Author: Elena N. https://floristics.info/ru/index.php?option=com_contact&view=contact&id=19 Category: Plant Diseases Published: October 21, 2016Last edits: July 16, 2020
- Powdery mildew on cucumbers
- Powdery mildew on currants
- Powdery mildew on phlox
Powdery mildew, or ash, or white , is a fungal disease that is caused by microscopic fungi living in the soil from the order Powdery mildew or Erysiphyceae. The disease affects many crops - grapes, roses, gooseberries, grains, peaches, pumpkin crops and sugar beets, but each plant with the same symptoms has its own pathogen. For example, American powdery mildew, which affects gooseberries, peach and roses, is caused by three different spherotes.
Powdery mildew disease - description
The first symptom of powdery mildew is a whitish coating of mycelium, on which drops of moisture appear. Powdery mildew appears on leaves and petioles, young shoots, as well as on fruits and stalks of plants. The leaves and shoots located closer to the ground are infected first, and then the disease gradually covers the entire plant. Upon closer examination, you can see sores in the places where the mycelium is attached; the plant withers and loses its attractiveness, since the fungus takes away its nutrition, and the leaves covered with plaque cannot cope with the process of photosynthesis.
Powdery mildew damage leads to a decrease in the winter hardiness of plants. Cracks form on diseased fruits, into which rot pathogens penetrate during secondary infection. Fungi can become active under the following conditions:
- during the rainy season or at temperatures from 15 to 27 ºC against a background of high air humidity - 60-80%;
- with frequent temperature fluctuations;
- after radical anti-aging pruning;
- with high levels of nitrogen in the soil;
- if the planting is too dense;
- when the watering regime is violated - too frequent moistening of the soil or, conversely, when it regularly dries out.
We will tell you how powdery mildew disease develops, how to combat powdery mildew on different crops, and what preventive measures will help you protect your area from this disease.
- Late blight on potatoes and tomatoes - prevention and treatment with folk remedies and chemistry
Causes
There are many factors contributing to the appearance of European cornflower:
- Cool weather (+ 15-25 degrees), high air humidity 60-80%, rainy season. Weather conditions have the greatest impact on seedlings grown in open ground and on the balcony.
- The soil is saturated with nitrogen.
- The seedlings are planted too densely.
- The humidity regime is disturbed. Excessive or infrequent watering is a sure sign of decreased seedling resistance and the appearance of powdery mildew.
To avoid infection, it is necessary to correct the above-mentioned care and cultivation mistakes.
Powdery mildew - control methods
Treatment of powdery mildew
If you are convinced that your plants have been affected by powdery mildew disease, you need to tear off all yellowed and wilted leaves and flower stalks. Don't be afraid of drastic pruning of the plant - the more diseased parts you cut off, the greater the likelihood that the plant will heal. Treat the affected plant with a fungicide in such a way that the composition generously moistens all its above-ground parts - the treatment solution should drain from the plant like water after a rainstorm. When treating plants in the garden, do not forget to spray the soil in the tree trunk or the soil in the garden bed with fungicide.
What to do with powdery mildew on indoor flowers? If the disease appears on house plants, generously treat the soil in which it grows and the walls of the pot with fungicide. In case of severe damage, remove the top layer of soil with colonies of mushroom mycelium from pots or containers and replace it with fresh, disinfected substrate.
Powdery mildew disease - prevention
The fight against powdery mildew is carried out comprehensively - in addition to chemical treatment of plants, it is necessary to take the following agrotechnical measures:
- water the plants only after the top layer of soil has dried;
- remove and burn all plant debris in the fall;
- observe crop rotation;
- grow varieties and hybrids resistant to powdery mildew;
- do not overfeed plants with nitrogen fertilizers, especially during budding;
- do not forget to apply potassium-phosphorus fertilizers, which increase plant resistance to disease;
- carry out spring sanitary pruning of trees and shrubs;
- carry out preventive treatment of plants with fungicides in early spring and after leaf fall.
