Representatives of the genera are common among lichens Cladonia, Hypogymnia, Parmelia , and among the mosses - Dicranum, Mnium etc. Lichen diseases are found everywhere on all berry bushes and trees.
The description of these diseases of apple trees should begin with the fact that they develop when plantings are dense, poor ventilation, poor lighting of the bushes, and conditions of high humidity are created. Such conditions are very favorable for the development of lichens and mosses, pathogenic microorganisms that cause bark necrosis, stem and root rot. Any plant covered with lichens has a sparse crown and weak growth of shoots; lichens from one tree or shrub quickly spread to neighboring ones.
The thalli of lichens retain moisture on the surface of the bark, which can cause the formation of frost holes in severe winters, and many insect pests constantly overwinter under the thalli. The spread of lichens and mosses indicates, first of all, the weakening of plants.
Seeing a description of the apple tree disease with photographs, you can arm yourself with knowledge about the potential danger and begin to fight it as recommended below.
Control measures. Constant cleaning and removal of thalli from trunks and skeletal branches and spraying plants in the fall with a solution of iron sulfate (300 g/10 l of water).
Look at lichen diseases of apple trees in photographs showing the most typical symptoms:
The main diseases of the bark and trunk of apple trees are caused by fungi and are combined into a group called cancer. Further in the material, these apple tree bark diseases and their treatment are discussed with a description of the characteristic symptoms.
Common or European apple tree cancer.
The causative agent is a fungus Neonectria galligena (Bres.) Rossman & Samuels (syn. Nectria galligena Bres.). Elongated brown spots appear on the bark, which dry out and crack. Beneath them, ulcers with raised edges of callus tissue are exposed. Over the years, the ulcers increase and deepen, and the wood gradually dies. When young plants are damaged, death occurs after 2-3 years.
On the trunks an open form of cancer is detected in the form of deep ulcers, on the branches there is often a closed form, in which the nodules grow together and a gap remains. When the disease manifests itself on a massive scale, deep ulcers also form on the skeletal branches. In the affected wood, sporulation develops along the edges of the canker in the form of whitish-cream pads that dry out and darken over time. The spores recharge neighboring branches and leaves.
Affected leaves become chlorotic, necrotic brown spots without borders appear on them, the leaves gradually dry out and fall off prematurely. Brown spots appear on the fruit on the stem side, which lead to rapid rotting. The infection persists in the affected wood and plant debris.
The disease is widespread on almost all fruit and berry crops, ornamental and deciduous tree species. With dense plantings, constant re-infection of plants is possible. The disease most often manifests itself on weakened planting material and in places of frost damage and mechanical damage to the bark of trunks and branches.
Control measures. Use healthy planting material without any necrosis of the bark and ulcers on the shoots. Compliance with all agrotechnical requirements for growing this crop. Timely pruning of affected branches with cankers and burning them. Individual ulcers in the forks of skeletal branches are disinfected with a 1% solution of copper sulfate and covered with oil paint on natural drying oil. Annual preventive spraying of plant bark before leaves bloom with Bordeaux mixture or its substitutes (HOM, Abiga-Peak).
Black apple tree cancer.
The causative agent is a fungus Sphaeropsis malorum Berck . Black cancer often begins to develop in the forks of skeletal branches of trees. First, reddish-brown depressed spots form, then they darken, and numerous black fruiting bodies - pycnidia - appear on the bark. The affected bark turns black, becomes lumpy and resembles goose skin, over time it cracks, dries out and peels off from the wood in entire layers.
Dark brown spots appear on the leaves and fruits, similar to black rot. When trunks are affected, the disease causes trees to dry out within 1-2 years from the moment the first symptoms appear. When trees are planted in dense areas, the disease quickly spreads from tree to tree, from apple trees to pears.
Only the damage to the bark looks a little different: the cracks along the edge are deeper, the dead bark does not turn black, but is covered with numerous cracks and crumbles easily. When the disease spreads on mature trees, it is necessary to cut out dried skeletal branches every year, which is why the tree crowns take on an ugly appearance. The infection persists in the affected bark and in affected plant debris.
Control measures. Compliance with all requirements of agricultural technology for growing fruit crops, using healthy planting material. Preventive annual spraying of trees, especially trunks and skeletal branches, with 1% Bordeaux mixture or its substitutes (HOM, Abiga-Peak). Timely pruning of dried branches, removal of dried trees, stripping of affected bark, disinfection of wounds, cuts, cuts with 1% copper sulfate and coating with oil paint on natural drying oil.
Cytosporosis, or infectious drying of the apple tree bark.
The causative agents of this apple tree disease are fungi Cytospora schulzeri Sacc. et Syd. (syn. C. capitata Sacc. et Schulz.) and C. carphosperma Fr. - on an apple tree, C. microspora Roberh. - on apple and pear trees. The disease is manifested by browning and death of the bark of branches, skeletal branches and trunks. Numerous convex stromas in the form of gray-brown tubercles are formed on the affected tissue.
At first they are submerged, then erupting, bluntly cone-shaped. The affected bark dries out, acquiring a finely lumpy appearance from the sporulation of the fungus, but does not peel off, but becomes wet. The fungus enters the plant through mechanical damage and spreads from the bark into the cambium and wood, causing premature drying of the branches. Fruit trees in nurseries are severely affected by dense planting and frequent pruning of the crown during the formation process. The spread of infection is facilitated by weakening of plants from exposure to low temperatures, sunburn, and mechanical damage to the bark. The infection persists in the affected branches and trunk bark and spreads when low-quality planting material is used.
Protection measures for apple tree disease are the same as the treatment methods against black cancer.
Look at the manifestations of this apple tree disease in the photo, where all the typical symptoms of bark damage are clearly visible:
Spring diseases of apple trees actually develop during the winter, but their obvious signs begin to appear after the melting of the snow cover and the establishment of above-zero temperatures. The following are diseases of apple tree branches that are more common than others: their symptoms are shown and control measures are described.
