How to get rid of powdery mildew? care

Unfortunately, many gardeners are well aware of this plant disease – powdery mildew. It is found on garden trees and shrubs, on vegetable crops (cucumbers, squash, squash), as well as on many flowers, even indoor ones. Today, all methods of combating powdery mildew can be conditionally divided into three groups: the use of fungicides, biofungicides and folk remedies. Read about each of these methods in this article. And we will also talk about the prevention of powdery mildew on garden and indoor plants.

Powdery mildew on pumpkin leaves. Farmer Scot Nelson


What is powdery mildew?

Powdery mildew is a fungal disease of plants, caused by various types of microscopic fungi – parasites. On the surface of the leaves of the affected plant, a white coating of mycelium appears, on which drops of liquid form after the spores mature. Hence the name “powdery mildew”. The mycelium is located in spots, most often on the leaves and young shoots, but also on the petioles, stalks and fruits. Infection usually begins with leaves closer to the ground and gradually spreads to the entire plant. Fruit infestation leads to cracking and decay.

Looks like: Powdery mildew can be recognized by its grayish white coating or by the characteristic dark brown balls on the surface of leaves and young stems. Over time, the plaque becomes denser and then turns brown.

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What caused: Powdery mildew is a mycelium that lives off the plant. The dark brown balls are her spores.

Pathogens: The name of the disease reflects the description of the symptoms of infection common to different species of different imperfect fungi. For example:

  • Uncinula necator – causes powdery mildew on the vine;
  • Sphaerotheca mors – on gooseberries;
  • Erysiphe graminis – on grain crops;
  • Sphaerotheca pannosa forma persicae – on a peach;
  • Erysiphe communis – on sugar beets;
  • Sphaerotheca pannosa Lew. var. rosae Voron. – on the rose;
  • Erysiphe cichoracearum, Sphaerotheca fuliginea – on pumpkin seeds.

Why is it dangerous: Plants lose their decorative appearance. Severely affected parts of plants stop growing, turn black and die off. Diseased inflorescences do not form ovaries. Even, it would seem, not a strong defeat leads to a sharp decrease in winter hardiness in shoots and buds, and as a result – their freezing.

Powdery mildew on tomato leavesPowdery mildew on tomato leaves. Farmer Scot Nelson

When appears: Infection begins in early summer when the spores are released from the fruiting body of the overwintered fungus.

What contributes to: Powdery mildew develops in hot dry seasons with sharp fluctuations in temperature and humidity. Sometimes after excessive application of nitrogen fertilizers, after strong rejuvenating pruning, which significantly reduces the resistance of the plants.

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How it spreads: By wind or water spray when watering. In direct contact with a plant of the same species.

The disease develops especially strongly in dry hot weather with sharp fluctuations in temperature and humidity. Under such conditions, the turgor (tension of cell membranes) state of plants is noticeably reduced. And this enhances the development of the parasite, which easily invades them, piercing the integumentary cells.

Vegetable crops of the pumpkin family, suffering from powdery mildew, very often lose 50% in the yield, and the quality of the fruits also decreases. It should be noted that cucumbers grown in greenhouses are more affected by disease in drafts, poor lighting, when the physiological state of plants deteriorates. As a result, the resistance of the cucumber against the disease decreases. As a rule, the first foci appear near doors and vents. Whole lashes die from the disease, and all planted plants can die within a short time.

Powdery mildew on begoniasPowdery mildew on begonias. Farmer Scot Nelson

Prevention and methods of dealing with powdery mildew

It is important to take control measures on time, being late threatens to spread the infection over large areas. Since the villainous mushroom hibernates on plant debris, the first and necessary measure to combat powdery mildew is cleaning and burning plant waste, crop rotation. Use of resistant and slightly affected plant hybrids.

Overfeeding plants with nitrogenous fertilizers, especially during the budding period, increases the risk of powdery mildew disease. On the contrary, feeding with phosphorus and potash fertilizers increases resistance to the pathogen of powdery mildew.

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The appearance of the disease on currants and gooseberries causes curvature of the shoots, which lag behind in growth, the leaves become small, ugly and, after a while, dry out. On the gooseberry, in addition to shoots, fruits are also affected, first white, and then darkening spots are formed on them. They stop growing, shrivel and may fall off.