Also, for preventive purposes, plants are treated against powdery mildew with chemicals - for example, three or four times pollination with sulfur or three times treatment with copper sulfate, Bordeaux mixture or other preparations of a similar effect.
Common mistakes
Now let's figure out what the most common mistakes are in the fight against powdery mildew.
- No preventive measures are taken. It is much easier to prevent a disease than to deal with its consequences later.
- Removed diseased parts of plants are not destroyed. It is very important to burn diseased plants to destroy the fungus. If this is not done, the pathogen will again move to healthy plants.
- A single or light treatment is carried out. The key to cure is copious spraying with fungicides. Most often, the treatment needs to be repeated 1-2 times to achieve a sustainable effect.
- Diseased fruits are eaten. This may cause poisoning, diarrhea and nausea.
Powdery mildew on vegetables
Powdery mildew on cucumbers
Treatment for powdery mildew of cucumbers can be carried out with folk remedies and fungicides. But the fight against powdery mildew on cucumbers is impossible without preventive measures. Prevention of powdery mildew consists of following the agricultural practices of the crop and treating the beds three times with Quadris in accordance with the instructions.
How to properly grow cucumbers in the garden
But sometimes, despite all your precautions, the disease still manifests itself. How to treat powdery mildew on cucumbers? Measures to combat powdery mildew on cucumbers may include treating the plants with folk remedies or chemicals, but in any case, before spraying, do not forget to remove all parts of the plant affected by the disease. Good results are obtained by dusting cucumbers with sulfur powder at the rate of 25-30 g per 10 m² or treating the beds with a solution of colloidal sulfur at the rate of 25-30 g per bucket of water.
Spraying cucumbers with mullein also helps. If you decide to use fungicides, then Oxychom and Topaz for powdery mildew in accordance with the instructions will be more effective than other drugs.
Powdery mildew on tomatoes
Powdery mildew on tomatoes occurs when there are two types of fungi. One of them, Oidiopsis erysiphoides, is a rare phenomenon in open ground; it more often affects tomatoes in a greenhouse. This usually happens in March if the greenhouse has not been disinfected. The development of the disease can be observed on seedlings - its leaves begin to dry out at the edges, and if you are late with treatment, the seedlings may die. The second causative agent of powdery mildew, Oidiopsis taurica, appears as yellow spots on the upper side of tomato leaves, and a white coating can initially be found only on their underside, but over time it appears on the top.
To the preventative measures against powdery mildew that we have already described, you can add soaking tomato seeds before planting seedlings for 42 hours in a solution of Immunocytophyte or Epin.
How to grow tomatoes correctly - planting and care
But if the defeat does occur, what should you use to spray tomatoes against powdery mildew? It is advisable to treat seedlings with a solution of sodium humate, which completely suppresses the germination of conidia of the causative agent. Spraying is carried out in accordance with the instructions once every two weeks. Biological preparations for powdery mildew do a good job, for example, a one percent solution of Baktofit, which is used to treat tomatoes three times with an interval of 7-10 days, as soon as the first signs of the disease appear.
The fight against powdery mildew on tomatoes is also carried out with the Planriz cultural liquid, which is used when the first signs of the disease are detected. Of the fungicides, the drugs most often used are Strobi, Topaz, Quadris, Tiovit Jet, Bayleton and Privent. For better “adhesion” of the drug to the treated plant parts, add a little silicate glue or laundry soap to the fungicide solution.
Those who avoid using chemical protection products in the fight against plant diseases can treat tomatoes with ten percent whey, skim milk or ash solution for preventive and therapeutic purposes.
Powdery mildew on zucchini
If you find a white coating on your zucchini, cut and burn the affected leaves and shoots and dig up the soil around the infected plant. To destroy the fungus, spray the area with zucchini with a solution of soda ash or cow manure, as well as an ash solution. Among the chemicals used are Kefalon, Carboran and sodium phosphate.
- Orchid roots are rotting and drying out - what to do?
Planting and growing zucchini in the garden
Treatment of zucchini for preventive purposes is carried out in early spring with a Nitrafen solution, and therapeutic spraying with the already listed chemicals is carried out before and after flowering. Plants are sprayed with fungicides at least three times every 7-10 days, and folk remedies should be applied every other day. It is better to spray zucchini in the evening in dry weather.
