Powdery mildew in maples. What is powdery mildew and how to fight it How to cure oak from powdery mildew

Powdery mildew is a rapidly spreading fungal plant disease. Initially, a white powdery coating appears on the leaves, similar to flour or powder. It can be easily wiped off with your finger and even mistaken for ordinary dust. But it was not there! Before you know it, this infection will appear again, and in greater numbers, capturing ever new areas of habitat. Not only the leaves become white, but also the stems and flower stalks. Gradually, old leaves turn yellow and lose turgor. New ones grow ugly and twisted. If measures are not taken to cure powdery mildew, the plant will die.

This is what powdery mildew deposits look like when zoomed in:

Ulcers at the site of mycelium formation

Powdery mildew disease: where does it come from?

The weather outside is cool (15.5-26.5°C), damp (humidity 60-80%), cloudy (for example, during the rainy season). Weather conditions have a particularly great influence on outdoor and balcony plants; when grown in rooms they are not so noticeable;
there is a large amount of nitrogen in the soil;
plantings are thickened;
The watering schedule is not followed. For example, a plant is often watered without waiting for the top layer of soil to dry. Or, on the contrary, they regularly dry out the earthen ball and then fill it with water. All this leads to impaired immunity and, as a consequence, the appearance of powdery mildew.

In addition to these external conditions, already “awakened” spores can end up on flowers:

by air (from infected trees or plants);
through irrigation water (if spores got there);
through your hands (if you touched an infected plant and then touched a healthy one).

Powdery mildew can completely destroy a plant in a short time

Proper agricultural technology is an important condition in the fight against powdery mildew

The fight against powdery mildew is an integrated approach. First, you need to put in order the agricultural technology for growing the affected plant. This means:

watering only after the top layer of soil has dried;
while fighting powdery mildew, completely stop spraying;
if possible, move the affected specimen to a brighter, sunny place until the powdery mildew is cured;
thin out thickened plantings, tear off old leaves that touch the ground;
for the period of remission - less nitrogen fertilizers, more phosphorus-potassium fertilizers (in case of illness - no fertilizers at all).

All errors in care must be corrected, otherwise powdery mildew will appear regularly. Now let's talk about direct treatment.

How to fight powdery mildew: therapeutic spraying and watering

To get rid of powdery mildew, do the following:

Tear off the affected (yellow, lacking turgor) leaves and all flower stalks. If powdery mildew appears on roses, petunias, chrysanthemums and similar bushy plants, it is advisable to carry out radical pruning. The more damaged branches are destroyed, the greater the chance of recovery;
replace the top layer of soil in a container, pot or under a plant in a flower bed - entire colonies of mushroom mycelium are hiding there;
carry out therapeutic spraying and watering of the plant with one of the medicinal preparations. When spraying, you should strive to wet all the leaves and shoots abundantly. The plant should pour like after a spring shower. There is a more effective way: pour the medicinal solution into a basin and dip the bush into it. The soil is also generously moistened with the solution by spraying with a spray bottle or watering. The walls of pots and pallets are also processed.

Powdery mildew: folk remedies

Let’s make a reservation right away: folk remedies for powdery mildew are effective as a preventive measure or in the initial stages of the spread of the disease. If the destructive process started a long time ago, more than 5-7 days ago, it is already useless to fight in this way. It may be possible to stop the development of the disease, but not completely eliminate it.

The most famous and effective folk remedies for powdery mildew are prepared as follows:

1. From soda ash and soap

25 g of soda ash is dissolved in 5 liters of hot water, add 5 g of liquid soap. Spray the plants and top layer of soil with a cooled solution 2-3 times at weekly intervals.

A protective preparation against powdery mildew is prepared from soda ash and liquid soap (preferably laundry soap)

2. Baking soda and soap

Dissolve 1 tbsp in 4 liters of water. l. baking soda and 1/2 tsp. liquid soap. Spraying is performed 2-3 times with an interval of 6-7 days.

3. Potassium permanganate solution

2.5 g of potassium permanganate is dissolved in 10 liters of water and used 2-3 times with an interval of 5 days.

4. Whey solution

The serum is diluted with water 1:10. The resulting solution forms a film on the leaves and stems, which makes it difficult for the mycelium to breathe. At the same time, the plant itself receives additional nutrition with useful substances and becomes healthier, which affects the improvement of its appearance. Treatment with whey solution is carried out in dry weather, at least 3 times, with an interval of 3 days.

