Fruit trees

Powdery mildew on apple

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The most common tree in the gardens of gardeners and gardeners is an apple tree. Her love for the taste and benefit of fruits that are rich in vitamins and fiber, necessary for the functioning of the human body. But what to do if in one of the seasons a white bloom appeared on the leaves of the apple tree? It is very important not to miss this moment, since the plaque is the first stage of the disease of the tree called powdery mildew.

Mealy dew: description and reasons

Mealy dew is one of the most serious diseases of the tree, which affects all organs: leaves, young shoots, inflorescences. In the later stages, in the absence of measures to combat the disease, the fruits are affected. The cause of the fungus is Erysiphales. How does this fungus appear on the tree, scientists still can not give an answer. However, it is precisely known that his spores are capable of hibernating in the bark of the branches and trunk, as well as in the land of the tree trunk. Activation of mushrooms occurs in early spring. This moment coincides with the start of bud break and the formation of the first leaf on the apple tree.

Mealy Dew on Apple Tree

The most favorable conditions for the preservation and primary germination of spores of the fungus is a moist environment. In this case, the speedy development of it occurs in hot weather. Therefore, in areas of agriculture, in which in April - May warm days are replaced by heavy rains, the risk of infection of the tree with powdery mildew is increased.

Important! Mycelium of the fungus in infected kidneys disappears at a temperature of −20 ° C. At the end of severe frosts, signs of a primary disease are reduced. The source of the disease is massively dying.

White bloom on apple leaves and other signs of powdery mildew

So, white bloom on the leaves of an apple tree is nothing else than the mycelium of a marsupial fungus, which is attached directly to the plant's nourishing organs. On such superficial mycelium in the spring and summer period, the abundant appearance of spores begins, after which it begins to grow. During this period, white spots on the leaves of the apple tree are covered with a brown-gray bloom that darkens with time. On the shoots and leaves, black dots begin to appear on the upper side, a gray bloom forms on the lower side, which eventually acquires a brown tint. Affected leaves curl, ceasing to exist.

Note! There is the so-called downy powdery mildew - a disease not only of trees and shrubs, but also of other plants. Its pathogens are parasitic fungi of the phycomycetes class. As a rule, this disease affects the green part of the plant, mainly the leaf. The most susceptible to its attacks are cucumbers, roses, gooseberries, raspberries, peas, strawberries, currants, viola, orchids, hydrangea, violets.

Affected inflorescences lag behind in development, have deformation of stamens and petals on flowers. In appearance, they are distinguished by a yellow-green color. Growing up, the colonies of fungi lead to wilting and fall of the inflorescence without the formation of ovaries.

It happens that the ovary is not immediately exposed to the development of powdery mildew on them. But in the absence of care, the disease can spread to them. An outer mycelium, a marsupial fungus, appears on young ovaries. It disappears with time, but a rusty trace in the form of a netting remains on the peel of the apples.

Young branches, which appeared powdery mildew, weakly go to growth. Usually their top has a brown color. Basically, if they do not fade during the growing season, they freeze through half of the total in winter.

Powdery mildew

Biological agents

  • Phytosporin. Microbiological preparation based on live spores and cells. The period of processing trees 1 time in 2 weeks in any weather.
  • Baikal m. This preparation contains live bacteria that feed on microorganisms, including fungi. Sufficient concentration of the drug is 10 ml per 10 liters of water (1: 1000). Use as phytosporin.

Folk remedies

  • Ash. The most common measure for protecting apple trees from powdery mildew is shedding leaves with ash. It is not a comfortable habitat for mushroom spores. Also, ash helps to protect against insect pests.
  • Another available protection method is serum use. Preparing an aqueous solution in the ratio of 1:10. They are disinfected affected areas. The resulting film blocks the access of oxygen to the spores of fungi, which contributes to their death.
  • Treatment can be carried out with mustard powder. For this 2 tbsp. spoons of powder dissolved in 1 bucket of water. This solution is sprayed.
  • You can also do decoction of horsetaildiluted in water in a ratio of 100 g per liter. Another way is to combine 5 g of copper sulfate, 50 g of liquid soap and dissolve in 5 liters of water.
  • The most common and most affordable tool in the treatment of powdery mildew folk methods is table soda. It is mixed with other ingredients for treatments for diseases.

There is no universal rule for creating a solution based on soda. There are many recipes. Here are two of them:

  • In 10 liters of hot water dissolve 100 g of soap, constantly stirring, add 2 tbsp. spoon of soda. Bring to complete dissolution of the components.
  • 25 g of soda, 5 g of liquid soap are mixed in 5 liters of hot water and brought to complete dissolution.

Note! The resulting solutions are cooled. They are sprayed every 10 days.

Preventive measures

To obtain a good harvest of large ripe apples, it is important not to bring the development of diseases to extremes. Therefore, we must begin to act even before the onset of the first signs of powdery mildew, while conducting preventive measures.

In the summer, you need to carry out preventive pruning of diseased shoots, if any, to collect fallen leaves. Pruning helps to prevent crown thickening.

