But each plant with the same symptoms has its own pathogen. For example, American powdery mildew, which affects gooseberries, peaches and roses, is caused by three different sphere libraries.

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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 the fruits and stalks of plants. Leaves and shoots located closer to the ground are infected first, and then the disease gradually covers the entire plant. On closer examination, one can see ulcers in the places of attachment of the mycelium, the plant withers and loses its attractiveness, since the fungus takes away its nutrition, and the leaves covered with bloom cannot cope with the process of photosynthesis. Defeat from powdery mildew leads to a decrease in winter hardiness of plants. Cracks form on diseased fruits, into which rot pathogens penetrate during secondary infection. Active fungi can become under such conditions:

• in the rainy season or at temperatures from 15 to 27 ºC against the background of high humidity - 60-80%;
• with frequent temperature fluctuations;
• after radical anti-aging pruning;
• at high level nitrogen in the soil;
• with too dense landing;
• in case of violation of the irrigation regime - too frequent wetting of the soil or, conversely, with its regular drying out.

We will tell you how powdery mildew develops, how to deal with powdery mildew on different crops, and what preventive measures will help you protect your site from this disease.

Powdery mildew - control methods

If you are convinced that your plants are affected by powdery mildew disease, you need to cut off all yellowed and wilted leaves and flower stalks. Do not be afraid to drastically cut the plant - the more diseased parts you cut, the more likely the plant will heal. Treat the affected plant with a fungicide in such a way that the composition abundantly moistens all its ground parts - the medicinal solution should drain from the plant like water after a downpour. When treating plants in the garden, do not forget to spray the soil in the trunk circle or the soil in the garden with a fungicide.

What to do with powdery mildew on indoor plants? If the disease has manifested itself on house plants, treat the soil in which it grows and the walls of the pot abundantly with the fungicide. For severe infestation, remove from pots or containers upper layer soil with colonies of mushroom mycelium and replace it with a fresh, disinfected substrate.

Powdery mildew disease - prevention

The fight against powdery mildew is carried out in a complex way - in addition to the chemical treatment of plants, it is necessary to take the following agrotechnical measures:

• water the plants only after the topsoil dries;
• remove and burn all plant residues in the fall;
• observe crop rotation;
• grow powdery mildew-resistant varieties and hybrids;
• do not overfeed plants with nitrogen fertilizers, especially during the budding period;
• do not forget to apply potassium-phosphorus fertilizers that increase the resistance of plants to the disease;
• carry out spring sanitary pruning of trees and shrubs;
• preventive treatment of plants with fungicides in early spring and after leaf fall.

Also, for preventive purposes, powdery mildew treatment of plants is carried out. chemicals- for example, three or four times pollination with sulfur or three times treatment with copper sulphate, Bordeaux liquid or other preparations of a similar effect.

Powdery mildew on vegetables

Powdery mildew on cucumbers

Treatment for powdery mildew of cucumbers can be carried out folk remedies and fungicides. But the fight against powdery mildew on cucumbers is impossible without preventive measures. Powdery mildew prevention consists in observing the agricultural practices of the culture and treating the beds three times with Quadris in accordance with the instructions.

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 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 Oxyhom and Topaz from powdery mildew in accordance with the instructions will be more effective than other drugs.

Powdery mildew on tomatoes

powdery mildew on tomatoes occurs when two types of fungi are affected. One of them, Oidiopsis erysiphoides, open ground- a rare phenomenon, it often affects tomatoes in a greenhouse. This happens, as a rule, in March, if the greenhouse was not disinfected. The development of the disease can be observed on seedlings - its leaves begin to dry out from the edges, and if you are late with treatment, then the seedlings may die. The second causative agent of powdery mildew, Oidiopsis taurica, appears as yellow spots on the upper side of the tomato leaves, and a white coating can first be found only on their underside, but over time it appears on top.

to the already described preventive measures against powdery mildew, you can add soaking tomato seeds before planting on seedlings for 42 hours in a solution of Immunocytophyte or Epin.

But if the defeat did happen, how to spray tomatoes from powdery mildew? It is advisable to treat seedlings with a solution of sodium humate, which completely inhibits the germination of conidia of the pathogen. 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 Bactofit, 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, Strobi, Topaz, Quadris, Thiovit Jet, Bayleton and Prvent are most often used. For better "stickiness" of the drug to the treated parts of plants, a little silicate glue or laundry soap is added to the fungicide solution.

Those who avoid using chemical protection agents in the fight against plant diseases can use the treatment of tomatoes with ten percent whey, skim water or ash solution for preventive and therapeutic purposes.

Powdery mildew on squash

If you find a white coating on the squash, cut and burn the affected leaves and shoots and dig up the soil around the infected plant. To destroy the fungus, spraying the area with zucchini with a solution of soda ash or cow dung, as well as ash solution. Of the chemicals used Kefalon, Carborane and sodium phosphate.

