General information

How to save petunia from powdery mildew, correct methods


Petunias adorn many gardens, balconies, verandas and city parks. This beautiful unpretentious flower came to us from Brazil. And for some reason there he was called “tobacco”. And later, these flowers were isolated in a separate form and called petunia (tobacco in Brazil is called petun).

In Russia, petunia appeared in 1839. In 1855, the first representatives of terry varieties were bred. In 1881 created large-flowered petunias. In the middle of the last century, breeders brought out ampelous and cascade varieties of petunias, which grow faster than usual. With good lighting, the main shoot and many side shoots quickly form.

Now small-flowered petunias are very popular, the diameter of their flowers is no more than 4 cm. They are very decorative. They are planted in flowerpots, flower beds, hanging pots, they are decorated with unsightly walls of houses and other buildings. Used in vertical beds. Such multi-colored clouds look very impressive.

Petunias are unpretentious in care, but still sometimes with improper care they can be affected by such diseases as

  • powdery mildew,
  • gray rot
  • blackleg.

Further, what is powdery mildew on petunias is how to deal with it.

Causes of illness

Sometimes novice gardeners notice a white bloom on petunia leaves and don’t know what to do or what kind of trouble. This attack is called powdery mildew. This disease is caused by fungi, which are activated in wet weather, so it is important to observe the regime of irrigation.

Pathogens may be:

  • in the land on which the flower was planted,
  • in water for irrigation,
  • spread from neighboring plants by wind or insects,

A person himself can transfer fungal spores on tools or hands. Humidity above 60-80% and lowering the temperature below 18-20 ° C - excellent conditions for the course of this disease, especially with an excess of nitrogen in the soil.

With a very thick planting plant airing becomes impossible, which leads to the disease. Such planting must be thinned.

Important! After working with a diseased plant, it is necessary to treat the tools and hands with an antiseptic.

Powdery mildew (spherotek) appears as a white patina on petunia leaves. Indeed, it seems that the leaves are filled with flour or icing sugar. After hitting the leaves, the infection can spread to the stems, buds and hit the whole plant. Therefore, it is necessary as soon as possible to begin treatment.

Having settled on one leaf, the parasite fungus quickly pulls all the juices out of it, feeding on them, and when touched it moves onto others. For a couple of days under suitable conditions, the entire landing can become infected. At first, very small white specks are visible on the leaves, gradually they grow and the whole flower looks as if showered with white powder or flour. The disease progresses very quickly, the fungus leaves turn yellow and fall off. And the newly grown leaflets are often twisted, unsightly. In cases where the treatment is delayed or not performed at all, the plant dies.

Important! The spores of the fungus enter the soil, they winter there beautifully on old dried leaves, on the bark of the tree, and the next year, under suitable conditions, they parasitize on new plants.

Downy mildew

Downy mildew

Along with the usual there is downy powdery mildew. It affects only the green areas of the plant, its raid is somewhat "fluffier" than that of the normal one. If powdery mildew appears at low air temperatures and high humidity, then a false disease appears when there is a lack of moisture.

Fight against false mealy

If the flower bed was struck with a false mealy, the following treatments can be applied:

  • Pour 10 drops of iodine and 1 l of cow's milk into a bucket of water, mix everything well and treat sick specimens,
  • Spray solution of polycarbocin,
  • Spray copper oxychloride solution.

Any of these formulations are sprayed on the plant.

Petunia treatment

Many novice gardeners care about why petunia leaves turn white and how to get rid of this scourge. At the first manifestations of infection, treatment should begin. After all, the entire garden may perish in a very short period of time. To destroy a harmful fungus, do the following:

  • Cut out all the leaves, shoots or buds that are covered with white bloom,
  • Cut off the ground under the plant,
  • Put in place of the excavated soil a new one, treated with preparations against fungal diseases,
  • Spray the whole bush fungicides: Fundazol, Topaz or Vectra.

Also help in the fight against powdery mildew:

In order to prevent mold on petunia leaves, it can be treated with phytosporin, but this biofungicide is ineffective for treatment.

Important! When working with fungicides must comply with security measures.