At the beginning of the ripening period, phosphorus-potassium fertilizers are introduced. This type of fertilizer not only affects the size, taste and color of apples, but also gives additional strength to the tree to fight disease and prepare for wintering. Fertilizers are made not under the root, but in a near-stem circle with a radius of 2 m.

Important! So, one of the most important moments is the correct tab of an apple orchard. For planting choose resistant to powdery mildew varieties. It is important to maintain a sufficient distance between rows and between rows for ease of treating trees with preparations, pruning branches and harvesting. The distance affects the mode of ventilation, does not allow the overmoistening of branches.

In the autumn, digging is carried out to a depth of about 30 cm. This contributes to the death of bacteria that have developed in the upper soil layer and additionally enriches the root system with oxygen. Spraying with chemical and biological preparations can also be carried out in order to prevent. The main spraying is carried out in the following vegetation periods:

  • ripening of the kidneys,
  • the beginning of flowering (when the buds soften),
  • when flowering is over,
  • The following 2 sprays are repeated every 14 days.

In early spring, when the snow had just melted and the wood dried out, and in the fall, when the leaves had fallen off, they carried out preventive spraying with 3% solution of ferrous sulfate to destroy the remaining bacteria and prevent them from hibernating under the bark.

So it is so easy and simple to overcome diseases and pests of apple trees. But this can be avoided if the time to carry out prevention. And then no powdery mildew spoils the harvest!

Powdery mildew causative agent

Like every disease, it has its own reasons for its appearance. Understand what powdery mildew is and how to deal with it by determining the source of infection.

In the nation, the ailment described is called linen or ashen. These names are derived from the characteristic white bloom forming on plants during the infection period. The pathogen, which provokes powdery mildew, is formed by the pathogenic ectoparasitic mycelium of the erisyphus class. It looks like flour dust settling not only on fruit trees, but also tops of salads, tomatoes, cabbage, and other “inhabitants” of the garden space.

Microscopic fungus has a specific habitat - this is the upper layers of the soil. There is no such soil where the mealy mycelium does not live. With proper care of the plant, it is in an anaerobic state. An active life cycle takes a start under certain conditions. About this further.

Causes of the disease

Powdery mildew often infects young apple trees, smoothly moving to more established trees. Mycelium envelops foliage, inflorescences, ovaries in early summer and late fruits already formed. All this contributes to improper care, lack of irrigation, weakness of planting. This, perhaps, is the basic reason for the onset of the acute infection stage. Among the attendant grounds of harm are:

  1. Illiterate choice of fertilizers.
  2. Cultivation of soil for introduced varieties vulnerable to many pests.
  3. Increased landings.
  4. High nitrogen concentration in soil.
  5. A sharp drop in temperature.
  6. A relatively long period of cooling (7-10 days).

Eliminating the above-described reasons for the appearance of a pathogen, unpleasant consequences can be avoided, such as damage to plantings, and a decrease in crop yields in the autumn.

Attention! Mycelium is able to circulate through the air, water, smoothly settling on plants. Even infected human hands, garden tools can become carriers of microorganisms.

Signs of Powdery Mildew

The main symptom in the form of white bloom on the green parts of the apple tree is indicated. You can understand that a tree is infected by other identifying "marks" dispute:

  • lancet deformity of foliage (curling, coarsening of the structure, thickening, loss of turgor, redness, drying, falling off),
  • dying off the tips of the cuttings,
  • intensive growth of lateral buds of the lower tiers of the tree,
  • crown thickening.

Folk methods of treating apple tree

Traditional methods of struggle applied to any disease-causing organism have always been effective: they are time-tested, reliable and accessible.

For processing the garden, you can use soda and soap. To prepare the composition, the last ingredient is rubbed on a grate, dissolved in water with soda. The proportions are taken arbitrarily, a small amount. The resulting liquid should be irrigated not only infected areas, but the entire surface of the tree.

Attention! In the recipe, you can skip soap, since soda, being a natural antiseptic, can effectively master the task on its own.

Treatment of plants with copper chlorine oxide is no less applicable method of dealing with powdery mildew in horticulture.

The stores sell already prepared dry formulations. There are a large number of them. Act differently, depending on the volume of localization of spores. Assessing consumer demand, marketers identified a few favorites in the fight against powdery mildew. These are: “Tebuconazole”, “Fitosporin”, “Cumulus”, granulated urea, “Impact”, “Topaz”, “Topsin”.

Almost all products are diluted with water before use. To prepare the composition, it is important to follow the recommendations on the package.

Caring for the garden always gives its fruits in the form of a good harvest, so it is important to detect and prevent illness in time.

Mealy dew on apple trees. How to fight?

How to recognize the disease?

Mealy dew is common pest of garden trees. It appears in early spring on shoots and full buds. Visually similar to a powdery white bloom, which is easily erased, but then it appears again, turning into a thin, tough brown crust. Slow down, if not stop the growth of the plant. Leaves wither, shrivel and fall, flowers and buds fall off. The cause of the disease is a fungus of the Erysiphales group. Infected leaves grow coarse, shrivel and soon before time fall. Over time, this disease destroys all the organs of the plant: leaves, bark, young buds.