5. Horsetail decoction

100 g of horsetail (fresh) is poured into 1 liter of water and left for 24 hours. Place on fire and boil for 1-2 hours. Filter, cool, dilute with water in a concentration of 1:5 and spray the bushes. The concentrate can be stored in a cool, dark place for no more than a week. Spraying with horsetail can be carried out regularly to prevent powdery mildew in the spring and summer. In the fight against an existing disease (in the initial stage), 3-4 times spraying every 5 days is effective.

6. Copper-soap solution

This remedy for powdery mildew is highly effective due to the inclusion of a well-known fungicidal drug - copper sulfate. 5 g of copper sulfate are diluted in a glass (250 ml) of hot water. Separately, dissolve 50 g of soap in 5 liters of warm water. After this, carefully pour the solution with vitriol into the soap solution in a thin stream and with constant stirring. The resulting emulsion is sprayed on plants 2-3 times with an interval of 6-7 days.

7. Mustard solution

Mix 1-2 tbsp into 10 liters of hot water. dry mustard. The cooled solution is good for both spraying and watering.

8. Ash + soap

Stir 1 kg of ash in 10 liters of heated (30-40°C) water. The solution is infused, stirring regularly, for about 3-7 days. Then pour the liquid component (without the ash suspension) into a clean bucket, add a little liquid soap, pour it into a sprayer and carry out the treatment. Spray the plants every day or every other day 3 times. Add 10 liters of water to a bucket with ash particles that have sunk to the bottom, stir and use it for irrigation.

9. Infusion of rotted manure (better than cow manure)

Fill the rotted manure with water in a ratio of 1:3 and leave for 3 days. Then dilute the concentrate twice with water and spray the bushes.

10. Garlic infusion

25 g of garlic (chopped) are poured into 1 liter of water, kept for 1 day, filtered and sprayed on the collection.

Powdery mildew: treatment with chemicals

If powdery mildew appears on your flowers, combating it is most effective with the help of modern fungicidal agents. They have a detrimental effect on the fungus, stop harmful processes in plant cells, protect and treat it. Spraying is carried out 1-4 times with an interval of 7-10 days (depending on the selected drug).

Chemicals for powdery mildew act quickly and effectively

The most effective drugs for powdery mildew:

Fundazol;
Topaz;
Acrobat MC;
Previkur;
Speed;
Vitaros;
Amistar extra.

A well-known fungicidal drug is phytosporin, the active ingredient of which is a concentrate of the bacteria Bacillus subtilis in a powder of chalk and humates. Despite the fact that phytosporin is considered a medicinal agent, it is practically useless against existing powdery mildew. However, as a preventive measure, it will work flawlessly.

One of the favorite crops for landscape design is maple - the owner of beautiful dissected leaves located on long petioles. However, all the decorative properties of the plant can be destroyed by powdery mildew.

What is powdery mildew?

Also called ash and white, it is a common fungal disease. It is characterized by a white coating on the leaves and deformation of the leaf plate. As the disease spreads, the maple leaves dry out and fall off.

Infection most often occurs in early summer. This time is the period of activation of the fungus after wintering. Hot weather, strong fluctuations in humidity and temperature weaken the maple's immunity.
How to protect crops from fungus? Protective measures should be taken in advance.

Prevention

The main preventive method to prevent powdery mildew from infecting a tree is proper maple care:

timely pruning;
burning of plant debris that forms under the crown and is a wintering site for the fungus;
balanced application of fertilizers (excess nitrogen increases the risk of damage).

It is not always possible to prevent infection; the only way to save a culture is treatment.

Treatment

There are several options for getting rid of fungus. The most effective method is spraying with biological and chemical fungicides - antifungal drugs.

These include Skor, Fitosporin-M, Falcon and many others. Treatment is carried out twice, with an interval of 2 weeks. The entire crown should be processed, which is not feasible for tall varieties (for example, Norway maple).

A less effective way is to spray with folk remedies - soda, laundry soap and other improvised substances. They do not guarantee a quick cure, but can be a temporary measure in the absence of chemicals.

Treating maple for powdery mildew is a long and thorough process, so it is better to prevent the appearance of fungus by regularly carrying out preventive measures.

Powdery mildew, one of the most common plant diseases, has not spared the mighty oaks. Because of it, the leaves become whitish, lose their ability to photosynthesize and fall off, and the tree is left without the nutrients it needs. What to do? In forest conditions, ridding plants of powdery mildew is the concern of foresters, and in planting near the house, the owners deal with this problem, using both folk remedies and chemicals from stores.