Study these apple tree diseases and the fight against them using photos that richly illustrate each type of lesion:
Tubercularosis, or drying out of apple tree branches.
The causative agent is a fungus Tubercularia vulgaris Tode . Conidial stage of the fungus - Nectria cinnabarina (Tode) Fr. The disease occurs on many shrubs and deciduous trees and causes necrosis necrosis (death) of the bark. During the growing season, the leaves and shoots quickly turn brown and dry out. Numerous brick-red sporulation pads with a diameter of up to 2 mm are formed on the surface of the affected bark; over time they darken and dry out. The development of the fungus causes the death of the bark and phloem of individual branches and shoots. Often, infection of plants in gardens begins with red currant bushes, for which tubercular necrosis is the main disease. The infection persists in the bark of the affected shoots.
Control measures the same as against ordinary cancer.
Comber.
The causative agent is a fungus Schyzophyllum commune Fr. The comb plant settles on the branches and trunks of weakened, often frozen trees and causes the development of trunk rot. It affects many fruit trees and shrubs and deciduous trees. On the affected bark, fruiting bodies are formed in the form of leathery thin caps of a grayish-white color with pronounced zonal stripes. The caps are numerous, attached sideways to the trunk or skeletal branches. As a result of the rapid spread of stem rot, the affected trees gradually dry out. The infection persists in the fruiting bodies of the fungus and in the affected wood.
Control measures. Pruning and burning of fruiting bodies, stripping wood, removing dried branches and individual trees. Disinfection of wounds and cuts with 1% copper sulfate and coating with oil paint on drying oil. Annual mandatory preventive spraying of trees before the leaves bloom, so that the drug solution wets the bark with 1% Bordeaux mixture or its substitutes (HOM, Abiga-Peak).
The most common disease of the apple tree trunk is root rot, rivaled in prevalence only by scab. We invite you to find out all the necessary information about diseases of the trunk of apple trees and their treatment so that this defeat does not take you by surprise.
Root rot, or honey fungus, of apple trees.
The causative agent is a fungus Armillaria mellea (Vahl.) P. Kumm. (syn.Armillariella mellea (Vahl.) P. Karst.), causes peripheral wood rot. Honey fungus grows on the roots of living trees and shrubs, as well as on stumps.
Under the affected bark of roots, butts, bases of trunks and shoots, the fungus forms a network of black flat cords - a rhizomorph, with the help of which it actively spreads. Numerous fruiting bodies are formed on the mycelium in the form of yellow-brown caps with a stalk and a membranous ring under the cap. The fungus persists in wood, in the soil in affected plant debris, penetrates the root system of trees and shrubs, causes the death of wood roots and trunks, which is why honey fungus damage is called peripheral rot. The main signs of this disease of apple trees are visible to the naked eye: various annular spots along the entire trunk, covered with a brownish coating.
Control measures. Preventive spraying of trunks and branches with 1% Bordeaux mixture or its substitutes (HOM, Abiga-Peak). Removing and burning affected dead trees along with their roots. At the first signs of infection, the soil under the trees is spilled with a solution of a copper-containing preparation. When industrially grown in a nursery, the roots and butt part of woody plants are treated with a tank mixture: foundationol (0.2%) + HOM (0.4%).
Apple scab.
The causative agent is a fungus Venturia inaegualis Wint . with conidial stage of Fusicladium dendriticura (Wallr.) Fuck. Dark green velvety spots appear on the upper side of the leaves, gradually turning brown, the leaves turn yellow and fall off prematurely. When infected in spring and early summer, the spots are large, later, with repeated re-infections, they are small and hardly noticeable. The spores re-infect the ovaries, less often young shoots, the fruits become stained and become unfit for consumption. With the widespread spread of scab, the marketability of fruits, decorativeness and winter hardiness of trees are reduced. The development of the disease is favored by wet, cold spring and abundant rainfall in summer. The pathogen has a narrow specialization, that is, the fungus affects only the apple tree and does not spread to other trees. The infection persists in the affected plant debris.
Control measures. Collection and removal (possibly composting) of fallen affected leaves. Spraying trees, starting from the green cone phase and, if necessary, in the summer, taking into account the waiting period, with one of the preparations: 1% Bordeaux mixture, HOM, Abiga-Peak, speed, rayok. It’s easier to navigate by the phases: before flowering and immediately after flowering.
Look at these apple tree trunk diseases in the photo, which shows typical symptoms of fungal infection:
Apple tree disease in which leaves curl
Powdery mildew is a disease of the apple tree in which the leaves curl and quickly dry out, and the shoots stop growing.
Look at this apple tree disease with a photo and description, it also talks about possible measures to combat fungal infection in a personal plot:
The causative agent is a fungus Podosphaera leucotricha Salm . As early as May, spots of grayish-white plaque may appear on young inflorescences and leaves, the spores of which re-infect the growing leaves and shoots. Affected leaves curl and dry out, shoots become deformed and stop growing. Affected buds do not produce fruit, and with later infection, a rusty mesh of cork tissue appears on the fruit. Powdery mildew appears more often in dense gardens or due to their low light and ventilation of the plantings. The disease is common on apple trees, but also occurs on pears, only to a mild extent. The infection persists in the fruiting bodies in the affected leaves and bark and the mycelium in the buds of the shoots, from which the primary infection of young leaves begins.
Control measures. Compliance with all requirements of agricultural technology for growing fruit crops, timely removal of heavily affected shoots from young trees, collection of fallen leaves and their composting. Preventive spraying of trees when the first symptoms of powdery mildew appear.
Apple tree rust.