The circumstances leading to the appearance of the pest

  1. Condensed landing.
  2. Lack of watering.
  3. Lack of nutrients.
  4. Severe temperature drops.
  5. Abundance of nitrogen fertilizers.

Among trees, apple trees, maples, elms, some species of oaks, and acacia are most often affected. Of the flowers at risk: rose, phlox, tuberous begonia, zinnia. From berry bushes currants, gooseberries.

Threat of disease

It is dangerous primarily for the apple, because the disease reduces yield by 40–60%. This disease is especially scary in nurseries, as a fungal disease affects a fairly large number of trees.

Great damage is caused to trees due to the fact that the disease significantly reduces the resistance of apple trees to low temperatures.

This disease is not transmitted to man, as well as other vegetable fungal diseases.

Even weakly infected with fungus apples become tasteless, and then, provided that there remained edible pulp. Such fruits are not subject to storage. Fungal pathogen is dangerous in the garden only for other apple and pear trees. Mealy dew is a serious disease, and like any disease, it must be treated and not to forget about preventive measures.

Methods of prevention and control

The sooner you start treatment, the higher the chances for a favorable outcome of the case. Treatment at the initial stage will relieve the apple tree of powdery mildew for a year, and if the disease is neglected, it will take years to fight this disease.

List of ways to combat the disease:

  • Sulfur Group Preparations.

Colloidal sulfur is an excellent tool in the fight against ailment and not only that. Make the processing of apple trees better as soon as the first buds appear. In total, there are three treatments, but if the tree is heavily infected, then it is possible four or six times. For the first time, a two percent solution of colloidal sulfur is prepared at the rate of 20 grams per 10 liters of water. The second time it is already possible to process the one-percent solution as soon as the flowering is over. It is necessary to process the third time 15-20 days after the second time. But in no case no later than 20 days before the harvest.

  • Bordeaux mixture.

It is a broad-spectrum fungicide that perfectly treats and provides prevention.

Professionals advise you to spray apples with a 3% solution of liquid in early spring and 1% during the growing season. It will take 10 liters of the finished solution for one adult tree and 2 liters for a young plant. Processing Bordeaux liquid should be done every 3 years.

  • Treatment with Topaz.

This drug has proven to be a reliable ally of both professional and amateur gardener. It is a fungicide used for the treatment and prevention of fungal diseases. The main active ingredient of this drug - penconazole penetrates deep inside and prevents the sporulation of the disease.

The solution is prepared 10-15 ml per 10 liters of water. It is necessary to process trees two - three times. Spray the trees with a warm solution.

  • Soda Ash.

Gardeners recommend one very good recipe. Trees are treated with a mixture consisting of 50 grams of soda ash and 40 grams of ground laundry soap per 10 liters of water. Treated with this solution trees 3 times every 7 days.

  • Manganese solution.

For 10 liters of water, 3 grams of potassium permanganate is required - a weak pink solution is obtained. Trees are processed with this solution. Especially good for prevention.

  • Pruning infected branches.

Pruning is done not only in winter, but in the spring, after the shoots blossom, and at the end of flowering. Cut branches are necessarily destroyed, because the fungus is very tenacious. It can spread by wind, birds and insects up to one kilometer without losing its functions.

  1. Ordinary ash, infused for 24 hours in water, and diluted in a ratio of half a bucket of ash per 10 liters of water, helps in combating this disease.
  2. It is plentiful enough to water the trees: supporting the soil in a wet state makes trees stronger and healthier.

Mistakes that gardeners make when treating powdery mildew

  1. It is very important to avoid a fairly common mistake that many novice gardeners make when they first encounter this problem! Namely: spraying only infected trees. Properly process all apples and pears, because the causative agent of the disease is the same.
  2. Try to properly feed the trees and do not abuse nitrogen fertilizers. Since nitrogen fertilizers not only stimulate growth, but because of excess feeding, they increase the growth of fungal organisms.
  3. Be careful when choosing seedlings. It often happens that the gardener is already acquiring infected planting material.

Apple varieties that are resistant to powdery mildew

Try to pick varieties resistant to the disease. Experienced growers recommend proven zoned apple trees.

Regions where this disease is most common.

Mealy dew is mainly found in the countries of the former USSR. Gardeners in Russia, Ukraine, Belarus, Kazakhstan, and Moldova face it. Armenia

This disease "likes" abundant dew, frequent fogs, dry weather, so it is characteristic of more southern regions.

What is this disease

Грибковое заболевание садовых плодовых деревьев, кустарников, корнеплодов имеет несколько названий, самые распространенные — это:

What looks like a white bloom on leaves, flowers, fruits, is the mycelium of microscopic fungi multiplying exponentially, with every day a colony of pathogenic fungi captures all large surface areas of the leaves, bark and other external parts of the plant.