Treatment of zucchini for preventive purposes is carried out in early spring with a solution of Nitrafen, and therapeutic spraying with the chemicals already listed - before and after flowering. Plants are sprayed with fungicides at least three times after 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 eggplant

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.

Powdery mildew on onions

Onions are affected by downy mildew, or downy mildew. This dangerous disease also develops under high humidity and low air temperature. The infection is carried by the wind or with raindrops, as well as with plant debris.

Powdery mildew control on shrubs and trees

Powdery mildew on currants

Powdery mildew on currants immediately catches the eye, and if you do not immediately fight it, by mid-summer the disease can affect the entire currant, and it does not matter which type of currant is affected: powdery mildew on blackcurrant is just as harmful as on red or white. The fight against powdery mildew on currants, as well as on other plants, is carried out by both folk and chemical means. The plant is treated from all sides, trying to ensure that the medicine is not only on the upper side of the leaves, but also on the bottom. To do this, you can use a spray gun or a soft brush. The procedure is best done in the evening, in dry weather. Sessions are repeated at least once a week for a month.

You can cure powdery mildew on currants with folk remedies - dusting with sulfur, spraying with soda ash, ash water, mullein solution, whey, a weak solution of potassium permanganate and other compounds, more detailed description which we will give in a separate chapter. Measures to combat powdery mildew on currants in the event of a total defeat by the disease may include the use of chemicals. How to treat currants from powdery mildew in this case? Effective treatment of bushes in the spring with copper sulfate (10 g per 10 l of water), Nitrafen or ferrous sulfate (30 g per 10 l of water). During the budding period, copper oxychloride (30 g per 10 l of water) or one percent Bordeaux liquid is used to spray currants, and after flowering, soda ash from powdery mildew is used - two to three treatment sessions with an interval of 10 days.

And do not forget to remove all plant debris from under the bushes in the fall.

Downy mildew of hops. The causative agent is a pseudofungus of the Oomysta class Pseudoperonospora humuli Wilson.

The pathogen overwinters in the form of mycelium in the buds of plants, so the disease manifests itself already in early spring. Young shoots are thin, deformed, with shortened internodes, small chlorotic twisted leaves. The leaves are covered on the underside with a greenish-brown bloom of sporulation. Often the affected shoots become spike-shaped. Later, the disease manifests itself in the form of yellow-green spots limited by veins, which quickly necrotic. The infected parts of the flowers are underdeveloped and dry out. Integumentary leaves on fully formed cones acquire a brown-red color. At high humidity, all affected organs of plants are covered with bloom. Red-brown areas may appear on the roots, mottled with dark brown necrotic spotting.

The pathogen forms a highly branched unicellular mycelium. Conidiophores are strongly branched, formed in bundles, at the ends of which unicellular lemon-shaped conidia are formed. They provide re-infection of plants during the growing season. In all affected tissues, spherical light brown oospores with a smooth thick shell are formed, which are the main source of primary infection.

Downy mildew is strongly manifested in cool and humid weather, fogs. The optimal temperature for pathogen development is +20...+22°C, relative humidity is 90-100%, and therefore the disease has two maxima in its development - in spring and autumn.

Powdery mildew of hops. The causative agent is a fungus of the class Fruity, or Euascomycetes, Sphaerotheca macularis P. Magn. f. sp. humuli Lev. (theliomorph); conidial stage (anamorph) Oidium jragariae Harz. This disease has a small distribution and is more common in low-growing stands. In the kidneys of the mother plant is the mycelium of the fungus. Shoots develop weak, with small leaves. In summer, powdery mildew manifests itself in the form of growing powdery raids covering the vegetative and generative organs of plants. At the end of the growing season, small black dots appear on the powdery coating - fungus cleistothecia.

They are spherical, contain 1 ascus (bag) with 8 unicellular ellipsoidal ascospores. Conidiophores are simple, on their top there are chains of ovoid unicellular thin-walled conidia.

Verticillium wilt of hops. The causative agent is a fungus of the class Hyphomycetes Verticillium albo-atrum Rke et Berch. Single spots of light green color develop on the leaves. Leaves first wither and then dry up. These signs may appear on individual shoots or on the entire plant. Bottom part the stem turns brown, more often the lesion is observed at a height of 10-30 cm from the ground. On the transverse section of the stem, it can be seen that the wood of the affected plants acquires a green-brown color. The causative agent infects the roots of plants directly or in places of damage.

The fungus forms characteristic erect, whorled branched conidiophores, on which unicellular small conidia are formed, which are of little importance as a source of secondary infection.