How to recognize the disease?

What signs indicate that a tree is affected by powdery mildew? In spring and summer, a white coating appears on the leaves, similar to flour or white dust - this is the first sign of a problem that is not always immediately noticeable.

The next stage is when the white coating develops into white mold, that is, the fungus has affected not only the leaves, but also the trunk. This indicates that the tree is gradually dying. Powdery mildew attacks trees of any age, but young oaks under 30 years old are more likely to get the disease, especially if they are weakened by other problems and diseases and grow in unfavorable conditions. Older specimens may not get sick at all, or they tolerate the disease quite steadfastly and live with it for many years. However, the leaves from these trees must be burned in the fall, otherwise the disease will spread to other plants.

Young shoots that have been exposed to spring frosts are especially susceptible to infection; it is them that the disease attacks first. Powdery mildew also develops well on trees growing in dense, heavily shaded areas, as well as on soil with stagnant melt or rainwater.

Treatment methods

Powdery mildew is a fungal disease, which means it needs to be combated with the help of fungicides such as Quadris, Gamair, Topaz, Jet, and others. All of them are supplied with instructions for use; it is very important to follow all of its instructions exactly. It is also necessary to take care of your own protective equipment - glasses, a respirator, a hat, and closed clothing.

If you are not familiar with any drug, have never worked with it before, and do not know how trees will react to it, first spray several branches on one tree; if they tolerated the procedure well, proceed to treat the rest.

It is no secret that chemicals are harmful to both humans and the environment. Their use is not always justified, especially if there are residential buildings nearby, fruit trees or berries grow, or dogs and cats run around.

There are also several folk remedies with which you can forget about such a problem as powdery mildew on oak for a long time. Especially if you work proactively and spray the trees at a time when the disease is not yet present.

Make a solution of 1 kilogram of wood ash and 10 liters of water at room temperature. The solution must be infused for about 5 days, stirring constantly. Then drain through cheesecloth into a clean bucket, add a little laundry soap dissolved in water so that it sticks well to the leaves. When spraying, you need to try to cover all the leaves; to do this, you need to attach a ladder to large trees.
A solution of fresh manure also helps cure trees of powdery mildew. Take a third of the bucket, fill it with water to the top and leave it for 3 days. Then filter and pour into a separate container. The resulting solution should be added to water at a rate of 1x10 and sprayed on the tree in the evening.
Soda ash, soap and water prevent the formation and spread of powdery mildew. The solution is made from 4 grams of soda, 4 grams of laundry soap, and 1 liter of water. They are mixed until completely dissolved and used for spraying once a week. In total you need to do 2 sprays.
Sour dairy products - their bacteria destroy powdery mildew fungi without causing any harm to oak trees and other plants. The curdled milk is diluted with water in a ratio of 1x10, mixed well and immediately sprayed on the tree.

Non-communicable diseases. The leaves turn brown, starting from the edges, curl and dry out. Norway maple gets sick more often than others. Reason: soil salinity or irregular watering.
Control and prevention measures: Recultivate the soil or provide regular watering of plants.

Leaf spotting. There are two types. First option: Rounded light brown spots appear on the leaves. Second option: Chaotic brown spots form on the leaves, including along the edges. Necrotic tissue tears.
Control and prevention measures: Carefully remove fallen leaves where the pathogen remains. Boost plant immunity. In case of severe damage, the following fungicides can be used: Bordeaux mixture and Abiga-Pik.

Tar spotting. Yellowish spots appear on the leaves, then black shiny blots with a yellow rim.
Control and prevention measures: Destroy the affected leaves. Provide plants with enough light and air. Thin out thickened plantings.

Sycamore leaf spot. Light brown spots with a dark rim appear on the leaves and grow up to 2-5 cm in diameter. The leaf veins darken. Small fruiting bodies are visible on them.
Control and prevention measures: The fungus spreads quickly when the air humidity is high and the leaves are damaged. Affected parts of plants are removed if possible. To make the leaves dry out faster, reduce air humidity. In the fall, plants are allowed to properly prepare for winter. In case of severe damage, the following fungicides can be used: Bordeaux mixture and Abiga-Pik.

Verticillium wilt. Leaves on some branches wither. Brown vessels are visible on the cut of the stem. The roots are not damaged.
Control and prevention measures: Affected plants are destroyed. Verticillium-prone plants are no longer planted at the site of fallouts.