Spores are easily transferred by wind and insects, which, if one tree is sick, a plot threatens to develop into a real epidemic of the entire garden.

A fungal disease develops on the bark, leaves and fruits. If at the early stage of a lesion in the fight against this scourge, most of the crop can be saved, then with apple disease at the fruit ripening stage, losses can be up to 80% of the crop.

Who is the causative agent

Powdery mildew is caused by the marsupial fungi of the order Erysiphaceae (Erysifidae), there are more than 700 species that cause a mealy plaque - 100. Erysiphe, which causes Oidium, belongs to this class.

Powdered mildew mushrooms are pyrenomycetes, each of the agricultural plants is affected by representatives of a certain species:

  • Blumeria graminis parasitizes on cereals.
  • Trifolia precipitates legumes.
  • Sphaerotheca mors-uvaevneet gooseberry and black currant.
  • Betae threatens sugar beet yields.
  • Cichoracearum spoils potatoes, tobacco, pumpkins.
  • Sphaerotheca settles on roses and other ornamental shrubs.
  • Uncinula necator prefers grapes.
  • Podosphaera is a common threat to fruit trees, including apple trees.

The peculiarity of parasitic mealy fungi is that their colony lives only up to the time when the plant is alive. Attached to the surface of the leaf or stem in early summer, the mushrooms will die with it.

Parasitic activity of fungi

Mycelium of fungi causing the disease, superficial with appressoria (suckers). For fixing on the leaves, the fungi germinate into the plant cells with short hyphae with haustoria. During the growing season, fungi reproduce plants conidia (asexual stage), in tropical conditions, it may be the only one. Conidia are islands or chains.

In the temperate continental climate, fungi have 2 stages of development - asexual and sexual (marsupial).

Like all mushrooms, erysiphatic have fruit bodies - cleistothecia. On a globular mushroom with a concave tip, there are appendages in the form of simple or branched outgrowths. Each of them contains from 1 to 22 asks, they in turn are a container for 2-8 ascospores. With such fertility, the mycelium will conquer the entire fruit tree in a matter of days, unless preventive and curative measures are taken in time.

Distribution area

Mycelium of marsupial fungi, causing belle, does not tolerate severe frosts, it can overwinter the mycelium, provided that it is located deep in the bark of the tree affected in the previous season. Based on the harsh climatic conditions - severe frosts, a short, dry, hot summer, fruit trees are most rarely affected with powdery mildew grown in Siberia and other northern areas.

Almost powdery mildew on fruit trees can be found anywhere in the world, the largest areas of destruction are found in countries with a temperate continental climate.

The higher the humidity of the air and the soil, the less sunny days in the summer, the higher the risk. The most favorable conditions for the spread of pathogenic fungi are the Baltic States, the north-western regions of the Leningrad Region and the Moscow Region. Slightly lower, powdery mildew causes damage to the crops of the Krasnodar Territory, Kazakhstan, Uzbekistan, Ukraine, Belarus, Moldova.

The main causes and factors of the disease

Between the plants, the disease spreads conidially, methodically capturing all new patches on the leaves and bark of the infected tree and its neighboring drupes, berry, fruit trees and shrubs.

Favorable environment for the mycelium create:

  • soils with poor water conductivity
  • lack of sunlight at high air temperatures
  • mild winters with thaws,
  • warm, rapid spring after a snowy winter.

Under such natural conditions, the mycelium will develop rapidly. At the maturation stage, spores and the heavy rains will contribute to the multiplication and transmission of the disease.

Signs of tree infection

The white translucent bloom formed on the shoots and leaves at the stage of the appearance of the first leaves is a sign of the manifestation of the disease. At the same time, buds that have not yet blossomed begin to wither, deform, turn brown, fade and fall.

The sites of the lesion only initially look white, the development of the disease is indicated by a denser silvery plaque, as such, it seems due to the formation of cleistothecia.

At first, these are rare black dots; at a later stage, the fungal coating becomes brown. On the fruits white bloom - a short-lived phenomenon. Fungus infected apples acquire brown lignified spots and streaks on the skin.

What is dangerous for a tree

Despite the fact that the plaque can easily be wiped from the leaves, shoots and even bark, the disease has already affected the epidermal cells of the plant - has sprouted in them. The remaining inside the hyphae and haustoria continue to parasitize, due to this, after a while the spot becomes gray, brown or purple. The mycelium takes away all the vital juices from its donor - the leaves dry out, the ovaries do not have time to form, and the available fruits fall prematurely or lose their presentation, do not gain the standard weight for a variety.

Mycelium of fungi causing powdery mildew on apples most often does not survive wintering, but under favorable breeding conditions it can ruin a young seedling that has not become stronger by compacting the mycelium. Adult apple trees with chronic dew cease to bear fruit long before the end of the characteristic period for the variety.

For your information: the incubation period is 4-9 days.

Powdery Mildew Drugs on Apple Tree

A universal remedy for fungal infections and insect pests of fruit trees is colloidal sulfur. A two percent solution is sprayed on the trees during the budding period, until the flower bowl opens. At the end of flowering in the prophylactic purposes is processing one-percent composition.