The causative agent is a fungus Gymnosporangium tremelloides Hartig. (syn. G. juniperinum Mart.) , affects mainly leaves, less often shoots and fruits. Orange-red round cushion-shaped spots with small black dots appear on the leaves on the upper side, and orange cone-shaped aecia are formed on the lower side, which turn brown over time. The apple tree is an intermediate host. The fungus overwinters and develops on Cossack juniper. In spring, brown growths with brown mucus appear in cracks in the bark, and the spores re-infect the leaves of the apple tree. When the disease spreads massively, the leaves turn yellow and fall off prematurely. The infection persists in juniper plantings.
Control measures. Spraying trees before flowering or immediately after it with 1% Bordeaux mixture or its substitutes (HOM, Abiga-Peak).
Brown spotting of apple leaves.
Pathogens - fungi Phyllosticta mali Prill, et Del. and Ph. Briardi Sacc . When the first fungus infects the leaves, large angular dark yellow spots with a lighter center and a thin brown rim appear. When infected by the second pathogen, the spots on the leaves are round or angular, light yellow in color, without borders, up to 6 mm in diameter. Over time, small dotted black fruiting bodies of the overwintering stage are formed in the necrotic tissue. The leaves turn yellow and fall off prematurely, which affects the ripening of the wood of the shoots and their frost resistance. The infection persists in the affected fallen leaves.
Control measures. Spraying trees in the spring before flowering and immediately after flowering with 1% Bordeaux mixture or its substitutes (HOM, Abiga-Peak), collecting and removing fallen leaves.
The causative agent is a fungus Ascochyta piricola Sacc ., affects both apple and pear trees. The spots on the leaves are round, grayish, merging with each other, and have no border. Over time, black scattered fruiting bodies of the overwintering stage are formed in the necrotic tissue. Affected leaves turn yellow prematurely and fall off. The infection persists in the affected plant debris.
Control measures the same as against brown leaf spot.
Uniform yellowing of leaves between the veins is associated with a large deficiency in the supply of nutrients to young growing leaves. The reason for this may be frost damage and death of the bark or the spread of root and stem rot, as well as necrosis. With severe manifestation of chlorosis, browning and drying of leaves, dying of branches and trunks are subsequently observed.
Control measures. Timely identification of the causes of chlorosis. Preventive spraying of trees in the spring, before leaves bloom, with 1% Bordeaux mixture or its substitutes (HOM, Abiga-Peak). In case of mechanical damage and frost damage, pruning, removal of fruiting bodies of tinder fungi, all cuts and cracks are disinfected with 1% copper sulfate and covered with oil paint.
Look at these diseases on the leaves of an apple tree in the photo, where all the characteristic signs of damage are visible:
Moniliosis is called a disease of apple tree seedlings, since it mainly affects young trees in the first and second years after planting. On adult plants, fresh branches not protected by bark are affected.
Pathogens - fungi Monilia cinerea Bon. f. mali Worm, and M. fructigena Pers. . The first pathogen causes a burn, in which flowers, ovaries, fruit branches and leaves turn brown and dry out, but do not fall off for a long time. The second pathogen causes fruit rot.
Rot appears in areas damaged by the codling moth. Over time, numerous gray sporulation pads in the form of concentric circles form on rotting tissue. Spores are spread by wind, rain, insects and re-infect neighboring fruits. Infected fruits mummify (dry out) and turn black. Remaining hanging on the branches, they are a source of constant infection.
Look at this apple tree disease in pictures that illustrate its gradual development with symptoms typical for each stage:
Control measures. Collecting carrion, removing mummified fruits, pruning dried branches. Spraying trees in the spring, before flowering and immediately after flowering, with 1% Bordeaux mixture or its substitutes (HOM, Abiga-Peak). In case of severe spread of monilial burn and fruit rot, a third spraying with the same preparations is carried out 10-12 days after the second spraying.
There are diseases of apple trees with curled leaves that need to be recognized as soon as possible, since they pose a danger to other garden crops. Familiarize yourself with such diseases of apple tree leaves in the descriptions further on the page: this will allow you to quickly recognize the signs of their occurrence.
Pestalocia spot of apple tree.
The causative agent is a fungus Pestalotia malorum Elenk. et OM . The spots on the leaves are grayish-brown, round, merging. Over time, numerous black sporulation pads form on the necrotic tissue. Affected leaves turn brown and dry out prematurely. The infection persists in the affected fallen leaves.
Control measures. Spraying trees in the spring, before flowering and immediately after it, with 1% Bordeaux mixture or its substitutes (HOM, Abiga Peak), collecting and burning fallen leaves.
Tobacco necrosis virus on apple trees.
Tobacco necrosis virus Tobacco necrosis virus (TNV) manifests itself as a systemic necrotic reaction. Necrotic spots of irregular shape appear on the leaves, which become concentrated, necrotic, the veins darken, and the leaves die prematurely. Leaf deformation, plant dwarfism, and lack of flowering may occur. The virus affects vegetable, industrial, fruit and berry, flower and ornamental crops. The range of host plants includes representatives of more than 40 families. Transmitted by plant sap and zoospores of Olphidium brassicae.
Control measures. Use of healthy planting material, compliance with all requirements of agricultural technology for growing crops. Timely pruning of leaves and branches with symptoms of viral infection, removal and burning of heavily affected young trees. Disinfection of garden tools (knives, secateurs) in alcohol, cologne, 1% solution of potassium permanganate after working with affected plants.
Look at these diseases of apple tree leaves in the photo, which shows all the signs at different stages of damage:
Diseases of young apple trees most often have a mixed nature. They are caused by several pathogens at once. The most dangerous diseases are the bark of young apple trees, which can develop after an unsuccessful wintering. If apple tree bark disease in adulthood usually progresses slowly and the gardener has time to effectively treat it. But for young seedlings everything is different. Trees can die in a matter of days.
Bacterial cancer, or bacterial necrosis, of apple bark.
The causative agent is a bacterium Pseudomonas syringae van Hall. (syn. Ps. cerasi Griffin) . Causes bacterial necrosis in both stone and pome crops. The disease resembles a burn. Since spring, browning of the buds and bark of branches, blackening and drying of young shoots and leaves have been observed. Black spots appear on the leaves, cracking along the edges of the leaf blades. The affected bark swells, swellings appear in the form of soft blisters, and depressed spots with a violet-cherry border often form.