Powdery mildew on eggplants
You can destroy powdery mildew on eggplants with a solution of soda ash, which we wrote about in the section on zucchini, or with any fungicide, for example, Fundazol (10 g per 10 liters of water). It will take 4-5 treatments at weekly intervals.
Planting and caring for eggplants on the site
Powdery mildew on onions
Onions are affected by downy mildew, or downy mildew. This dangerous disease also develops in conditions of high humidity and low air temperature. The infection is spread by wind or raindrops, as well as plant debris.
Fighting powdery mildew on shrubs and trees
Powdery mildew on currants
Powdery mildew on currants immediately catches the eye, and if you do not fight it immediately, by mid-summer the disease can affect the entire currant tree, and it does not matter which type of currant is affected: powdery mildew on black currants is as harmful as on red or white.
The fight against powdery mildew on currants, as on other plants, is carried out using both folk and chemical means. Treat the plant from all sides, trying to get the medicine not only on the upper side of the leaves, but also on the underside. To do this, you can use a spray bottle or a soft brush. It is better to carry out the procedure in the evening, in dry weather. Sessions are repeated at least once a week for a month.
Control of diseases and pests of currants
Powdery mildew on currants can be cured using folk remedies - dusting with sulfur, spraying with soda ash, ash water, mullein solution, whey, a weak solution of potassium permanganate and other compounds, a more detailed description of which we will give in a separate chapter. Measures to combat powdery mildew on currants in the event of total damage by the disease may include the use of chemicals.
How to treat currants against powdery mildew in this case? Treatment of bushes in the spring with copper sulfate (10 g per 10 liters of water), Nitrafen or iron sulfate (30 g per 10 liters of water) is effective. During the budding period, copper oxychloride (30 g per 10 liters of water) or one percent Bordeaux mixture is used to spray currants, and after flowering, soda ash is used against powdery mildew - two or three treatment sessions with an interval of 10 days.
And don’t forget to remove all plant debris from under the bushes in the fall.
Powdery mildew on gooseberries
Since currants and gooseberries are relatives, the methods of combating powdery mildew on gooseberries are the same as on currants. Folk remedies for processing gooseberries and currants include whey, kefir or curdled milk, mullein, soda ash or baking soda, a decoction of horsetail, tansy, infusions of rotted hay, onion peels, and wood ash. Of the chemical preparations, the most effective in combating disease on currants and gooseberries are solutions of ammonium nitrate, Gaupsin and Trichodermin. By the way, Fitosporin is used against powdery mildew with the same result as against late blight.
Treatment of diseases and pest control of gooseberries
Powdery mildew on grapes
Powdery mildew that affects grapes is called oidium. The primary signs of the disease are the same - a whitish powdery coating on the leaves, shoots, stems and fruits of the plant. Conditions that stimulate the development of the disease are temperatures of 18-25 ºC with high air humidity, but rain, on the contrary, slows down the spread of the disease.
How to fight powdery mildew on grapes? In the hot season, when the air temperature is above 20 ºC, grapes are sprayed with sulfur: for preventive treatment, 25-40 g, and for therapeutic treatment, 80-100 g of sulfur is dissolved in 10 liters of water. In cooler weather, colloidal sulfur or other sulfur preparations are used.
Growing grapes - planting and care
However, during the period of fruit ripening, it is extremely undesirable to use chemicals - you should stop treating grapes with substances that are toxic to humans at least a month before harvest. How to treat grapes against powdery mildew during the period of filling and ripening of berries? Try spraying the plant with a pale pink solution of potassium permanganate - this measure will restrain the development of the disease, and when the harvest is harvested, you can continue treating the grapes with chemicals.
What powdery mildew fungicides can be used to treat grapes? The drugs Quadris, Tiovit Jet and Topaz have proven themselves best in the fight against oidium.