When processing a universal fungicide - Bordeaux mixture, a 3% solution is taken for the first spraying, and a second solution is required for the second. In order to effectively protect apple trees from re-infection, it is recommended to use the pentapase preparation “Topaz”, it penetrates deep into the tissues of the tree and fights the pathogen from the inside, and not only the superficial manifestations of the disease.

Just like Topaz, gardeners are in demand:

In the absence of specialized chemicals on hand, there are several options than to treat an apple tree when it detects the first signs of ash.

The causes of the emergence and spread of the disease

The causative agent of the disease is a fungus of the group Erysiphales spread by wind, insects and birds, penetrates into the buds of the apple tree, and further affects all the ground parts of the plant - shoots, flowers, leaves. Fungal spores grow deep into young tissues, using the sap of plants for their nutrition. At the same time it spreads intensively throughout the apple tree. Mature spores of the fungus are well preserved and overwinter on infected leaves. The destructive temperature for them is minus 27 0 and more.

Popular remedies for powdery mildew prevention

Copper-containing preparations help well from many fungal diseases:

  • Copper sulfate is used for prophylaxis twice a year, in early spring before bud break and in autumn after collecting fallen leaves. They process not only the crown of apple trees, but also the entire area of ​​the circle of the stem.
  • Bordeaux mixture is used like copper sulphate.
  • Lime and copper sulphate are first dissolved in different containers, and then combined.

Note! In the preparation of Bordeaux mixture is important sequence:

  1. In 5 (five) liters of water dissolve 100 g of copper sulfate.
  2. Separately, dilute 100 g of lime to 5 liters of water.
  3. Lime milk filter. Slaked lime is poured into a solution of copper sulfate.

Tip # 2. Do not violate the sequence of actions. For Bordeaux mixture is not suitable plastic, aluminum utensils.

Comparative analysis of the effectiveness of sprayers for the treatment of apple:

Spraying range up to 10 m.

Convenient for spraying tall apple trees.

The engine adjustment system is located in the spray handle.

Analysis of 5 brands of drugs for apple powdery mildew

When the agronomical methods did not bring the desired results, and the apple tree fell ill with powdery mildew, it is necessary to resort to chemical protection. Modern fungicides come to the rescue. Every year the range is replenished with new developments, but still well-known drugs are well-known in the market of protective equipment.

1 hour. The number of treatments - no more than two. Waiting period 30 - 40 days.

Folk methods for the prevention and treatment of powdery mildew on apple

Chemical use is undesirable during fruit ripening. During this period, as well as for the purpose of prophylaxis, safe methods are used, tested by experienced gardeners.

  1. Extract 4 (four) heads of chopped garlic in 10 liters of water.
  2. Infusion of marigolds, calendula, wormwood, pyrethrum, celandine, at the rate of 3 kg of finely chopped plants per 10 liters of water. Apply both one type of plants, and mixes.
  3. Pyrethrum and other useful plants can not only be used for infusions, but planted in the orchard to protect against powdery mildew.
  4. A weakly pink manganese solution is used to prevent powdery mildew.
  5. Milk (or serum) diluted 1:10 acts on the pathogens as an active competitor. Lactic acid bacteria displace fungal pathogen.
  6. Ash infused in water for 1 day at a ratio of 0.5 buckets of ash per 8 - 10 liters of water.

Powdery mildew treatment plan by day:

(or blue vitriol)

1 month for winter varieties

In which regions apple powdery mildew is more common

Favorable conditions for the spread of fungal mildew pathogen are dry weather, frequent fogs, and abundant dew. Such climatic features are typical for the southern regions. Especially intensively the disease develops in the Krasnodar region, in the Kuban, in the warm part of the Volga region.

Rubric: Questions and Answers

Question number 1. Can neighboring apples and other cultures become infected?

The fungal pathogen of powdery mildew is dangerous only for other apples and pears. On other fruit and berry crops and garden plants does not apply.

Question number 2. Is apple powdery mildew dangerous for humans?

Apple powdery mildew, like other vegetable fungal diseases, is not transmitted to humans.

Question number 3. How long can you get rid of powdery mildew?

It is impossible to completely eliminate the possibility of infection, since the source of the disease is carried by wind, birds and insects. But it is quite possible to carry out agronomic, preventive and curative measures, thanks to which the apple trees will not fall ill with powdery mildew. If, nevertheless, the infection has occurred, the time during which it can be overcome depends on the degree of the disease. The treatment, started in the mild stage, will relieve the apple tree of symptoms in one year, and it takes years to overcome the advanced cases.

Question number 4. Is it possible to collect fruits from a diseased tree?

Infected apples lose taste. Even if the edible flesh remains on the slightly affected fruits, it is significantly inferior to healthy ones. In extreme cases, they can be cut and immediately eaten. These apples are not stored.

Question number 5. What apple varieties are powdery mildew resistant?

There are no varieties that are resistant only to powdery mildew. Working on the creation of new hybrids, breeders are trying to strengthen the immunity of the apple from many adverse factors. Experienced gardeners try to acquire proven zoned apple trees.

