain cannot be used in cooking or fresh, as they lose their taste and can be hazardous to health.
Signs of appearance
Signs of development are:
- Slow growth.
- Curling leaves inward.
- No pests or cobwebs are found on the unfolded leaves, but there are brown spots and a whitish or gray coating.
Oidium can infect grapes not only at the beginning of summer, but also later - during the period of flowering and fruit formation.
In such cases, the flowers will dry out quickly, and brown spots will spread on the berries.
How to fight and what to treat for treatment?
Processing is carried out taking into account the following features:
- 100 grams of sulfur must be dissolved in ten liters of water.
- All plants are sprayed with the resulting mixture in the morning or evening.
- The procedure is carried out daily for one and a half to two weeks, depending on the degree of damage and the effectiveness of the method.
If you reduce the concentration by half, the composition can be used in the spring as a prophylactic agent. If sulfur does not help, it is necessary to use stronger biological agents or ready-made preparations.
Biological drugs
One of these remedies is humus. It is poured into a hundred-liter barrel in an amount that will take up a third of it. The remaining volume of the barrel is filled with warm water, then the container must be covered with a dense fabric that allows air to pass through for one week.
After this time, the liquid from the barrel is filtered to remove humus and used to spray on grapes. Just two sprayings per season with an interval of 7 days are enough. Additionally, the procedure can be carried out after the start of flowering, if signs of oidium begin to appear on the inflorescences.
An alternative remedy is the drug phytosporin, which has the following advantages:
- the product is safe for people and animals;
- due to its wide spectrum of action, phytosporin simultaneously fights fungi, bacteria and harmful insects;
- additionally has a protective effect, creating a protective layer on the treated surfaces that prevents the development of diseases.
Fitosporin is sold in gardening stores in the form of a white powder or dark paste. Before use, it must be dissolved in water in accordance with the instructions in the instructions.
Chemicals
The most effective are chemical concentrated broad-spectrum agents.
These include:
- Aktara;
- Acrobat;
- Rubigan;
- Speed;
- Byleton;
- Vitaros;
- Topaz.
Such substances are very effective; they can harm the plant if the correct dosage is not followed when preparing a solution from concentrate. They can also leave chemical burns on your hands, so it is recommended to wear protective gloves and long sleeves when preparing the solution and spraying.
Folk remedies
When preparing them, it is also necessary to observe the proportions of the components used so as not to damage the plant and at the same time achieve the desired effect.
The most effective are the following formulations:
- One part mullein pour in three parts of water and settle for three days. The finished composition should be diluted again with water in a ratio of 1 to 3.
- For 4 liters of water add a tablespoon of liquid soap and three tablespoons of soda. The composition can be used immediately.
- For ten liters of boiling water add two tablespoons of mustard powder and mix thoroughly. You can spray the grapes only after the mixture has completely cooled.
- Sifted ash in an amount of one kilogram is diluted in 10 liters of warm water and infused for five days. Once a day, the composition must be stirred so that the ash does not settle in lumps and dissolve. Before use, add a tablespoon of grated laundry soap.
can be used once every few days over a long period, since these the compositions are not dangerous for the plant. But if no effect is observed from them after two weeks, it is better to use store-bought chemicals that will cope with the fungus at any stage of its development.
Prevention in spring, summer and winter
It is impossible to completely protect a plant from diseases and pests, but you can reduce the risk of powdery mildew by if you follow these preventive recommendations:
- during the growing season, grapes can be sprayed with one percent Bordeaux mixture;
- at the first signs of oidium, it is necessary to stop feeding, since the components included in it only contribute to the development of the fungus (with the exception of phosphorus-potassium fertilizers);
Recently, many summer residents are faced with a disease such as powdery mildew (oidium). This disease affects almost all garden crops, and especially grapes. The harvest produced by bushes affected by fungal diseases is unsuitable for either food or winemaking. Let's look at why powdery mildew appears on grapes, how to get rid of the disease, and what preventive measures can be taken to prevent it.
Causes of powdery mildew on grapes
Oidium is a fungal disease. We will not go into details of the reproduction of fungi that cause the disease. It is enough for a summer resident to know that with high humidity the disease develops rapidly. Excessive amounts of nitrogen fertilizers also contribute to the appearance and development of the disease.
Signs of powdery mildew
The disease can be determined by appearance plants, and at a slower rate of growth. The grape leaves begin to curl inward. However, the same thing happens to a plant damaged by a leaf roller. But, if you unfold the leaf and find neither a pest nor a web, then the problem is powdery mildew.