A pathogen is a typical soil-dwelling species that can develop saprotrophically in the soil, remaining in it and on plant debris more often in the form of microsclerotia. The fungus has many cultivated and wild hosts belonging to various botanical families.

The disease is more pronounced on plants cultivated on light sandy soils with a neutral or alkaline reaction of the soil solution. The optimal temperature for pathogen development is +20…+23°C.

The disease spreads with the help of infected cuttings, the main source of primary infection is also infected soil.

Plenodomus (root) hop rot. The causative agent is a fungus of the class Coelomycetes Plenodomus humuli Kusnetz.

The disease develops on heavy loamy soils with high acidity. Brown depressed spots appear on the underground parts of the stem and adjacent roots of the mother plant. Large (up to 1 mm) black pycnidia with thick walls are clearly visible on their surface. The spots grow, the root rots. With severe damage, the plant dies. Sometimes 1-2 stems die, but the rest give a reduced yield.

The main source of infection are plant residues in the soil. The pathogen enters the plant through damage. Especially strong infection is noted in the spring or autumn.

bacterial cancer. The causative agent is the bacteria Agrobacterium rhizogenes Riker et al. (syn. A. tumefaciens Conn). It affects the underground parts of hop plants, on which tumors of two types are formed:

1) tumors of various shapes and sizes (from a pea to a large chicken egg) without additional roots;

2) small tumors with a large number of flat thin additional roots.

Initially, there is a rapid growth of hops, then - its oppression. Tumors rot, the rhizomes of mother plants are destroyed, which leads to death. The disease is usually focal in nature.

The development of the disease is facilitated by a relative soil moisture of 60-80% and a temperature of about 18°C. Bacteria enter the plant through damage to underground parts. The main source of infection is growths that remain in the soil.

Mosaic of hops. The causative agent is the Hop mosaic virus, belongs to the Carlavirus group and has filamentous virions. A very common disease of this crop leads to a decrease in yield.

Symptoms of the disease vary greatly depending on the susceptibility of genotypes. Some varieties have a large mosaic of leaves, while others have a lightening of the veins and leaves or a weak manifestation of mosaic. In a third group of very susceptible cultivars, the internodes on the top of the stems are severely shortened and become hard so that they cannot curl around the support. Lateral shoots are poorly developed, do not form peduncles, form very deformed cones. root system gradually dies off, and after 2-3 years the plant dies. There is a group of varieties that are tolerant to mosaic, the plants on the leaves do not have its symptoms. Only the middle lobe of the leaf is elongated and characteristically twisted.

The virus spreads from diseased plants to healthy ones with the help of several types of aphids: Phorogon humuil, Macrosiphum euphorbiae and Aphis fabae. The development of the disease depends very much on the dynamics of the summer of aphid species that carry the virus.

Chlorotic Mosaic and Necrotic Hop Curl. The Primus necrotic ringspot virus belongs to the Ilarvirus group and has isometric virions. It revealed two strains that cause respectively chlorotic and necrotic forms of the disease. Chlorotic mosaic and necrotic curl are common and harmful hop diseases. The first signs of damage vary greatly depending on the variety of strains, meteorological conditions and resistance of varieties, but can be grouped into two main types:

1. Chlorotic mosaic appears as yellow-green rings and stripes on lower leaves, gradually covering the side shoots, including the integumentary leaves of the cones. With summer warming, the symptoms become latent, appearing again in the fall. Plant growth is suppressed. Fruiting shoots are short, with a small number of non-standard loose cones.

2. Necrotic curl varies from slightly mosaic deformity and asymmetry to twisting of the leaf along the midrib followed by necrosis. In some varieties, the leaf blades have serrated edges and a strong dissection. The last internodes of plants are very shortened, and the apex is necrotic. From the lateral buds, new shoots appear that cannot curl around the supports. A few years after infection, the plants die.

The virus can be transmitted by vaccination and pollen, sometimes it is possible to spread the pathogen with seeds. New plantations should be planted with healthy planting material.

Arabis Mosaic, Rezuhi Mosaic on Hops. Rezuhi mosaic virus (Arabis mosaic virus) from the Nepovirus group, has isometric virions. Depending on the diversity of strains and the susceptibility of varieties, two types of manifestation of the disease are observed,

1. Nettiness of leaves is characterized by stunted growth of the main shoots, which cease to curl near the support. Leaves shrink, dissection leaf blades disappears, they become solid, their tops lengthen, and in general become similar to nettle leaves. The underside of the leaves becomes greenish, and the veins swell. The upper part of the shoots gradually necrotic. Some shoots are very affected, others look healthy and develop normally. In plantation, the disease develops relatively slowly.

2. In some varieties, leaf rupture is observed. It appears as a yellowish oily blotch followed by rupture of the leaf blade. Diseased plants form several underdeveloped dark green or reddish shoots. The general growth and development of plants are suppressed.