  • Eder,
  • Mavka,
  • Amulet,
  • Red amber,
  • Dawn,
  • Refree
  • Union,
  • Fairy,
  • Fortune,
  • Mascot,
  • Carmen,
  • Talida
  • Marshmallow
  • Kupava,
  • Prima
  • Jonagold
  • Golden summer
  • Mutsu,
  • Linda,
  • Orion,
  • Prestige,
  • Palette,
  • Springwell,
  • Argo,
  • Red poppy.

Serious gardener's mistakes in powdery mildew treatment

Error number 1. Purchase of infected seedlings.

Often, the question, “Where did powdery mildew come from, if it was not there before?”, You can safely answer: “You bought it!”. This situation happens if in nurseries where planting material is grown, plant protection measures are not observed.

Error number 2. Improper feeding of apple trees.

Novice gardeners like to repeat that nitrogen is a growth stimulator, forgetting to add that it is a green mass. But not only plants need nitrogen fertilizers, they also stimulate the growth of fungal organisms, therefore, contribute to infection of the apple. This happens when excessive fertilizing is done.

Error number 3. When signs of disease appear, only the tree on which symptoms are found is treated.

Spray need all apples and pears, they have a common pathogen.

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How is she dangerous

White bloom on the leaves of apple trees is not just an unpleasant thing. First, the parasite's mycelium attaches to the feeding organs of the apple tree. It interferes with its growth and fruiting.

If the disease is highly developed, the affected leaves and fruits do not have time to develop and quickly fall off. The fungus destroys both the shoots of the apple tree and the ovaries that have already been formed (they shrink and fall off as well as the fruits). Powdery mildew also affects the trees' hardiness: during the winter, infected pastures and buds have time to die.

The powdery mildew is most dangerous in nurseries, because here it can hit many trees at once. Here it develops very quickly. Yield losses when running mycosis can range from 40% to 60%. Sometimes, however, the fungus dies in the winter. But usually the spores of the parasite live in the bark of the apple tree in winter.

Mycosis affects all organs of the apple tree. This also applies to other fruit trees. Symptoms become noticeable in April, and sometimes in March. First, the plaque on the shoots whitish or with a silvery shade. Later it becomes gray-brown and further darkens. You can find dark dots on it - these are spores of the fungus and its fruiting bodies, they are cleistothecia.

Petioles and leaves bloom from the underside. Further, it becomes rusty-brown color. The leaves stop their development, curling up into a tube along the central veins. Similarly, the buds of the apple tree and its flowers crumble and wilt. Fungus sporonosit about three months and this is enough to destroy the harvest.

On the apples themselves plaque appears when they are just beginning to form. After it disappears, leaving only a brown mesh, similar to the cork fabric that appears on the fruit after any mechanical damage. By the way, in the early stages, the bloom from the fruits and leaves is easily removed, but it appears with a vengeance after it has been removed, acquiring a purple hue.

Inflorescences acquire a green-yellow color. They are lagging behind in development. Flowers do not appear at the same time, but at different times, they can be deformed and stamens, and pistils.

Powdery mildew is spread mostly in Kazakhstan, in the North Caucasus, in Central Asia, as well as in southern Russia, in Moldova and in Ukraine. In Georgia and the Krasnodar Territory, as well as in Kyrgyzstan, the infection of apple trees is slightly lower. Much less common in the Volga region and in the Baltic States.

How to deal with it

The disease is dangerous and devastating, so you have to fight him seriously. First of all, watering should be moderate, and the humidity of the earth should be monitored constantly. This will increase the endurance of apple trees. But among the most effective chemicals are the following:

  • Colloidal sulfur. This is the leader among the fighters with powdery mildew. It also copes with plant mites, scab, ascochito and anthracnose. Processing it should begin even when the trees just appear buds. For a start, a two percent solution will suffice (we take 20 g of colloidal sulfur per 10 liters of water). Next, spray the solution with one percent. The third time - after two or three weeks and no later than three weeks before picking apples. If the apple tree is severely affected, you can spray up to 6 times. It is important to wet all the organs of the apple: the solution must drain them.
  • Bordeaux liquid. Also has a wide spectrum of action. Copes with downy mildew, and with scab, and spotting, and sulfur rot. In March-April, we spray the apple with a solution of three percent, during the growing season with a one-percent solution.

Up to 10 liters of mortar goes to an adult tree, about two liters to a young tree. Do not forget to handle the barrel. A healthy apple must be treated with such liquid once every three years.

  • Topaz. The active ingredient is penconazole. Means does not allow the fungus to spore. It is rather economical, for a plant it is not toxic at all. For 10 liters of water you need about 15 ml of funds. We process from two to three times.
  • Soda Ash We need it for 10 liters of water of about 50 g. We also add laundry soap (40g).
  • Potassium permanganate take 10 liters of water about 3 g, We process three or four times in a row.
  • Copper oxychloride may also be effective. We take it on 10 liters of water 40 grams.