Folk remedies against powdery mildew on petunias

Petunias have been cultivated here for a very long time and there have not always been all sorts of chemicals, gardeners have perfectly fought with powdery mildew with home remedies. Similarly, damaged leaflets were removed and the plants were treated as follows:

  • Copper sulfate. Dissolve 5 g of vitriol in 5 liters of warm water, add 50 g of planed soap (so that the solution is better retained on the parts of the plant). The resulting solution to process the bushes of petunias once a week for a month.
  • Manganese potassium. 2-3 g of manganese dissolved in 10 liters of water. To process plants in 5 days 3-4 times.
  • Soda solution. 2-2.5 tablespoons of soda ash dissolved in 5 liters of hot water, add 1 tbsp. spoon planed soap, stir everything until smooth. Warm the solution of petunia bushes and the soil under it in 7-10 days 2-3 times with a warm solution.
  • Sour milk whey. 1 liter of serum mixed with 10 liters of water and carefully spray the plants.
  • Another interesting way: 1 cup of cow's milk, 3 tablespoons of water, 1 tsp of salt. All well mix and process the affected leaves and stems.
  • Mullein. 1 liter of mullein is diluted in 3 liters of water and infused for 2-3 days, then diluted in a ratio of 1:10 and treated plants.
  • Furacilin. 10 tablets of the drug dissolved in 5 liters of water and process the flowers.
  • Garlic. 25-30 g of garlic must be crushed, pour 1 liter of water, insist during the day and process the plant.
  • Mustard. 2 tablespoons of dry mustard diluted in 10 liters of water. Insist 3-5 hours and process.
  • Horsetail. 100 g of chopped horsetail must be poured with 1 liter of water and allowed to brew for a day. Then it is necessary to boil over low heat for about 1-2 hours. After that, strain, cool and dilute with water 1: 5. Spray petunia bush. Best of all from a spray bottle. This solution can be used both for treatment and for the prevention of powdery mildew. Spraying should be done once a week.

Important! Folk remedies are effective if the disease is noticed at the initial stage (no later than 4-5 days). Then it is necessary to connect the chemistry.

Any methods of treatment, both chemical preparations and folk remedies, should be carried out in cool weather or in the evening so that the plants do not get burns.


As you know, any disease is easier to prevent than to cure. For flowers, this applies to the same extent. For the prevention of powdery mildew, petunia bushes should be planted not very thickly, so that there is good ventilation, and also to monitor the irrigation regime with special care. You can not completely dry a clod of earth, and then pour it thoroughly. Or vice versa, do not let the soil dry out. In such cases, the plant is reduced immunity. To prevent disease, you can use the following substances:

  • Ash. Wood ash is drawn in water (1 kg wood ash 10 liters of warm water) for seven days, then the solution is drained from the sludge and added with soap (for this amount of the resulting solution - 2 tablespoons) and then treated with petunia from a spray bottle. The remaining sediment (ash) can be poured onto the soil under the plant root.
  • Onion Husk They make an infusion: you need to take about 200 grams of husk on a bucket of very hot water and leave for 2 days. Spray the plants filtered infusion. This method can be used before the appearance of flowers.

The better to fight the fungus

What to apply for the treatment of each gardener decides for himself, relying on:

  • the effectiveness of the drug
  • drug price
  • quantity in packaging.

This is a broad-spectrum fungicide. Due to the presence in the composition of benomyl, he is very successfully struggling with various diseases. After transformation in the plant, carbendazim shows its best qualities. Fully foundazol in the plant is not absorbed, most of it remains on the leaves, which does not allow the plant to become infected again.

Amistar extra

It is an integral fungicide that helps fight various diseases. As a result, the growing season increases, photoassimilation improves, nitrogen exchange improves, ethylene formation is suppressed.

This drug is used for the treatment and prevention of powdery mildew and some other diseases. It should be borne in mind that Tospin-M is not effective against downy mildew.

Observing the rules of agricultural engineering, it is impossible to protect the plant 100% from powdery mildew infection, but the risk of infection can be reduced quite significantly. And the time spent treatment will help save a beautiful plant.