Coral spotting. Pink or cinnabar-red fruiting bodies the size of a pinhead appear on branches and trunks. The fungus settles on dead tissue (for example, in cracks in the bark), causes the death of neighboring tissues and gradually penetrates deep into the plant.
Control and prevention measures: Dead branches are removed, and any debris that has formed is removed from under the trees. The cut areas are covered with garden pitch. In case of frequent outbreaks of the disease, it is recommended in the fall, after leaf fall, to spray the trees with copper preparations.

Powdery mildew. A white powdery coating forms on the upper and lower sides of the leaves. The disease also affects flowers. The plant tissues under the coating are brown in color.
Control and prevention measures: Choose varieties that are resistant to powdery mildew. For mild damage, you can try the biological fungicides Fitosporin-M, Alirin-B. In case of severe damage, treat with Topaz, Strobi, Thiovit Jet, Skor, Chistotsvet.

Spider mite. Depending on the type of mite, reddish or yellowish speckles may appear on the leaves, and later extensive red or discolored and dried areas. Severe mite infestation can cause leaves to fall. Small (0.2-0.5 mm) mites live on the underside of leaves among the cobwebs. The appearance of mites is favored by high temperatures and dry air.
Control and prevention measures: For mild damage, you can treat the plants with soap or mineral oil. For severe cases, treat with Bitoxibacillin, Fitoverm, Akarin, Vertimek, Molniya, Fufanon, Kemifos, Karbofos-500, Ditox, Bi-58, Karate Zeon, Kung Fu, Antiklesch, Iskra-M, Actellik, Omite, Tiovit Jet, Zolon, etc.
Photo by Joseph O'Brien.

Gallic flares. Numerous greenish-yellow or yellow-red growths appear on the leaves and sometimes on the shoots.

Control and prevention measures: Affected leaves and shoots are immediately removed.
Photo credit: Cheryl Moorehead, Petr Kapitola.

Aphids. Leaves, buds and flowers curl, turn yellow, and when severely infested, sticky secretions of aphids are visible on them.
Control and prevention measures: On single plants or with weak aphid infestation, wash off with water and soap solution; in case of severe damage, they are treated with Antitlin, Tobacco dust, Actellik, Fitoverm, Akarin, Aktara, Decis, Tanrek, Iskra, Zubr, Biotlin, Komandor, etc.
Photo by Joseph Berger.

Diseases of plant leaves.

Poplar rust (Melampsora populina Kleb.).

A disease of plant leaves, the primary infection causes aecidiospores that form on the leaves and needles of the intermediate host. The fungus develops inside the leaf blade. In summer (June), yellow or orange uredopustules appear on the underside; they form several times during the summer, which contributes to the infection of other plants. When plants are severely damaged, uredospores may appear on the upper side of the leaf and on non-lignified shoots. The affected leaves turn black, curl and fall off; telytospores overwinter on them, which germinate in the spring and infect an intermediate host.

spatial isolation between poplar, larch and pine plantings; spraying trees against diseases (fungicides).

Birch rust (Melampsoridium betulinum Kleb.).

A disease of plant leaves that spreads on the underside of the leaf; orange uredospore pads appear in the summer and are replaced by telytospores in the fall. The leaves turn yellow and fall off. The fungus overwinters on fallen leaves; in the spring, larch needles, which are an intermediate host, become infected with basidiospores. Larch aecidiospores infect birch. The disease causes premature leaf fall, retards growth and lignification of shoots.

Methods of combating plant leaf diseases: spatial isolation of birch and larch; spraying plants against diseases with fungicides.

Powdery mildew.

Powdery mildew usually affects young leaves or non-woody shoots. Weakened plants get sick more often. Wet weather and warm summers stimulate the development of powdery mildew, but the plant disease also develops in dry regions. Deciduous trees suffer greatly from powdery mildew: oak, birch, ash, fruit crops, etc.

Oak powdery mildew (Microsphaerd alphitoides Grif).

Infection of oak leaves with powdery mildew occurs by sacspores and vegetative mycelium. On leaves affected by the disease, a white powdery coating appears on both sides, consisting of mycelium hyphae. Later, when conidia form, the plaque becomes denser and more powerful. Ripe conidia cause secondary infection of leaves and shoots with the disease. At the end of summer, fruiting bodies - cleistothecia - of a brown, almost black color appear on the leaves, which overwinter.