Mealy dew is a very dangerous and destructive disease. The main thing in dealing with it is not to overlook the very first symptoms of mycosis. Prevention and control should be regular. One time processing will not be enough.

Control measures

Кроме трехразовых опрыскиваний фунгицидами за сезон, необходимо строго дозировать подкормки. Nitrogenous fertilizers increase the ability to develop not only crops, but also fungi parasitic on them - if the recommended levels of nitrogen fertilizers are exceeded, the mycelium will spread particularly rapidly. Potassium and phosphate fertilizers reduce its vital activity.

Prevention at the initial vegetation cycle stage is important, but how to deal with powdery mildew during fruit ripening? Folk remedies do not affect the quality of the fruit, with an increased risk of infection of the plant with powdery mildew, it is recommended to spray apples with potassium permanganate or a solution of soda with soap once every 10-14 days.

If the tree is infected, the manifestations of the disease not only on the leaves, but also on the branches, trunk, then without the means "Topaz" or similar with it in the action of the fungicide can not do. The first 2 sprays are carried out at intervals of 3-4 days. Further, before the ripening of the fruit, it is necessary to carry out prevention.

Treatment of an adult tree

Processing high apple with a dense crown is difficult, spraying is not only on the surface of the leaves, it is necessary to process, branches, stem, lower part of the leaves. This will require an assistant, pumping the solution, and personal protective equipment - glasses, a suit, as much as possible protecting areas of the body.

What to do with an apple tree when an entire branch of an adult plant is struck? It is easier to remove and burn, in such a case, stepladder, shears, handsaw, garden var should always be at hand. To prevent the development of powdery mildew after the winter from the mycelium overwintered in the soil:

  • Mulch is removed from under the tree.
  • Spring and autumn whitewashing the trunk.
  • No last year's leaves and fruits should not be on the site.

Manifestations of the disease on apples do not affect the taste, but the apples will be less juicy. If it is possible to overcome pathogens with the help of folk remedies or gentle dosages of chemicals, then the crop can be used as food.

Attention! To find out after which treatments apples are suitable for food, you can on the packaging of professional tools. The manufacturer’s instructions will be relevant if the recommended proportions are strictly followed during use.

How to save young seedlings

To save apple seedlings in the planting season, they are soaked for a day in a weak solution of potassium permanganate (potassium permanganate). Water should get a light pinkish hue, a strong solution can cause burns, the plant will hurt. To improve the survival rate of the seedling, it is better to use growth stimulants, and it is better to give up the nitrogenous top dressing, because in the first season the apple tree (on any rootstock) is not expected to harvest.

Prevention

When sampling a plot for planting, avoid proximity to the plants affected by the fungus, protect it on the leeward side, but do not plant in the shade of a house or a monolithic fence. Be sure to follow the specific height of the intervals recommended for fruit trees.

Be sure to thinning the crown, remove the affected and old (not fruit-bearing) branches, harvesting fallen leaves and fruits, carrying out mulching and whitewashing, applying potash and phosphate fertilizers.

Seasonal processing

Phosphate spraying of apple and other fruit trees after harvest is carried out, but until the leaves have fallen off and turned yellow. The solution is absorbed through the leaf plates, thereby protecting the plant from powdery mildew and other fungal infections after the winter.

On varieties of apple trees of late ripening leaves fall off before the crop is harvested from the tree, in this case it is necessary to add phosphate through the soil with the last watering of the season. Thinning the thickening crown of the tree prevents the rapid spread of the disease, whitewashing the trunk makes it difficult for the hyphae and haustories to penetrate the plant bark.

Powdery mildew resistant varieties

For the resistance of apple trees to certain strains of diseases in plants, as in all living organisms, the gene is the strongest in apple tree breeding varieties:

  • Amulet,
  • Argo,
  • Gloucester
  • Duet,
  • Marshmallow
  • Golden summer
  • Carmen,
  • Red poppy,
  • Red amber,
  • Kupava,
  • Linda,
  • Mutsu,
  • Orion,
  • Palette,
  • Prestige,
  • Dawn,
  • Redfrey
  • Springwell,
  • Union,
  • Talida
  • Mascot,
  • Fortune,
  • Fairy.

This is not a complete list of powdery mildew resistant apple trees. For each of the regions in the local nurseries you can find other varieties with high levels of sustainability. When choosing a variety of apple trees, it must be remembered that immunity to a single disease in an apple tree can be compensated for by its low resistance to other types of pathogens.

Symptoms and signs

Mealy dew infects young shoots, leaves, flowers and fruits. The symptoms are most noticeable on the leaves and fruits.

Overwintering in dormant flower and sprouting buds, infection infects the tree for the next year. In the spring, when the first leaves open, the fungus invades the young green tissue of the plant. Infected kidneys have a silvery gray appearance. Often, during the spring development of an apple tree, the first leaves are falling, and their growth is slow.

Subsequently, as the plant forms color and fruits, the infection begins to penetrate deeper into the leaves, flowers and apples. Strongly affected trees weaken by the middle of summer, the powdery mildew mycelium darkens and is covered with numerous processes.