The wood of the branches and trunks rots, a sharp sour smell of fermented sap appears, and the trees die. Bacteriosis usually begins with linear necrosis of the cortex and progresses into wide stripes. In the chronic form of cancer, ulcers form on the branches and trunks, which gradually increase in size. Gum is released abundantly from the ulcers. The affected wood turns brown and dies, and the cankers dry out. When cut, cavities filled with mucus and gum formations are visible in the wood. The infection persists in the affected branches, and the bacteria are spread by the wind, insects, pruning tools and mainly with infected planting material.
Look at the manifestations of this apple tree bark disease in the photo showing the characteristic signs of the lesion:
Control measures. Use of healthy planting material, compliance with all agrotechnical requirements for growing crops, timely removal and burning of affected branches and dried trees.
Disinfection of saw cuts, small ulcers and necrosis of bark on trunks with a solution of 1% copper sulfate and coating with oil paint. Preventive annual spraying of trees in the spring, before leaves bloom, with Bordeaux mixture or its substitutes (HOM, Abiga-Peak).
Witches' brooms, or proliferation
These are diseases of apple fruits that damage the ovaries at the budding stage.
Pathogen - phytoplasma Apple proliferation, Apple witch's broom . Symptoms of the disease appear in July-August. On the affected shoots of the apple tree, dormant buds wake up en masse and thin, erect side shoots with short internodes grow. The leaves are small, with short petioles and large stipules, the edges of which have sharp, atypically large teeth.
The fruits on infected branches develop small, on long stalks, flattened and tasteless. Sick trees bloom later than others, their flowers turn green and deformed, leaf buds open at a later date, and leaves turn yellow and fall off prematurely. Often, abundant root shoots develop around the trunk. Affected seedlings have a compact appearance due to reduced growth and bushiness of the tree. The disease is spread by grafting, budding, planting material and possibly seeds. In addition to the apple tree, quince is also affected. The infection persists in the affected shoots.
Recommended control measures will tell you how to treat this disease in apple trees., among which the most important thing is the use of healthy planting material and compliance with all requirements of agricultural technology for growing crops. Timely pruning of branches with witches' brooms, removal and burning of heavily affected young trees. Disinfection of garden tools - knives, secateurs in alcohol, cologne, 1% solution of potassium permanganate after working with affected plants.
Corerification of apple fruit skins is a non-infectious disease of fruits. Slightly depressed brownish spots of suberized tissue appear on the fruits, and they are often slightly deformed. Late spring frosts during the flowering of gardens have a negative impact on the development of flowers, ovaries and young leaves. Frozen flowers and ovaries turn brown and crumble, leaves become deformed and dry out, and partially damaged fruits grow, but their skin becomes corky.
How this apple tree disease manifests itself is shown in the video, which demonstrates the most striking signs:
Control measures. If the temperature is expected to drop during the flowering of gardens, it is recommended to light fires and create a smoke screen. Young trees and shrubs can be covered with spandbond or lutrasil.
Damage to apple trees by low temperatures.
In winters with low temperatures, frequent thaws and insufficient snow, the bark, cambium, and trunk wood of fruit trees are damaged, and frost cracks appear on the trunk and skeletal branches. Solar-frost burns are observed during sharp daily temperature fluctuations, when the sun-heated bark thaws during the day and freezes again at night. Light spots of irregular shape appear on the southern and southwestern sides of the trunk. In spring, slow bud opening is observed, and in summer, weak growth and drying of shoots are observed. At the end of summer, the bark cracks and falls off, the wood of the affected skeletal branches and trunks dies. Fungal and bacterial infections spread on weakened trees. Very often, the root system of trees freezes completely, and the affected trees dry out at the very beginning of summer.
In most cases, branches and shoots break off under the weight of the first wet snow or heavy snow cover. In some years, branches break under the weight of fruits or strong winds. This also often happens during transportation or when planting trees, especially large ones. Therefore, in the fall, it is better to tie young plants with twine or rope and periodically shake off the snow from them. The first time after planting or transplanting, plants should be tied to a support, this will protect against bending and fractures of the trunks. Any mechanical damage and cuts of trunks and branches should be disinfected with a 1% solution of copper sulfate and covered with paint using natural drying oil. It is in the places where the wood is cut that it cracks and dies, and the trees gradually dry out.
Watch apple tree diseases and their treatment in the video, which shows the basic principles of agricultural technology and tree care at different times of the year:
One of the main tasks of a gardener is to protect trees from pests and diseases.
To obtain a high-quality harvest, this work must be carried out correctly and in a timely manner.
It is a common garden shrub and tree. This disease of fruit trees develops in conditions of high humidity and air temperature +18...+25 degrees.
In such a situation, the apple tree’s resistance to infection decreases sharply.
In summer, when the weather is hot, the powdery mildew coating hardens and turns into a fruiting body, which transforms into a black mushroom.
This stops the spread of the disease. The layering dies, and the infection develops further in the buds of the tree in hot weather.
Who is the causative agent of the disease?
Source of powdery mildew - fungus, which affects all parts of the plant, including bark, leaves, and young buds.
Sign of disease a sticky white coating appears on the apple tree: on new shoots and leaves. This layer, after some time, becomes brown with dark dots.
Affected areas deformed and, curling, fade. The shoots stop growing, curl up and dry out. What powdery mildew looks like on an apple tree is shown in the photo below.
Powdery mildew on an apple tree: 1 - mycelium and condia, 2 - affected parts. Powdery mildew on trees affects the condition of the garden as a whole. Leaves fall from trees prematurely, yield is significantly reduced. Severe frosts reduce development.
Important! The mycelium of the fungus in infected buds disappears at a temperature of -20 degrees. At the end of severe frosts, the signs of the primary disease decrease. The source of the disease dies en masse.