In sick plants, the chlorophyll content decreases, the process is inhibited photosynthesis, respiration (gas exchange) and transpiration are disrupted. The shoots ripen poorly and are often damaged by frost.

Methods of combating plant leaf diseases: destruction of fallen leaves in plantations, which are a source of infections; when the first signs of the disease appear, it is necessary to spray plants against diseases with fungicides; spraying plants against powdery mildew is carried out after 10-15 days several times during the summer; Systemic drugs are the most effective.

Maple powdery mildew is caused by the fungi Uncinula aceris Sacc. A white powdery coating appears on the affected leaves due to the growth of mycelium. The disease is infected by conidia in the summer, and brown cleistothecia appear in the fall.

Methods of combating plant leaf diseases: the same as with oak powdery mildew.

Powdery mildew of apple and pear trees (Podosphaera leucotricha Salm.) sometimes appears on leaves, shoots and flowers in early spring in the form of a white coating. The leaves turn brown, curl, and the flowers fall off. The fungus overwinters on shoots and fallen leaves.

Methods of combating plant leaf diseases: spraying apple and pear trees with fungicides in the spring.

Leaf spotting.

Leaf spot is a plant disease caused by various phytopathogenic fungi, bacteria, viruses, as well as unfavorable environmental factors. Individual sections of tissue die, color, structure, shape change, i.e. various spots appear.

White spotting of poplar leaves (septoria).

This plant disease is caused by the fungus Septoria populi Desm. In summer, small light gray, sometimes white spots of varying sizes with a reddish-brown border appear on the leaves. On the surface of the spots there are black dots - fungal pycnidia. The conidia ripened in the pycnidia are carried by wind and water and infect the leaves.

Methods of combating plant leaf diseases: collection and composting of fallen leaves; spraying plants against diseases in early spring with eradicating fungicides, as well as spraying plants during the growing season.

Black spotting of maple leaves.

Black spot of maple leaves is caused by the fungus Rhytisma acerinum Fr. In mid-summer, light spots appear on the leaves; black spots appear in the fall. tar spots with a yellow border. Conidia form on them. On fallen leaves, marsupial sporulation is formed - apothecia, which are a source of infection, so fallen leaves must be burned.

Methods of combating plant leaf diseases: the same as with white spotting of poplar.

Red-brown spotting of cherries (coccomycosis).

The causative agent of the disease is the fungus Coccomyces hiemalis Higg. It affects the leaves and stalks of cherries and cherries, and to a lesser extent apricots, plums, and cherry plums. Dark red angular spots appear on the upper surface of the leaves. The leaves turn yellow and fall off. The quality of the fruit deteriorates. Pink conidia appear on the underside of the leaf and infect other leaves. The fungus overwinters on fallen leaves.

Methods of combating plant leaf diseases: destruction of fallen leaves; in early spring, before the buds swell, eradicating spraying of fruit trees; spraying fruit trees with fungicides in summer; repeated spraying of fruit trees with fungicides after 10-15 days; in the nursery there are 6-7 treatments of fruit trees during the growing season.

Willow scab.

The causative agent of willow scab is the marsupial fungus Venturia chlorospora (Ces.) Wint. In spring, the affected leaves wither, turn black and die. The disease spreads from dead leaves to the shoot, causing its deformation and blackening. Conidia of the fungus formed near the veins of dead leaves are a source of infection. The fungus overwinters on fallen leaves. Wet weather in spring and summer stimulates the development of the disease.

Methods of combating plant leaf diseases: cutting and destroying affected shoots, destroying litter; early spring spraying of trees willow fungicides; in the summer, when the first signs of the disease appear, it is necessary to re-spray the willow trees.

Apple scab (Venturia inaequalis (Cooke) Wint).

Apple scab affects leaves, cuttings, stalks, flowers, shoots and fruits. A green-brown coating of fungal sporulation appears on the leaves, and flaky spots appear on the shoots. Affected leaves and fruits of the apple tree fall off, shoots die, and fruits crack. The fungus overwinters on fallen leaves and becomes infected already in the first half of summer.

Methods of combating plant leaf diseases: destruction of fallen leaves; early spring spraying of apple fruit trees before the buds swell; spraying apple fruit trees during the period of bud release, during the pink bud phase and after flowering as the disease develops; In case of severe damage to fruit trees, apple trees are treated with several fungicides every 10-15 days.