In contrast to the primary infection with an infection, in which the leaf is affected even before it leaves the kidney, a secondary one occurs when powdery mildew spores land on the already opened foliage. Fungal colonies consisting of mycelium and spores appear as a white patina. Secondary infection appears first on the lower surface of the leaf, less often on the upper in the form of chlorotic spots. Leaves infected along the edge may curl or fold longitudinally. As the disease progresses, the affected tissues begin to acquire a silvery gray tint.

Infection on the flower or young fruit leads to discoloration and shape distortion. The yield and quality of apples decreases. Infected buds have a silver-gray appearance and open 5-8 days later healthy, if they bloom at all. The petals are modified and have a pale yellow or light green tint.

Inflorescences can become shriveled, they rarely bear fruit. Secondary infection occurs on the newly formed flower buds. This is one of the main reasons why there is no harvest the next year after the defeat of powdery mildew.

Appearance and distribution

Trees affect the fungus, which is found in every region where apple orchards grow. During the growing season, the colony constantly breeds spores of asexual reproduction on short petioles. Spores do not need moisture to germinate and they spread very quickly to the wind. If they land on susceptible tissues, new mycelium colonies are produced.

Apple buds serve as wintering grounds and are the earliest source of infection next spring. However, extremely low winter temperatures adversely affect the survival of the powdery mildew.

The fungus also produces genital spores in fruit bodies. They are tightly grouped and have apical and basal appendages. They are formed at the end of the growing season and serve as wintering structures, but do not play any role in the creation of a new epidemic, since they do not germinate well. Fungus winters in:

In the spring, when the plant begins to wake up, the fungus resumes growth, striking new shoots and young leaves. This primary infection is the main cause of the epidemic, since disputes are spread in large numbers after a short period of time. They will germinate at high relative humidity (more than 70%, which is usually present in the microclimate of the lower surface of the sheet) and at a temperature of from 10 to 25 ° C. Unlike most of these fungal pathogens, leaf wetting is a deterrent to infection. The youngest leaves are most susceptible, but become more resilient as they grow.

Mold colonies usually appear first on the bottom surface of the sheet in the form of white felt spots. Spores germinate, forming growths that swell and then flatten out. These structures release specific enzymes that allow the fungal infection to invade the epidermal cells.

The fungus lives and eats due to haustoria. These are organs that form inside the living cell and absorb nutrients from the plant. As the mold colony expands and secondary infection leads to the formation of a new colony, the process does not stop until the tissue suitable for feeding the fungus disappears.

Methods of struggle

It is possible and necessary to fight the disease, for this you need to spend some of your own time, but thanks to the work you can get a high-quality and rich harvest. Experienced gardeners offer several ways to fight infection:

  • sluggish and lifeless shoots and leaves must be removed,
  • all residues after cardinal pruning, including old leaves, must be burned,
  • on the ground around the tree it is necessary to pour ash layer not less than a centimeter thick,
  • it is necessary to make regular dressings using potassium and phosphorus,
  • In the fall and spring, trees are necessarily treated with fungicides.

When spraying the plants, they must “bathe in the solution”, that is, it is necessary to apply it so that each bud and shoot are covered with the preparation. Moreover, the ground around the tree is also cultivated.

Chemicals

Secondary infections and infections of the fruit can be controlled by the use of fungicides. These drugs are almost always used to combat mold and other apple diseases. Fungicides are usually used with an interval of 7 to 10 days from the stage of dense reproduction until the end of the growth of shoots, and this is approximately the middle of summer. Susceptible apple varieties have to be processed up to 18 times per season, if it is necessary to preserve the crop. As far as possible, the use of drugs should be alternated with other actions. Experts advise the use of sulfur in a period of low risk of infection with powdery mildew and plant less susceptible to fungus varieties.

Benzimidazoles have high activity against the fungus, but their use has not been particularly popular lately. Special oils, waxes and biological compounds are also available, but their effectiveness is somewhat controversial. It is difficult to provide the necessary control during the growing season if the problem was ignored at an early stage.

Most effective tools are composed of:

  • copper sulphate,
  • colloidal sulfur
  • copper chloride.

It is necessary to use them strictly in accordance with the instructions. As practice shows, the funds, which are based on sulfur, have a better effect on the fungus. Often you can hear about the fight against powdery mildew with antibiotics, but this makes no sense.

Copper sulfate can be used only once per season, because it has a strong fungicidal effect. It is advisable to use it in the spring, before the first buds bloom. Ten grams of water will need 50 grams of vitriol. There is another recipe: dilute 30 grams of the product in half a liter, dilute the soap in the remaining nine liters of water. When spraying on plants, it is imperative to use personal protective equipment.

A good remedy is colloidal sulfur, which can be used even three days before picking apples. Ten liters of water will require 50 grams of sulfur. Allowed up to six sprays per season. An important condition is that the air temperature should not be below +20 degrees, otherwise the treatment will not bring success.

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