Also a sign of powdery mildew is the presence of brown spots on the shoots and leaves of the plant, and slow growth of the grapes. If we are talking about the flowering period, then under the influence of a fungal disease the flowers dry out and brown spots appear on the berries. Over time, the bunches of berries dry out before they have time to ripen.
Methods to combat fungal disease
Currently, there are 3 groups of methods to get rid of powdery mildew:
- biological;
- chemical;
- folk remedies.
Let's look at each of these methods separately.
Biological control method
To treat powdery mildew in grapes, humus is most often used, which is prepared in a certain way. We take a container with a volume of 100 liters and fill it 1/3 with humus. Then, fill the container to the brim with water, the temperature of which is 250C. After that, cover it (preferably with thick burlap) and leave it warm for 6-7 days. During this time, stir the contents of the container daily. Before using the composition, filter it through gauze folded in several layers. As a result, we obtain concentrated saprophytic microflora that effectively fights fungal diseases.
You need to spray the grapes with the resulting solution at the beginning of spring, when they have released their first leaves and buds have appeared. To treat the plant, we use a sprayer into which we pour the prepared solution. We process the grapes in the afternoon, or preferably in the evening. For processing, you should choose cloudy, but not rainy, weather.
To prevent the appearance of powdery mildew throughout the entire period of flowering and ripening of grapes, you should treat it 2 more times: a week after the first treatment and before the plant blooms.
If the degree of infection is high, then after the grapes have faded, we spray them with concentrated saprophytic microflora several more times. There should be an interval of 7 days between treatments.
Using a biological method to combat powdery mildew allows you not only to get rid of the fungal disease, but also to strengthen the plant.
Chemical control methods
This method involves the use of insecticides. Despite the fact that it is the most effective, gardeners resort to it only if nothing else helps. This is due to the fact that all insecticides, without exception, contain substances that are unsafe for health, which enter the human body along with the berries. The packaging of each drug indicates how long before harvest it can be used. These recommendations must be strictly followed.
When choosing how to treat grapes against powdery mildew, you should pay attention to the chemical composition of the drug. The most popular today is phytosporin. This drug is prepared on the basis of Bacillus subtilis. Scientists to this day cannot come to a common conclusion regarding the harm of this substance. But they definitely agree that this drug is the most harmless among insecticides for fungal diseases.
In addition to phytosporin, drugs such as strobi, topaz, thanos, thiovit and chorus are effective in combating powdery mildew on grapes. Some drugs are available in powder form, some in concentrate form, and some in paste form. It is most convenient to work with concentrates, which simply need to be diluted with water in a certain proportion.
After the berries appear, and throughout the entire fruiting period, use chemical methods It is impossible to fight oidium.
Folk recipes
Many summer residents know how to deal with powdery mildew without using insecticides. The advantage of folk remedies is their harmlessness. Let's look at the most popular recipes for powdery mildew.
Recipe 1
To prepare a solution that can be used to treat grape bushes against powdery mildew, we will need 4 g of soda ash and laundry soap, and 1 liter of water. You should use water that has been standing for a while. First, dissolve baking soda in water. Then, add soap to the resulting solution.
The resulting solution is used to treat powdery mildew on grapes. You can process the plant at any time, regardless of whether the berries have already appeared or not. To cure grapes, treatment must be done 2 times with an interval of 7 days.
Recipe 2
To get rid of a grape disease such as powdery mildew, ash, which needs to be dissolved in water, and green soap will help. For 7 liters of liquid you need to take ½ bucket of ash. Leave the resulting solution for 24 hours to infuse. Then, dilute the solution with water in a 1:1 ratio and add 10 g of soap. The product is ready for use.
If you don’t have time to wait for the ash to infuse in water, you can boil it (20-30 minutes).
Recipe 3
To prepare another remedy that can be used to treat oidium, we need straw dust and water. Instead of straw dust, you can use manure. We take the ingredients in a ratio of 1:3 (1 part dust or manure to 3 parts water). Leave the resulting mixture for 72 hours. After the time has elapsed, add 3 parts of water to the solution. The product is ready for use.
The leaves and stems of diseased grapes should be treated in the evenings. This can be done with any frequency. If we are talking about preventive treatment, then it is enough to spray the plant 3-4 times per season. If the grapes are affected by oidium, then it is advisable to spray them several times a week.
In addition to the above recipes, iodine, potassium permanganate and soda are suitable for processing grapes.