Disease development cycle
The infection development cycle includes two stages:
- Marsupial;
- Directly conidial.
Observable white coating on plant areas is sporulation of conidia. First stage of the disease appears in early spring when buds open. During this period, a shrub or tree becomes infected with a fungus that has overwintered in the ovaries.
Condia appear that serve as a source of secondary infection. The first stage of the disease lasts on average 30 days.
Then at the end of May - beginning of June the marsupial stage begins. It is expressed in the appearance on the shoots and leaves of black fruiting bodies with branched appendages.
Marsupial stage. Downy mildew
Powdery mildew as a disease spreads throughout the plant. Young branches and leaves, inflorescences, and sometimes fruits are affected.
Symptoms of infection appear first on the apple tree. They are covered with a white coating. Diseased areas stop growing, lose color and fall off.
On the branches the infection appears as a white powdery coating. Then it begins to darken, the shoots slow down, become crooked and finally die off. Young branches infected with powdery mildew freeze up to 50% of the total amount.
Inflorescences get sick when the bud separates. The brushes are covered with a white coating of thick consistency, while drying quickly.
The ovary does not have time to form. Infected flowers develop poorly, bloom chaotically, and they themselves become deformed and dry out.
The apples themselves are also susceptible to disease.. Sometimes a young ovary infected with powdery mildew forms a fruit.
With further development, a trace in the form of a net remains on its peel.
Varieties resistant to powdery mildew
When planting your garden, it is advisable to plant varieties of apple trees that are resistant to the infectious agent. Varieties such as:
- Arbat,
- Gold Rush,
- Brigham Delicious,
- Florina.
Advice! By doing this, you can save up to 80% of the garden's harvest.
Causes of the disease
The reasons why the leaves of an apple tree turn white are: it is generally accepted:
- Fog,
- Dew,
- Increased air temperature.
Added to these factors reduced tree resistance and shrubs to disease due to dry weather and lack of moisture.
The combination of these conditions leads to plant infection. The resistance of apple trees to the disease decreases due to sharp fluctuations in air humidity.
The source of infection, due to which the leaves of the apple tree turn white, overwinters in infected buds or as a fruiting body on branches and leaves.
Then condiments are carried by the wind throughout the garden, affecting new healthy trees. In this way, the apple tree becomes infected a second time.
Powdery mildew manifests itself after the tree blooms and recurs several times at the beginning of the growing season. The incubation period of the disease lasts up to ten days th and depends on weather conditions and the resistance of the apple tree to infection.
Fighting methods
Powdery mildew, a chronic disease of apple trees, reduces garden productivity.
The leaves fall prematurely, resulting in the loss of 50 to 80% of the fruit. Therefore, the question is quite relevant if powdery mildew appears on an apple tree: “How to deal with it?”
If, nevertheless, varieties of apple trees are planted in the garden that are susceptible to powdery mildew infection, it is necessary to master some methods to combat it:
- In winter and spring it is necessary regularly cut out diseased shoots. This is done not only during bud break, but also after the tree has flowered.
Important! Cut branches must be destroyed, since the fungal spores are very viable. They can cover a distance of up to 1 km without losing their functions
These operations are aimed at combating the consequences of the disease and do not affect its development.
To protect trees from infection with their fungicides:
- Trees are treated when the buds open, at the beginning of flowering and after it ends.
- The procedure is repeated several times per season.
- Up to 5 treatments of the garden with chemicals are carried out per year.
In hot summer weather, trees are treated more often. Maintain an interval of 6 - 8 days. When planted apple trees resistant to infection, spraying is carried out as the disease is affected. This may be one or two procedures.
It is important to treat with chemicals before the leaves appear. Folk remedies
A set of folk remedies is also used to protect apple trees. These include:
- diseased branches;
- Digging up soil around tree posts;
- Application of phosphorus-potassium;
- Spraying trees with infusions of insecticidal plants.
Soda
Baking soda is an effective way to combat powdery mildew.. There are many ways to prepare a solution. There are no clear proportions here.
One of the infusion options is this:
- 100 gr. Laundry soap is dissolved in ten liters of hot water.
- Add two full tablespoons of soda,
- Stir well.
- Plants are treated with this solution three times every 7 to 10 days.
How to fertilize an apple tree in the fall against disease?
Chemical control measures against powdery mildew is the treatment of plants with such means as:
- Topaz,
- Topsin,
- copper sulfate,
- Colloidal sulfur.
Spray several times with warm solution.
In case of severe powdery mildew infestation resort to special treatment with fungicides based on tebuconazole, penconazole and flutriafol.
In the phase of loosening and dividing the bud carry out the first treatment, the second - after the tree blossoms, and the subsequent ones - twice after 10-14 days.
Special treatment against powdery mildew. Treating the garden against powdery mildew the following chemicals:
- Hom, or copper oxychloride. This is a bluish powder. The product is diluted in a small container. The liquid is then diluted to the required volume. Processed in dry, windless weather. The air temperature should not exceed +30 degrees.
- Tebuconazole. Systemic fungicide that penetrates the plant. Effectively affects powdery mildew infection and protects plants for three weeks after treatment.
- Fitosporin. An environmentally friendly microbiological preparation based on living spores and cells. Trees are treated once every two weeks. Spraying can be done in any weather. In rainy weather, 2-3 hours before the rain starts or 3 hours after.
- Cumulus, or colloidal sulfur. Inorganic fungicide in the form of granules. Used to combat fungi. During processing, the air temperature should not exceed 28 degrees. In hot weather, application is ineffective.
- Urea. This is a nitrogen fertilizer in the form of granules. To feed trees, dissolve 200 grams in 10 liters of water.
- Impact. Fungicide against fungi of low toxicity. It is advisable not to use during flowering plants. The drug protects the plant for up to 30 days. Used both in early spring and late autumn.