What is dangerous and where does it come from

Fungal mycelium, which are the causative agents of the disease, live in the soil and make themselves felt at the first favorable conditions for them. Often the factors contributing to the activation of these parasitic formations are cold rainy weather and poor care.

Did you know?Petunia was first discovered by botanists in Uruguayan surroundings and credited to the genus Tobacco. Therefore, the flower was originally called Nicotiana axillaris.

According to experts, lead to the development of powdery mildew foci can:

  • excessive amount of nitrogenous substances in the flower pot,
  • lack of good ventilation of the plant, which is caused by too thick sowing (such specimens must be thinned out),
  • illiterate watering, when the florist allows the earthen coma to completely dry, and then pours it heavily with water, or, on the contrary, when it moisturizes without waiting for the surface ball to dry,
  • adverse weather conditions, when air humidity reaches above 60%, at a temperature of 15–25 ° С (this cause of the disease applies only to street petunias),
  • contaminated irrigation water
  • a neighborhood with diseased plants or contact with hands that have touched infected lesions,
  • radical rejuvenation of the bush,
  • sudden changes in temperature,
  • spread by the wind of fungal microorganisms.

Important!Infected petunias are disinfected by sprinkling with special preparations and watering. In the case of indoor plants, the sill is treated with a sill, a pot and a tray.

Methods of struggle against the "scourge"

When it is too late to carry out preventive measures and there are obvious signs of illness on the flower, proceed immediately to treatment. The first thing to do in such a situation is to isolate the petunia container from the healthy neighbors. Cut off all the affected areas, even if they have not yet had time to open buds. These residues will need to be burned in order not to spread the infection in the garden.

Important!Small petunias, which are attacked by powdery mildew, are completely dipped into the treatment solution. Thus, both land and green mass are disinfected.

If we are talking about a room flower, then it must be transplanted into a fresh substrate. A ground around the garden petunias sprinkled with a 2-cm layer of wood ash. Further disinfection depends on the degree of infection and your preferences. You can use folk remedies to combat powdery mildew or agrochemical inventions.

Mealy dew infects orchards (currants, gooseberries, grapes, peaches, apples, cherries) and garden crops (cucumbers, tomatoes, cabbage, carrots, zucchini, melons).

Folk recipes

Experienced growers are advised to resort to these funds for the purpose of prevention and in the initial stages of infection. The desired effect will be possible if fungal mycelium attacks your green darling for no more than 4 days. Otherwise, all efforts will be in vain.

If you have time with the deadlines, try to prepare an "explosive mixture" of wood ash. To do this, you will need only 200 g of the product, 5 liters of water heated to 40 ° C, and 30 g of liquid soap. Mix everything well, let it sit a little. Sprinkle with a two-day interval and carefully observe the condition of the plant. In addition, add another 5 liters of water to the remaining solution and pour over the well.

Did you know?The asteroid, which was discovered in 1921, is named after the flower.

An alternative solution is iodine solution, which is prepared in a ratio of 1 ml / 1 l. Soda ash also has an overwhelming effect. 10 g of powder per 2 liters of hot water and 1 teaspoon of liquid soap is enough for treating the culture three times with a weekly interval. Garlic or onion peels in tandem with hot water and iodine give good results. The only drawback of this method is the need to insist the solution for 48 hours. When the tool is ready, the plant will need more powerful drugs.

To prevent the spread and activation of fungal mycelium is quite possible with a solution of potassium permanganate (potassium permanganate), milk and whey. In the reviews, growers note the high effectiveness of the above methods and even compare them with known fungicides. For example, they write that the drugs "Phenarimol" and "Benomil" lose in performance with milk diluted with water in a ratio of 1:10.

Did you know?Foreign farmers who specialize in environmentally friendly products prefer dairy products to deal with powdery mildew.