Prevention of powdery mildew on grapes
Treating grapes for powdery mildew is quite a difficult task. It is much easier to prevent the occurrence of a fungal disease than to treat it.
Agrotechnical measures such as tying up shoots and breaking them off will help prevent the occurrence of fungal diseases, one of which is powdery mildew. You should also pay attention to weed control. In the presence of a large number of harmful plants, humidity increases, which contributes to the appearance of fungus. Also, agrotechnical measures used to combat oidium include pinching.
There are video and photo lessons describing how to properly tie up shoots and care for bushes. But, in fact, the only thing you need to do is to ensure good air circulation. If the grapes are sick, then the damaged shoots and leaves should be broken off and burned or taken away from the summer cottage.
The use of sulfur for the prevention and treatment of disease
As a preventative measure, you can treat the plant with a sulfur solution. To prepare it you will need 10 liters of water and about 35 g of sulfur, which can be purchased in specialized stores. Processing is carried out in the mornings or evenings. If you spray grapes in bright sunny weather, burns will appear on the leaves and berries, which will negatively affect the yield of the plant. This solution can also be used to combat powdery mildew. But the sulfur concentration will have to be increased. On average, 90 g of sulfur is taken per 10 liters of water.
ASH IS A MIRACLE CURE FOR OIDIUM. Powdery mildew on grapes vselennaya uvlesheniy
Oidium of grapes. Control measures.
A sign of downy mildew is the presence of oily spots on the leaves, on top of which a white coating appears when the air humidity increases. As the disease spreads, a white coating appears on the berries. With oidium, the berries and leaves become covered with brown spots.
When growing grapes, special attention should be paid to measures to protect against diseases and pests. When the plant is already affected, it is necessary to quickly cure it, otherwise you can lose the entire harvest. One of the common diseases of grapes is oidium. What kind of disease this is and how to treat it, we will consider in more detail in this article.
General information about the disease
Grape blight is a fungal disease that affects all green parts of the plant and spoils the fruit, making it unfit for consumption. The disease also has a second name – powdery mildew. The fungus spreads most actively in the hot season. However, the spores survive winter without problems.
A humid environment also creates favorable conditions for disease progression. At high level Air humidity causes fungi to spread on dry plant tissues. Oidium prefers moisture and warmth, but not water. Therefore, during periods of frequent rains, the fungus may stop reproducing.
Causes of infection
Even a small amount of spores getting on grapes already creates big problems for the plant. The first stage of the disease is not expressed in anything. The first signs of damage appear after one to two weeks.
Signs of defeat
The first signs of the disease may appear in the spring if the disease affected the plant in the previous season. Young stems are covered with a white or light gray coating.
Externally, the plaque resembles flour or ash. Over time, the shoots begin to turn yellow. Spots form on the leaves of the plant. Gradually the leaf begins to bend and dry out.
You can also make sure that the grapes are affected by powdery mildew by using the peculiar smell that will come from the plaque if you rub it a little with your fingers. The aroma will resemble the smell of rotten fish. If the spread of the fungus is not stopped in time, the grapes will slow down in development and may die.
In summer, powdery mildew attacks berries. Fruits may not form on the bunches at all, and if grapes do appear, then dark-colored spots form on their surface, which over time begin to crack and rot.
Even if the affected berries continue to grow and ripen, they cannot be eaten or used as raw materials for the preparation of alcoholic beverages. Such grapes will taste unpleasant, as they are very sour with a taste of mold and rot.
Preventive measures
Prevention of the appearance and spread of powdery mildew is very important when growing grapes. The fact is that in the initial stages the disease develops without visual manifestations. The appearance of plaque already indicates the spread of fungi. The most effective way to prevent the spread of this disease– plant grape varieties that are highly resistant to oidium.
Don't forget about proper care behind the vineyard. The plant should receive enough sunlight and be well ventilated. Therefore, it is necessary to carry out timely pruning of the stems and use trellises for gartering the grapes.
When watering, you should carefully pour water without getting on the leaves of the grapes. At the end of autumn, it is recommended to treat the plant and soil with iron sulfate. You can also plant crops such as onions, garlic and dill next to the grapes.
Particular attention should be paid to feeding grapes. It is best to avoid nitrogenous fertilizers or limit their use as much as possible, since these preparations create favorable conditions for the spread of powdery mildew.
For prevention, you can also use drugs that are intended to treat grapes.
However, it is worth considering that the solution prepared for the purpose of spraying grapes for prevention should be less concentrated. For preventive purposes, a fungicide such as Fundazol is ideal.