The development of the disease is facilitated not only by humid hot weather, but also by excessive application of nitrogen fertilizers, strong anti-aging pruning, which significantly reduces the resistance of plants.

An important condition for fighting the disease is spring tenderloin of affected shoot ends on gooseberries and currants… Feeding with phosphorus and organic fertilizers is also effective. In the periods before flowering and after harvesting the fruits, plants need to be treated with fungicides.

On the apple tree leaves, flowers, young shoots are affected. Leaves stop growing, curl and fall off. Affected shoots and buds freeze out in winter, and the winter hardiness of trees is sharply reduced. Powdery mildew is more pronounced on old trees, in neglected, uncut gardens, on plants located on the southern and southwestern slopes.

In strawberries, raspberries, rose hips, all aboveground organs become ill, more often leaves that coarse, their edges curl in the form of a boat, exposing the lower side, which eventually acquires a bronze tint. In late summer – early autumn, such leaves are especially noticeable. A weak powdery bloom forms on the berries, and they acquire a specific mushroom smell.

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In flowers, leaves affected by powdery mildew darken and fall off.

On trees, it is necessary to cut out the affected shoots in a timely manner and carry out the treatment with fungicides in the phases of extension and separation of the buds.

Brown apple due to powdery mildewBrown apple due to powdery mildew. Farmer Alan Biggs

Use of fungicides

Chemical measures to combat powdery mildew with their timely and correct application are quite effective.

Fungicides (fungus – fungus and caedo – kill) are chemicals used to fight fungal plant diseases.

Of the modern fungicides against powdery mildew, it is worth noting drugs: Bayleton, But, Quadris, Raek, Skor, Tilt, Topaz, Topsin, Tiovit Jet, Fundazim, Fundazol.

Cases of the emergence of resistant races of the fungus to chemical preparations on some crops have been noted, therefore, the breeding of varieties resistant to powdery mildew is an extremely urgent issue.

Use of biofungicides against powdery mildew

Biofungicides are biological products that are designed to protect plants from fungal diseases. They include live bacterial cultures that suppress the growth of pathogenic fungi.

Due to the fact that biofungicides are environmentally friendly, they can be used even during the period of fruit ripening. In terms of effectiveness, they are inferior to chemical preparations, and their effect is limited in time. They are used many times.

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The most famous biofungicides against powdery mildew: Fitosporin-M, Alirin-B, Gamair, Pseudobacterin-2, Planriz.

Powdery mildew on cabbage leavesPowdery mildew on cabbage leaves. Farmer Scot Nelson

Folk remedies against powdery mildew

1st recipe: Dissolve 4 grams of soda ash in 1 liter of water, add 4 grams of soap. Stir thoroughly and spray the plants 2 times at weekly intervals.

2st recipe: Pour 0,5 cups of ash with 1 liter of boiling water, leave for 2 days, strain, add 4 grams of soap, previously diluted in water. Process twice with an interval of 7 days. With severe damage, there may be more treatments.

3st recipe: Fresh mullein. To prepare the product, it is necessary to pour 1/3 of a bucket of fresh manure with cold water and leave for 3 days, stirring occasionally. Then filter through a thick cloth and dilute with water in a ratio of 1:10. Plants should be sprayed in the evening to avoid sunburn. A fresh infusion is prepared before each treatment.

4st recipe: Fermented water. To combat powdery mildew, you can use any garden weeds, with their help, the so-called fermented grass is prepared. To do this, pour 1/2 bucket of finely chopped weeds to the top with hot water, stir and leave for several days, then strain through cheesecloth. Spray in the evening.

5st recipe: Sour milk or kefir (yogurt). The preparation for spraying is prepared from the separated fermented milk whey, it is diluted in a ratio of 1:10 with cold water and stirred until a homogeneous solution is obtained. The prepared solution is poured into a sprayer and the plants are treated.

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We hope that the methods described above for controlling powdery mildew will help you fight this unpleasant plant disease. But remember that the best way to fight any disease is prevention.

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Anna Evans

Author ✓ Farmer

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