If the disease progresses for about a week, it will be necessary to save petunia with strong chemical or biological preparations. Of the many developments of agrochemistry, impeccable reputation among such:

  1. Copper sulfate. The working solution is prepared in a ratio of 50 g per 10 l of water. Spraying is recommended to be carried out only once a season, therefore it is better to do this with a preventive purpose in the spring.
  2. Sulfur colloid. It is enough to dissolve 30–50 g in a 10-liter bucket of water. But the air temperature during processing should not be below 20 ° C, otherwise the fungus will not be destroyed. In the heat, when the thermometer rises above 32 ° C, it is better to refuse sprinkling.
  3. "Topaz". For the purpose of treatment, the solution is disinfected in the proportion of 2 ml per 10 l of water. Sprinkling is repeated after 3 days. Only 3 treatments are allowed, but often the flower recovers after the first time. In case of prophylaxis, re-disinfection is recommended after 12 days.
  4. "Fundazol". It is a very effective chemical, but, unfortunately, it is sold for sale only in large packages (5–20 kg each). The solution is prepared in a proportion of 10 g per 10 l. Allowed 2 sprinkling.

Did you know?Petunia entered the landscape gardening design in triumph in 1834, when its first hybrid bloomed.

Among the biological fungicides are leading "Fitosporin", "Alirin-B", "Pseudobacterin". These substances are more suitable for preventive spraying of petunias than for treatment. In any case, the flower must be disinfected generously, so that the pesticide gets into all parts of the plant and into the soil as well.

Now you know how insid mealy dew and how to deal with it. Of course, it is always easier to prevent a disease than to cure it.

Briefly about the plant and its features

Cascade and ampelous petunias grow faster than normal. If you solve the problem with additional lighting, quickly formed a central shoot, and then the side, departing from it at a right angle. With a lack of light, side shoots grow worse and grow upwards. You can adjust the shape of the bush by changing the conditions of detention.

Experienced growers pinch the bushes during growth. They do this to slow down the development of petunias. Breeders brought hybrid varieties, laying in them the beautiful shape of the bush. When growing them, they do not use special agrotechnical techniques. They will be needed for seed reproduction of ampelous petunias: the bush is formed by nipping, but still it will not be possible to turn it into an attractive “ball”.

Basics of the disease

The mildew or mycelium of the parasitic powdery mildew fungi is a parasite that invades the cells of the petunia and drinks all the juice from it. If you look at the white bloom, soon the lower leaves will turn yellow, hang and fall off.

In those places where mycelium is attached, ulcers appear. Living tissue disappears as the parasites "eat" it. It is hard not to notice powdery mildew: the lack of nutrients affects not the best way on petunias. Due to the violation of the process of photosynthesis, it will die if not to take urgent measures of complex struggle.

Mealy dew is a fungal disease caused by parasites that inhabit the upper layers of the soil. Она редко поражает петунию, если цветовод заботится о ней. Он знает, что споры мучнистой росы активизируются в следующих случаях:

  • Прохладный сырой воздух (дневная и ночная температура держится в районе +20 градусов по Цельсию, а влажность воздуха превышает 70%).
  • Избыток азота в грунте.
  • Загущенность насаждений.
  • Неправильный и нерегулярный полив.

Иногда петунию поражает мучнистая роса по другим причинам. Infection does not occur due to non-compliance with the conditions of detention. The pest comes to it from neighboring crops, through water or due to non-compliance with precautionary measures by the florist himself (cutting a non-healthy plant with the same tool without treatment with an alcohol solution).


For the first time about powdery mildew started talking in the Russian Federation at the beginning of the XX century. Its pathogen is the fungus Sphaerotheca pannosa. Easy to recognize infected plant:

  1. First, a whitish bloom appears. It is visible on the leaves and inflorescences.
  2. After a few days, droplets that look like dew appear on the stems and petals.

Experienced growers claim that the disease spreads from the lower leaves to the upper parts, including the buds. Without taking action, the plant will rot and die.

How to get rid of the problem?

To cure petunia, review the conditions of detention:

  1. It is watered less often and only after it is noticed that the top layer of soil is dried out.
  2. The flower grower stops spraying it, and the flower pot is rearranged on the window sill, which “sinks” in the sun.
  3. It breaks off the leaves, which are located close to the edge of the ground. This simple action prevents the spread of the disease to the upper parts of the plant.