Prevention measures
Mandatory application of fertilizers. A preventive measure in the fight against powdery mildew in the garden is proper planting of the garden. Choose for infection-resistant apple tree varieties.
Apply throughout the season agrotechnical activities in the garden, providing for trees:
- They try to prevent the crown from becoming too thick;
- Maintaining optimal humidity levels in the garden;
- Timely destruction of infected shoots;
- Destruction of fallen leaves;
- Digging of tree trunk circles is carried out.
In conclusion we can cite Some tips for combating powdery mildew in apple trees:
- Carrying out zoning in the garden and selecting tree varieties.
- Using chemical treatments for trees in late autumn after leaves fall.
- Maintaining constant humidity in the garden, which makes the trees more resilient.
- Spraying trees with chemicals.
Useful videos
Watch the video to see what powdery mildew is on an apple tree:
Watch a video from an expert about the causes and methods of combating powdery mildew:
Watch the video for expert advice on the fight and prevention of powdery mildew:
Watch the video on how to eradicate powdery mildew without chemicals:
By following all the tips and methods for combating powdery mildew, you can grow a good garden and get an excellent harvest.
The most common disease that significantly reduces the yield of fruit trees is powdery mildew. Heat-loving plants grown in temperate climates are at risk, but with uncharacteristic temperature conditions for the region and increased average annual humidity, powdery mildew also appears on apple trees, the most traditional fruit tree in the temperate climate zone.
Fungal disease of garden fruit trees, shrubs, and root crops has several names, the most common are:
- underwear;
- powdery mildew;
- Ashtray.
What looks like a white coating on leaves, flowers, and fruits is the mycelium of microscopic fungi that multiply exponentially; every day a colony of pathogenic fungi covers larger and larger surface areas of leaves, bark and other outer parts of the plant.
The spores are easily carried by wind and insects, which means that if one tree in the area becomes diseased, it 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 damage in the fight against this scourge it is possible to save most of the crop, then if the apple tree is diseased at the stage of fruit ripening, losses can amount to up to 80% of the crop.
Who is the causative agent
The causative agent of powdery mildew is the marsupial fungi of the order Erysiphaceae (erysyphaceae), there are more than 700 species that cause powdery plaque - 100. Erysiphe, which causes Oidium, also belongs to this class.
The mycelium of the fungi that causes the disease is superficial with appressoria (suckers). To attach to the leaves, the fungi grow into plant cells with short hyphae with haustoria. During the growing season of the plant, fungi reproduce by conidia (asexual stage); in tropical climates, this may be the only stage. Conidia are arranged in islands or chains.
In a temperate continental climate, fungi have 2 stages of development - asexual and sexual (marsupial).
Like all mushrooms, Erysifaceae have fruiting bodies - cleistothecia. The spherical mushroom with a concave tip has appendages in the form of simple or branched outgrowths. Each of them contains from 1 to 22 asci; 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 if preventive and therapeutic measures are not taken in time.
Distribution area
The mycelium of marsupial fungi that cause leucorrhoea does not tolerate severe frosts; the mycelium can overwinter provided that it is located deep in the bark of a tree damaged in the previous season. Based on the harsh climatic conditions - severe frosts, short, dry, hot summers, fruit trees grown in Siberia and other northern regions are least often affected by powdery mildew.
Almost powdery mildew on fruit trees can be found in any corner of the world; the largest areas affected are observed in countries with a temperate continental climate.
The higher the air and soil humidity, the fewer sunny days in summer, the higher the risk. The most favorable conditions for the spread of pathogenic fungi are the Baltic states, the northwestern 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, and Moldova.
Main causes and factors in the development of the disease
Between plants, the disease spreads conidially, methodically capturing more and more new areas on the leaves and bark of the infected tree and neighboring drupes, berries, fruit trees and shrubs.
A favorable environment for mycelium is created by:
- soils with poor water conductivity;
- lack of sunlight at high air temperatures;
- mild winters with thaws;
- warm, swift spring after a snowy winter.
Under such natural conditions, the mycelium will develop quickly. At the spore maturation stage, winds and heavy rains will facilitate the reproduction and transmission of the disease.
Signs of tree infection
A white translucent coating formed on the shoots and leaves at the stage of appearance of the first leaves is a sign of the manifestation of the disease. At the same time, the buds that have not yet blossomed begin to wither, become deformed, turn brown, wither and fall off.
The affected areas only initially appear white; the development of the disease is indicated by a denser silvery coating, which appears as such due to the formation of cleistothecia.
At first these are rare black dots; at a later stage, the fungal coating acquires a brown tint. The white coating on fruits is a short-term phenomenon. Apples affected by the fungus develop brown, woody spots and streaks on the skin.
What is dangerous for a tree
The mycelium of fungi that causes powdery mildew on apple trees most often does not survive the winter, but under favorable reproduction conditions it can destroy an immature young seedling due to the compaction of the mycelium. Mature apple trees with chronic mildew stop bearing fruit long before the end of the typical period for the variety.
Please note: the incubation period is 4-9 days.
Preparations for powdery mildew on apple trees
A universal remedy for fungal infections and insect pests of fruit trees is colloidal sulfur. The trees are sprayed with a two percent solution during the budding period, until the cup of flowers opens. At the end of flowering, for preventive purposes, treatment is carried out with a one percent composition.
When treating with a universal fungicide - Bordeaux mixture, take a 3% solution for the first spraying, and 1% for the second. To effectively protect apple trees from re-infection, the penconazole drug “Topaz” is recommended; it penetrates deeply into the tissues of the tree and fights the pathogen from the inside, and not just the superficial manifestations of the disease.
Just like Topaz, the following are in demand among gardeners:
- granular urea;
- "Impact"
- "Cumulus";
- "Tebuconazole";
- "Topsin";
- "Fitosporin".
If you don’t have specialized chemicals on hand, there are several options for treating your apple tree when the first signs of ash fly are detected.