Powdery mildew on an apple tree
Severe development of powdery mildew on apple trees can reduce the yield level by half. In addition, the resistance of trees to cold weather may also suffer. Powdery mildew poses the greatest danger to nurseries because it can quickly spread to trees growing close to each other.
- Why flowers get sick: symptoms and causes
How to get rid of powdery mildew on apple trees and other fruit trees? The most effective way is to treat plants with colloidal sulfur, soda ash and soap, or copper oxychloride every 3-4 days. Topaz is effective against powdery mildew on apple trees, and treatment with this drug for preventive purposes should be started from the very beginning of the growing season, and if signs of the disease are detected, 3-4 treatments will be needed with an interval of 6-12 days.
To prevent the disease from spreading, severely affected leaves and shoots must be removed and burned before treatment.
How to deal with apple tree diseases and pests
Powdery mildew on strawberries
Powdery mildew on strawberries appears as a white coating on the underside of the leaves, causing them to gradually become leathery, and their edges curl and acquire a bronze color. A more severe powdery coating appears on the central leaves and tendrils of strawberries. The berries also become covered with a whitish coating and smell like mold.
To avoid the risk of disease, do not allow strawberries to grow too thick, thin them out and plant them in a timely manner. As a treatment for powdery mildew on strawberries, the bushes are treated with a one percent suspension of colloidal sulfur or TMTD, as well as with the preparations Switch, Bayleton, Quadris, or Fundazol after flowering and after harvesting. When processing, try to ensure that the drug gets not only on the top, but also on the underside of the leaves.
How to treat strawberries against diseases and pests
Advantages and disadvantages
Chemical processing methods have more disadvantages than advantages:
- phytotoxicity (plant growth is inhibited);
- the ovary may fall off;
- decreased immunity in plants to pathogens;
- environmental pollution;
- possible negative consequences resulting from contact with various elements in the soil;
- destroy useful ethnofauna;
- after a few years, pests develop resistance to fungicides and become resistant to subsequent treatments;
- Poor effects on pollinating insects.
There is only one advantage, but a significant one: the drugs quickly and efficiently eliminate the source of the disease and prevent its reappearance for the entire season.
Powdery mildew on flowers (garden)
Powdery mildew on phlox
Powdery mildew damages not only vegetables, berries, fruits, fruit trees and shrubs, but also garden flowers. For example, in mid-summer, a white coating may appear on the leaves and stems of phlox, which gradually darkens and becomes dirty brown. This does not add decorative value to the flowers.
Planting and caring for phlox in the garden
How to get rid of powdery mildew on phlox? Diseased leaves and severely affected plants should be destroyed, and the rest should be treated several times at weekly intervals with a one percent solution of colloidal sulfur. For preventive purposes, flower beds are mulched with humus or peat, and in early spring, when the shoots rise to a height of 10 cm, the phloxes are triple treated with an interval of 12-14 days with one percent Bordeaux mixture. To increase the resistance of flowers to powdery mildew, feed them with complete mineral fertilizer.
Powdery mildew on roses
Due to powdery mildew, any flowers, including roses, can lose their decorative properties. With severe damage, rose leaves curl, dry out and fall off prematurely, and bare branches become covered with a felt coating, which does not allow them to grow and develop. To prevent fungus from appearing on roses, keep the soil around the bushes clean and remove weeds. In the fall, after leaf fall and sanitary pruning, rake and burn all plant debris, and dig up the soil under the bushes.
Growing roses in the garden - planting and care
At the first symptoms of powdery mildew, start treating roses with colloidal sulfur, Fundazol, Fitosporin-M or Maxim. Powdery mildew in autumn and early spring is destroyed with the following composition: 15 g of copper oxychloride, 300 g of green soap and 50 g of soda ash are dissolved in 10 liters of water.
Powdery mildew on petunia
Powdery mildew and petunia are affected: a white coating forms on the plants, spreading over all ground organs. As a result of the development of the disease, the petunia begins to rot and die. To cure the plant, it is necessary to remove and burn all infected areas, and then thoroughly treat the petunias with a fungicide - Topaz, Skor, Fundazol, Previkur.