Not all growers use drugs in the fight against powdery mildew, even knowing about their effectiveness. They believe in favor of popular methods. Petunia will recover if it is treated with a solution prepared from:

After mixing the ingredients listed above, pour it into a bottle and spray petunia with a spray bottle.

Algorithm for the treatment of fungicidal drug

  1. Changing the conditions of the plant. It is cleaned on the window sill sunk in the sun and less often watered with petunia.
  2. Remove infected areas, i.e. buds, yellow and flabby leaves.
  3. Remove the top layer of soil, and instead pour another - treated.
  4. Spray fungicides, spreading them according to the manufacturer's instructions.
  5. Make sure that the solution gets to all parts of petunia.
  6. In severe cases, dip the plant in a container with a solution.

Effective folk remedies

  1. Soap solution with the addition of soda ash. For its preparation take 20-25 grams of soda, 5 liters of hot water and 5 grams of liquid (chopped household) soap. The mixture is cooled, and then it is sprayed with a basal patch of soil. The frequency of the procedure - 2 times in 7-10 days. Do not spend it, seeing that the signs of powdery mildew are gone.
  2. Weak potassium permanganate solution. It is prepared by dissolving 2-3 grams of potassium permanganate in 10–13 l of water. The processing frequency is once every five days. The number of procedures - 3.
  3. A mixture of soap and ash. It is prepared from 1 kg of wood ash and 10 liters of hot water. After mixing and infusion for 5-7 days, add another 5-10 grams of soap and process the shrub. Before this filter it. Ash is not thrown out and poured into the pot for feeding.

What is the "chemistry" is better to handle?

In the fight against powdery mildew help fungicides. They destroy the structure of the fungus, inhibiting its development in flower cells.

This fungicide has a wide spectrum of action. It helps if you find diseases of the leaves, buds and seeds on houseplants. The effectiveness of Fundazol is due to the presence in the composition of benomyl.

This substance enters the plant through the leaves and roots. After that, it is converted to carbendazim, which exhibits the best properties of the fungicide. After processing, Fundazol remains on the surface. Only partially he gets into the plant. Because of this, petunia is better protected from repeated infection with powdery mildew.

Fundazol is sold in a 10 gram sachet. Price - 17 rubles. Method of breeding - 1 gram / 1 tsp. water. After preliminary dissolution, the volume of the working solution is brought to 1 liter.. It is better to combine watering with spraying to remove the fungus. During the season, the plant is treated twice, if it was not possible to destroy it from the first time.

Preventive measures

Mealy dew is a common disease. If you follow the recommendations from the list below, petunia will never get sick.

  • Growing petunia in a pot on a well-lit window sill.
  • The pots on the windowsill are placed at an impressive distance from each other to prevent the spread of fungal spores.
  • If the petunia does not have a living place, destroy it, so as not to infect others.
  • The plant is watered in the morning to increase its resistance to diseases.
  • If you feed it, then only phosphate and potash, and not nitrogen fertilizers.
  • It is necessary to spray it with decoction of horsetail or tansy from time to time.

Powdery mildew spraying

To treat powdery mildew for petunias, follow the algorithm:

  1. Remove all infected sites. This applies to buds, as well as yellowed and turgorless leaves.
  2. Remove the top layer of soil and replace it with the treated one.
  3. Spray with a special preparation (foundation, topaz, etc.).
  4. Make sure that the solution covers the entire plant.
  5. For greater effect, you can dip the plant in a container with the prepared solution.

As you know, the best way to combat powdery mildew is to comply with the rules of agricultural technology. Do not allow overmoistening of the soil and thickening of plantings. Proper care will not eliminate the chance of infection, but will reduce the risk of the disease by 90%.

Chemical treatment of the disease

The most effective drugs used in the fight against powdery mildew are products containing a fungicide. It destroys the structure of the fungus and inhibits its development in plant cells.

The most effective drugs are:

Remember that it is better to prevent the disease than to fight it. Do not allow the progression of the disease and get rid of pathogens in the early stages. Powdery mildew is not terrible to a trained gardener. How to deal with it, he knows for sure.