Folk remedies
Three simple recipes have been used effectively by amateur gardeners for a long time. Recommended proportions for 10 liters of water:
- 50 g of soda ash with 40 g of grated laundry soap.
- 3 g potassium permanganate (potassium permanganate);
- "Hom" - copper oxychloride, 40 g.
These products, in combination with fertilizing, give a good preventive effect; if the disease manifests itself, such spraying gives the gardener a reprieve for 3-4 days. Severe lesions must be treated with specialized means. Sometimes it makes sense to sacrifice the harvest of one season in order to protect the tree.
Control measures
Prevention at the stage of the initial growing season is important, but how to deal with powdery mildew during fruit ripening? Folk remedies do not affect the quality of the fruit; if there is an increased risk of plant infection with powdery mildew, it is recommended to spray apple trees with potassium permanganate or a solution of soda with laundry soap once every 10-14 days.
If the tree is infected, the manifestations of the disease are not only on the leaves, but also on the branches and trunk, then you cannot do without Topaz or a fungicide similar in action to it. The first 2 sprayings are carried out at intervals of 3-4 days. Further, until the fruits ripen, it is necessary to carry out prevention.
Treatment of an adult tree
Treating a tall apple tree with a dense crown is difficult; spraying is carried out not only on the surface of the leaves; it is necessary to treat the branches, trunk, and lower part of the leaves. To do this, you will need an assistant pumping the solution and personal protective equipment - glasses, a suit that maximally protects areas of the body.
What to do with an apple tree when an entire branch of an adult plant is affected? It is easier to remove and burn it; in such a case, a stepladder, pruning shears, hacksaw, and garden pitcher should always be at hand. To prevent the development of powdery mildew after winter from mycelium that has overwintered in the soil:
- Mulch is removed from under the tree.
- In spring and autumn, the trunk is whitewashed.
- There should not be any last year's leaves or fruits on the site.
Manifestations of the disease on apples do not affect the taste, but the apples will be less juicy. If pathogens can be overcome using folk remedies or gentle dosages of chemicals, then the crop can be used for food.
Attention! You can find out after what treatments apples are suitable for eating on the packaging of professional products. The manufacturer's instructions will be relevant if the recommended proportions are strictly observed during use.
How to save young seedlings
To protect apple tree seedlings during the planting season, they are soaked for a day in a weak solution of potassium permanganate (potassium permanganate). The water should acquire a light pinkish tint; a strong solution can cause burns and the plant will hurt. To improve the survival rate of a seedling, it is better to use growth stimulants, and it is better to refuse nitrogen fertilizing, because in the first season a harvest is not expected from an apple tree (on any rootstock).
Prevention
When selecting a site for planting, you should avoid proximity to plants affected by the fungus, protect it on the leeward side, but do not plant it in the shade of a house or a monolithic fence. It is imperative to adhere to the intervals recommended for specific heights of fruit trees.
It is necessary to thin out the crown, remove affected and old (non-fruit-bearing) branches, remove fallen leaves and fruits, carry out mulching and whitewashing, and apply potash and phosphorus fertilizers.
How to fertilize an apple tree in the fall against disease?
A 1-1.5 percent solution of sodium phosphate strengthens the plant, helps to establish the formation of strong, healthy buds, and strengthens the plant’s immunity to diseases.
Seasonal processing
Phosphate spraying is carried out on apple trees and other fruit trees after harvesting, but before the leaves have fallen and turned yellow. The solution is absorbed through the leaf blades, thereby protecting the plant from infection by powdery mildew and other fungal diseases after winter.
On varieties of late-ripening apple trees, the leaves fall off before the tree is harvested; in this case, phosphate must be applied through the soil with the last watering of the season. Thinning the thickening tree crown prevents the rapid spread of the disease; whitewashing the trunk makes it difficult for hyphae and haustoria to penetrate the plant bark.
Varieties resistant to powdery mildew
The resistance of an apple tree to certain strains of diseases in plants, as in all living organisms, is determined by a gene that is strongest in apple trees of selected varieties:
- Amulet;
- Argo;
- Gloucester;
- Duet;
- Marshmallow;
- Golden summer;
- Carmen;
- Red poppy;
- Red amber;
- Kupava;
- Linda;
- Mutsu;
- Orion;
- Palette;
- Prestige;
- Dawn;
- Redfree;
- fontanel;
- Union;
- Talida;
- Mascot;
- Fortune;
This is not a complete list of apple trees resistant to powdery mildew. For each region, other varieties with high resistance rates can be found in local nurseries. When choosing an apple tree variety, it is necessary to remember that immunity to one disease in an apple tree can be compensated by weak resistance to other types of pathogens.
If the disease is severely 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 formed (they dry out and fall off just like the fruits). Powdery mildew also affects the winter hardiness of trees: infected shoots and buds have time to die over the winter.
Symptoms
Mycosis affects all organs of the apple tree. This also applies to other fruit trees. Symptoms become noticeable as early as April, and sometimes March. At first, the coating on the shoots is whitish or has a silvery tint. Later it becomes gray-brown and subsequently darkens. You can find dark spots on it - these are the spores of the fungus and its fruiting bodies, also known as cleistothecia.
The petioles and leaves are covered with plaque on the underside. Then it becomes rusty brown in color. The leaves stop their development, curling into a tube along the central veins. In the same way, the buds of an apple tree and its flowers crumble and wither. The fungus spores for about three months and this is enough to destroy the crop.
The plaque appears on the apples themselves when they just begin to form. Afterwards it disappears, leaving only a brown mesh, similar to cork tissue, that appears on the fruit after any mechanical damage. By the way, in the early stages, plaque from fruits and leaves is easily removed, but appears with a vengeance after it is removed, acquiring a purple tint.
The inflorescences acquire a green-yellow color. They are developmentally delayed. Flowers do not appear at the same time, but at different times; both stamens and pistils may be deformed.