If petunias grow in pots or containers, you need to remove the top layer of soil from them and replace it with soil treated against powdery mildew with Fitosporin-M. Among the folk remedies for combating powdery mildew, soda-soap and ash sprays, as well as treating flowers with whey, potassium permanganate, garlic infusion and mustard solution have proven themselves well.
Planting and caring for petunia in the garden
Powdery mildew on violets
In viola, or garden violet, powdery mildew affects the buds, leaves and stems. Most often this happens in dry sunny weather with heavy morning dew or due to excess nitrogen fertilizers in the soil. Infection with the disease leads to the loss of the plant's decorative properties and a reduction in flowering time. To treat powdery mildew, treat with solutions of Topsin-M, Fundazol, Morestan, Fthalan, Kuprozan, Zineb or soda ash with soap.
Growing viola - planting and care in the garden
How to recognize and what provokes it?
If you notice a gray-white coating that can be mistaken for dust and can be easily removed with a finger, but which reappears after a few days and covers even more surface area, you are dealing with downy mildew. Upon very careful examination, you will notice that ulcers have formed on the affected area. The stem and shoots of the flower will soon turn white, acquire a yellow tint and lose elasticity. The new ones become ugly and curled.
What causes this? The white coating, which resembles flour or mold, is a fungus that feeds on nutrients in the host's body. Its spores are dark brown balls.
The causative agents are different types of imperfect fungi, such as:
- Walrus sphaerotheca attacks gooseberry. Bacteria attack not only leaves, but also berries. The sphaerotheca walrus quickly moves from one bush to another.
- Sphaerotheca fuliginea - pumpkin. The yield of this crop is reduced by 50 percent. The quality of pumpkin and zucchini is also deteriorating.
- Threat to cereals - Erysiphe graminis.
- Sphaerotheca pannosa - roses. The bush loses its decorative appearance. Leaves and buds stop growing. Wormwood can cause the death of a plant.
If the infection is not controlled, the shoots can become completely infected and even die.
Downy mildew appears in early summer. When spores are released from the overwintered fungus, infection begins. Spores can live in the soil for a long time and begin to reproduce under favorable weather conditions.
Powdery mildew on indoor plants
At home, plants such as begonia, cissus, saintpaulia, gerbera, rose and kalanchoe can also suffer from powdery mildew. The cause of the disease is stale, humid air, dry substrate and differences in night and day temperatures. Pathogens are transferred from a diseased plant to a healthy one by insects, air flow, or by contact if the pots are too crowded.
Signs of the disease (white powdery spots) appear on the buds and on both sides of the leaves, and as soon as you find them, immediately begin to destroy the fungus: powdery mildew on plants in the apartment, if delayed with its treatment, leads to sad consequences - loss of attractiveness and rotting.
To destroy powdery mildew pathogens, a solution of soda ash, potassium permanganate or garlic infusion is used, and in case of severe damage, they resort to treating indoor plants with fungicides such as Skor, Hom, Vectra, Bayleton, Fundazol, Vitaros, Topaz or Tiovit Jet. Solutions are prepared strictly according to the instructions.
As a preventive measure, one can consider adding potassium-phosphorus fertilizers to the soil, maintaining water balance and plant hygiene, as well as regular ventilation of the room.
Answers to frequently asked questions
And in conclusion, a small FAQ on the topic of today's article.
Which drug is most effective against powdery mildew?
Topaz has proven itself well.
What can be done to prevent plants from getting sick?
Carry out prevention and do not disdain agricultural practices. Be sure to disinfect the soil.
How many times should plants be sprayed?
Depends on the product you are using.
How to treat diseased fruits?
Either with means prepared according to folk recipes, or with biological products.
Powdery mildew remedies (preparations)
In the fight against fungal diseases, such as powdery mildew, the following chemical fungicides are most often used: Skor, Quadris, Hom, Vectra, Tiovit Jet, Fundazim, Fundazol, Vitaros, Bayleton, Fthalan, Tsineb, Kuprozan, Topsin-M, Fitosporin -M, Previkur, Switch, Bordeaux mixture, copper sulfate, copper oxychloride, colloidal sulfur and others. These drugs are sold in specialized stores and are used strictly in accordance with the instructions.