Treatment options
Today, there are quite a large number of methods to combat powdery mildew. For advanced forms of the disease, it is best to use an integrated approach.
Drugs
Chemical compounds are quite effective in combating powdery mildew. However, it is better not to use them during the berry picking period, so that a large amount of harmful substances does not remain on the fruits. The best option is treatment during flowering or after harvest. It is best to treat the plant with products that contain sulfur and a fungicide of organic origin.
Such drugs as “Karatan EC” and “Karatan LC” have proven themselves well. "Karatan EC" is a drug for a narrow purpose. The product is mainly used to treat plants against powdery mildew. This composition can be used if the air temperature does not exceed 30 degrees. Otherwise, the product may damage the grape leaves.
“Karatan EC” does not have the property of penetrating plant tissue, therefore, when precipitation falls, it will be completely washed off from the grapes. The drug "Karatan LC" is resistant to water and does not dissolve in it. It is believed that Karatan EC is best used for the prevention of powdery mildew, and Karatan LC for treatment.
In addition to the drugs of the “Karatan” group, drugs such as “Triadimefon” and “Rubigan” will help fight oidium. "Triadymethon" is also known as "Bayleton". The drug affects grapes through roots and tissues. In the soil, the substance remains active throughout one growing season.
The greatest effect from treatment with this product is observed when spraying grapes in the early stages of oidium. The process of plant healing begins on the third day after treatment. The protective properties of the drug remain for a month from the moment of spraying.
"Rubigan" is characterized by a high rate of penetration into grape tissue. Unlike Bayleton, the drug does not have a protective effect for as long (up to two weeks). The product can be mixed with other fungicides and fertilizers of mineral origin.
Biological methods
Biological methods of combating fungal diseases involve the use of products of organic origin. In order to independently prepare a solution for processing the vineyard, you will need humus. The preparation of the composition must be carried out in the spring in order to process the plants in time.
In addition to humus, you will need a container with a capacity of one hundred liters and water. Humus is placed in the container to one third of its volume. Then warm water (not lower than 25 degrees) is poured into the container. The top of the container should be covered with a rough, durable cloth. This composition must be kept for a week, removing the fabric daily and stirring the contents of the container.
After the specified period, the infused mixture must be passed through cheesecloth. The resulting liquid is sprayed on the vineyard in the afternoon.
This remedy can be used not only for treatment, but also for the prevention of oidium.
Folk remedies
For the prevention and treatment of oidium, you can use not only special-purpose chemicals, but also use folk recipes. The simplest option is a soda solution. To prepare it, you will need six tablespoons of baking soda, eight liters of warm water and two large spoons of liquid soap or dishwashing detergent. All components are mixed until a homogeneous mass is obtained, which must be used to treat the bushes immediately after preparation.
Another effective option is to make a composition based on Bordeaux mixture and sulfur. The components are mixed with each other in equal quantities. It is necessary to treat grapes with this composition in dry weather, since precipitation will reduce the effectiveness of this product.
An environmentally friendly means for treating bushes is ordinary ash. Microfertilizer must first be sifted and then mixed with water. Ten liters of liquid will require one kilogram of ash. It is advisable to leave the solution for five days, stirring it periodically.
To make the mixture easier to settle on the grapes, it is recommended to add thirty grams of soap shavings to it before spraying.
Another harmless remedy for treating grapes against oidium is a decoction of tansy. To prepare the solution, you will need 300 grams of crushed flowers of a fresh plant or 30 grams of a dry mixture, which can be purchased at a pharmacy. The raw material must be poured with ten liters of water and left to brew for one day.
After a day, the mixture must be simmered over low heat for two hours. Then the broth must be cooled and passed through cheesecloth. The resulting liquid is used to water the soil at the roots of the plant and between the rows in the vineyard.
If signs of the disease appear on the grapes just before picking the berries, a solution of potassium permanganate will help stop the spread of the fungus. To prepare the product, you need to dilute five grams of the substance in ten liters of water and spray the bushes with the resulting composition.
There are several more simple recipes, which can be used to treat grapes from powdery mildew:
- A solution of mustard powder (two large spoons) and hot water (ten liters). This composition can be used for both spraying and watering. The solution must cool down before use.
- One hundred grams of crushed garlic cloves must be mixed with four liters of water. The mixture is allowed to brew for 24 hours, after which the plant is treated with it.
- Cow dung is mixed with water in a ratio of one to three. The resulting mass is infused for three days, after which it is filtered and water is added. The amount of water added should be three times the volume of the strained infusion.