Powdery mildew is widespread mainly in Kazakhstan, the North Caucasus, Central Asia, as well as in southern Russia, Moldova and Ukraine. In Georgia and the Krasnodar Territory, as well as in Kyrgyzstan, the infection rate of apple trees is slightly lower. Much less common in the Volga region and the Baltic states.
Preventive measures
Powdery mildew must be prevented from the earliest stages of tree life. Do not forget to ventilate the room where the seedlings grow. It is also necessary to protect apple tree seedlings from drafts and not exceed normal air humidity.
As a preventative measure, apple trees should also be sprayed with Bordeaux mixture or any fungicides. We do this three times.
It will be no less effective to pollinate the trees with sulfur three times during the summer. Fertilizing with phosphorus or potassium fertilizers also strengthens immunity to fungus. But nitrogenous fertilizers will increase the risk of developing this mycosis.
How to deal with it
The disease is dangerous and devastating, so we must fight it seriously. First of all, watering should be moderate, and the soil moisture should be constantly monitored. This will increase the hardiness of the apple trees. But among the chemicals the most effective are the following:
- Colloidal sulfur. This is a leader among fighters against powdery mildew. It also copes with plant mites, scab, ascochyta blight and anthracnose. Treatment with it should begin when buds are just appearing on the trees. To begin with, a two percent solution will be enough (take 20 g of colloidal sulfur per 10 liters of water). Next, spray with a one percent solution. The third time - after two or three weeks and no later than three weeks before picking the 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 tree well: the solution should flow down them.
- Bordeaux mixture. It also has a wide spectrum of action. It copes with downy mildew, scab, spotting, and sulfur rot. In March-April we spray the apple tree with a three percent solution, and during the growing season with a one percent solution.
An adult tree needs up to 10 liters of solution, a young tree - about two. Don't forget to process the barrel. A healthy apple tree should be treated with this liquid once every three years.
- Topaz. The active substance is penconazole. The product does not allow the fungus to sporulate. Quite economical and not toxic to the plant at all. For 10 liters of water you need about 15 ml of product. We process two to three times.
- Soda ash. We need it for 10 liters of water, about 50 g. We also add laundry soap (40 g).
- We take about 3 g of potassium permanganate per 10 liters of water; We process three or four times in a row.
- Copper oxychloride may also be effective. We take it for 10 liters of water, 40 grams.
Powdery mildew is a very dangerous and destructive disease. The main thing when fighting it is not to overlook the very first symptoms of mycosis. Prevention and control should be regular. One treatment will not be enough.
Apple powdery mildew
Pathogen: mushroom - Podosphaera leucotricha Salm.
Class: Ascomycetes - Ascomycetes
The harmfulness of the causative agent of powdery mildew in apple trees
The disease is widespread everywhere. It affects almost all plant organs, leaves, inflorescences, shoots, and less often fruits.
Symptoms of powdery mildew in apple trees
Symptoms of the disease appear first on young foliage. Infected plant organs are covered with a gray-white cobwebby powdery powdery coating. Affected foliage stops growing, curls, turns brown and dies prematurely and falls off.
At the beginning of the development of the disease, infected shoots become covered with a white coating. Over time, this plaque begins to darken. The shoots slow down in growth, bend and die over time. Inflorescences are affected even in the bud separation phase. The peduncles and the flowers themselves become covered with a thick whitish coating and quickly dry out, but the ovary does not form.
On fruits, powdery mildew appears in the form of a rusty mesh, which looks like mechanical damage. The infected ovary soon falls off. The disease causes enormous harm in nurseries, affecting seedlings and saplings.
Biology of the causative agent of powdery mildew in apple trees.
The causative agent of the disease is powdery mildew Podosphaera leucotricha Salm. The development cycle of the pathogen consists of two stages - conidial and marsupial. The white coating on infected plant organs is nothing more than conidial sporulation.
In the third ten days of May - the first ten days of June, as a rule, the marsupial stage appears on the affected shoots, sometimes on fruits and leaves. The marsupial stage appears as black dots (fruiting bodies) equipped with branched appendages at the tips. The fruiting body consists of one sac, which contains eight sacspores.
The disease development cycle has 2 types of infection – primary and secondary. In the spring, during the budding phase, a primary infection appears as a result of infection by a fungus that has overwintered inside the buds. During the primary manifestation of the disease, conidia appear, which are the source of a new infection and, accordingly, a secondary infection. This period lasts from 15 to 45 days.
Hot weather, heavy dew and fog are favorable for the development of powdery mildew. Plant resistance to the disease decreases in dry weather and when there is a lack of water in the soil. Under such conditions, plants are affected much more quickly by powdery mildew. Also, sharp fluctuations in humidity have a very negative effect on the resistance of apple trees to powdery mildew.
The pathogen usually overwinters in the form of mycelium in the affected buds, but the pathogen can also overwinter in the form of fruiting bodies (marsupial stage) on stems or on fallen leaves.
Measures to combat apple powdery mildew
Agrotechnical control measures
- proper care of plants in the garden, which ensures normal plant development;
- maintaining optimal humidity in gardens with irrigation;
- identification and destruction of sources of infection, timely pruning and burning of affected shoots;
- recycling of fallen leaves;
- between the rows it is necessary to plow and dig around the tree trunks;
- growing powdery mildew-resistant apple varieties.
Chemical control measures
It is recommended to spray with fungicides. During the phase of loosening and separation of buds, it is recommended to carry out the first spraying, the second - immediately after flowering, the next 2-3 sprayings should be carried out at intervals of 10-15 days, with the following fungicides:
- Horus 75, V.G. – 0.2-0.25 l/ha – during the growing season 4 sprayings should be carried out every 10-14 days;
- Tsideli Top 140, cd – 0.6-0.7 l/ha – spraying is carried out according to a similar scheme, but with a doubling frequency;
- Tiovit Jet 80, v.g. – 8.0 l/ha – spraying frequency 4, every 10-14 days;