Treatment of indoor plants with fungicides is carried out outdoors in compliance with safety precautions. Fruit trees, shrubs, vegetables and berries are treated with fungicides only in cases of severe damage, but when the plants enter the fruit growth phase, fungicide treatment should be stopped. In case of minor fungal infection, it is better to treat plants with folk remedies.
How to use fungicides and biofungicides?
Timely and correct use of poisonous agents against ash burns is effective. Chemicals are available in specialized stores and their prices are quite low. Sprayers are used for convenience. When working, it is recommended to take precautions: carry out the procedure in a respirator and gloves.
The most commonly used fungicides are:
- Copper sulfate. Only one treatment per season is possible - in early spring. To prepare the mixture, 50 g of the substance is diluted in 10 liters of water. To prepare the most effective product, add 35 g of copper sulfate to 500 ml of boiling water, and separately mix 150-200 g of soap shavings in 10 liters. Then slowly and carefully pour the resulting liquid into the soap base, stirring constantly. .
- Tiovid Jet. Purchased for the treatment of pears, apples, cucumbers, grapes.
- Fondazol. Unfortunately, it is not sold in small packages, available in bags ranging from 5 to 20 kg. It is recommended to dig up the soil, especially if violets are infected.
- Topaz. Produced for the prevention and control of powdery mildew.
- Colloidal sulfur. Suitable for use in a variety of crops, shrubs and trees. The special difference between this fungicide and others is that it can be sprayed 3 days before harvest. However, it is not recommended to spray gooseberries with sulfur. Be careful on watermelons, zucchini, melons, cucumbers and pumpkins, because these plants do not tolerate sulfur well. Spray strictly at + 27-32 degrees, otherwise it will not work.
- Also popular are Zato, Forecast, Topsin-M, Tilt and Quadris.
Biofungicides contain live bacteria that can prevent the development of infections that accumulate on plants.
Biofungicides are environmentally friendly, so they can be used even during the ripening of crops. They are less effective than chemical drugs because they do not last long. They need to be used again and again. The most commonly used are phytosporin, pseudobacterin-2 and Alirin-B.
Folk remedies for combating powdery mildew
There are many folk remedies for powdery mildew that are safe for humans and plants. For example:
- soap-soda solution: dissolve 50 g of soda ash or baking soda and 20 g of liquid or grated soap in 10 liters of water and treat the plants at least twice at intervals of a week;
- whey solution: pour 1 liter of whey into 10 liters of water, stir and apply three times in dry weather with an interval of 3 days;
- kefir solution: stir 1 liter of fermented kefir or yogurt in 10 liters of water and treat the plants three times with an interval of three days;
- horsetail decoction: pour 100 g of horsetail with one liter of water, leave for 24 hours, simmer for two hours over low heat, cool, strain, dilute with water 1:5 and carry out 3-4 treatments at intervals of five days. Undiluted, the decoction is stored in a cool, dark place for about a week;
- mustard solution: dilute 2 tablespoons of mustard powder in 10 liters of warm water and spray or water the plants;
- potassium permanganate solution: dissolve 5 g of potassium permanganate in 10 liters of water. This solution stops the development of the disease and washes away the fungus from the fruit;
- ash solution: add 1 kg of wood ash to 10 liters of water, stir, leave for 7 days, carefully drain, dissolve 20 g of liquid or grated soap in the infusion and treat the plants with this composition every other day;
- mullein infusion: one part of cow manure is poured with three parts of water and infused for at least three days, then the infusion is carefully drained, the same amount of water is added to it and the treatment is carried out before flowering, after it and before leaf fall;
- garlic infusion: 50 g of garlic pulp (crushed cloves and shoots of garlic) are poured with two liters of water, infused for two days and filtered. Use the infusion undiluted;
- infusion of onion peels: 200 g of onion peels are poured into 10 liters of boiling water, infused for two days, filtered and sprayed on the plants before flowering, after it and before leaf fall.