With a mixed infection of arabis mosaic with chlorotic mosaic and necrotic curl, signs of virus damage are more pronounced. The virus spreads during vaccination and nematodes Xiphinema index and X. diversicadatum.

Symptoms and treatment of powdery mildew on currants

Powdery mildew is a common fungal disease of fruit and berry crops. If you do not take up treatment in time, then you can lose not only the seasonal crop, but also the plant as a whole. Powdery mildew on currants has its own characteristic features. Treatment of the disease is possible folk ways and with the help of special chemicals.

Causes and signs of development of powdery mildew

On currants, powdery mildew develops from microscopic spore fungi that are found in the soil or carried by the wind. With the same symptoms, each plant has its own powdery mildew pathogen. In other words, a disease that has developed on cucumbers cannot infect gooseberries or cherries.

Source: Depositphotos

Leaf curl is the first sign of powdery mildew on currants.

Infection occurs in mid-spring or early summer. After the onset of hot and humid weather, the spores burst, the disease begins to develop actively and completely infects the plant in just 2 months. The characteristic signs of powdery mildew are:

• blanching, twisting and covering the leaves with a white coating that is not erased by mechanical action;
• slowdown or complete cessation of the growth of the bush;
• coating of formed berries with bloom, shedding of young fruits;
• drying of shoots.

Powdery mildew significantly reduces the frost resistance of plants. If measures are not taken in time, the currant may die not from the disease itself, but from the upcoming frosts.

How to deal with powdery mildew on currants

For the treatment and prevention of disease, there are folk recipes and specialized chemicals. In both cases, spray the shrub with a spray gun from the bottom up. If there is no such device, use a soft brush. Process currants in the evening in dry weather.

If the disease is detected at the initial stages, the following means are suitable for treatment:

• a solution of 25 g of soda ash per 5 liters of water;
• 1 kg of sifted wood ash and a grated bar of laundry soap mixed in 10 liters of water;
• a solution of potassium permanganate at the rate of 3 g of the substance per 10 l;
• 3 liters of whey diluted in 7 liters of water with the addition of a teaspoon of copper sulfate.

In the later stages, the shrub can only be cured with special chemicals. The most popular are "Fundizol", "Topaz" and "Vitaros". A solution of copper or iron sulphate at the rate of 30 g per 10 liters of water has proven itself well.

Powdery mildew develops very quickly on all types of currants. After identifying the first signs, treat the bush as soon as possible, do not forget to remove fallen leaves for the winter, in which fungus spores may be hiding.

English mildew of hop; powdery mildew of hop; red mold of hop

German Hopfenschimmel; Mehltau, Hopfen

French blanc du houblon; oidium du houblon

• - peronosporosis, a disease of districts caused by fungi class. phycomycetes family. peronospore...
• - ashtray, white, district diseases caused by powdery mildew fungi. Many strike. s.-x. culture...

  Agricultural Encyclopedic Dictionary

• - see Powdery mildew ....
• - a white cobweb fungal coating on the surface of leaves, shoots, fruits of many plants, has a powdery appearance from the accumulation of a mass of spores, to which the fungus multiplies ...

  Agricultural dictionary-reference book

• - English. downy mildew; false mildew germ. falscher Mehltau French...
• - English. mildew; powdery mildew Mehltau French. blank...

  Phytopathological dictionary-reference book

• - English. mildew of rye; powdery mildew of rye Mehltau, Roggen fr. blanc du seigle...

  Phytopathological dictionary-reference book

• - English. powdery mildew of soja bean Mehltau, Sojabohne French blanc du soja...

  Phytopathological dictionary-reference book

• - a disease of plants caused by marsupial fungi from the family. Erysiphaceae and so named because of appearance the upper surface of the leaves of a plant affected by a fungus, covered with a white dressing of powdery mycelium and ...

  Glossary of botanical terms

• - diseases of districts caused by powdery mildew fungi. Many strike. s.-x. crops, trees. On leaves, stems, fruits - a powdery-white powdery coating, the fruits crack and rot ...

  Natural science. encyclopedic Dictionary

• - a white powdery or moldy coating formed on different kind plants with fungi from the family. Erysiphea. The leaves of adult plants from M. dew covering their upper side turn yellow, turn brown and die ...

  Encyclopedic Dictionary of Brockhaus and Euphron

• - fungal gooseberry disease, see Mealy ...
• - ash, white, a group of plant diseases caused by powdery mildew fungi ...

  Great Soviet Encyclopedia

• - plant diseases caused by powdery mildew fungi. Many agricultural crops, tree species are affected ...

  Big encyclopedic dictionary

• - noun, number of synonyms: 2 ashtray disease ...

  Synonym dictionary

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