Powdery mildew on an apple tree: photo, description, treatment with folk remedies, preparations

Powdery mildew on an apple tree is a dangerous fungal disease that can be treated in the early stages. It manifests itself as a white coating on branches, leaves, flowers and fruits. Over time, it becomes red or brown, the fungus can affect almost the entire tree. The main methods of treatment are chemical and biological drugs. Also, for prevention and control, folk remedies are used, which can give a good result in unopened cases.

Description of powdery mildew

Powdery mildew is an infectious disease caused by microscopic fungi from the powdery mildew group of the same name (Erysiphales). The name is due to the fact that when the ground parts of the plant are affected, they become covered with a white coating resembling flour. Therefore, powdery mildew is often referred to as linen or ash.

The body of fungi is represented by a superficial mycelium (mycelium), at the ends of which hyphae grow. They turn into the so-called appressoria – flat thickenings, with the help of which the pest is attached to the surface of a leaf, stem or bud. Through them, fungi draw water and nutrients from the apple tree, which adversely affects the health of the tree and leads to a decrease in yield.

Fungi infect the apple tree with spores at temperatures from 0 to 20 degrees Celsius and relative humidity of more than 50%. The incubation period lasts for 3-11 days (usually 4-5). Further, a powdery coating appears on the surface of the apple tree. If nothing is done, the fungus will take over a significant part of the tree. During the season, it gives several generations, so it can spread to neighboring plantings.

The spores spend the winter in the buds of apple trees and other trees. At this time, they are not very active, so the symptoms are not noticeable. If the temperature drops even for a few days to -20 degrees, the pest will die. That is why most often powdery mildew is observed not in Siberia, in the Urals or in the north, but in the middle lane, the Black Earth Region and in the south of Our Country. In the spring, spores become active and begin to divide, after which a new cycle begins.

Infected apple leaves

What powdery mildew looks like on an apple tree

You can detect powdery mildew on an apple tree with the naked eye. The main symptoms are:

1. White coating on leaves, buds, ovaries, branches. It resembles a powdery coating and is easily washed by hand or rinsed off with water.
2. New shoots of irregular shape, narrow leaves, internodes noticeably shorter.
3. The plaque darkens, becomes red or brown.
4. Affected leaves and shoots lose their ability to process photosynthesis and die off, then fall off.
5. On the reverse side of the leaves of the apple tree, powdery mildew gives stains, which is why the plate curls and dries.
6. The fruits are covered with whitish spots, after which a rusty mesh appears on them. At the same time, the defeat is not only on the surface, but also goes to the depth, because of which the apples have to be thrown away.

Powdery mildew fungi are a serious danger to apple trees and fruit trees. Experienced gardeners and farmers say that on average, crop loss can be about 50%, and often up to 80%. If the disease has covered a significant part of the apple tree, it may die. To prevent the tree from infecting neighboring plantings, it is easier to cut down and burn it.

Causes of powdery mildew on apple trees

Powdery mildew is widespread almost everywhere. It affects the apple tree, fruit and berry, vegetable, ornamental and other crops. The main reasons for its development are:

1. High humidity and moderate temperature (in the range of 18-25 degrees). At 30 degrees and above, spores die en masse.
2. Excessive watering or, conversely, an acute shortage of moisture (dry, cracked soil).
3. Excess nitrogen fertilization and calcium deficiency in the soil.
4. Radical pruning for rejuvenation (more than a third of the length of the branches).
5. Unharvested leaves and other plant debris in autumn. Powdery mildew spores can also overwinter in them.
6. Thickened plantings, weak air flow (for example, an apple tree grows next to a fence, garage).
7. Pests: aphids, spider mites and whiteflies.
8. Lack of sunlight, landing in a shaded area.

The fungus is activated in April-May, when the air warms up to 10-12 degrees

How to deal with powdery mildew on an apple tree

Powdery mildew on an apple tree can be treated by various means, for example, chemical or biological preparations. The folk recipes described below also help.

Folk remedies for powdery mildew on an apple tree

Processing apple trees from powdery mildew with folk remedies is quite effective in the early stages. They can also be used for prevention and during the fruiting period, when the use of chemicals is undesirable. Among the most effective recipes are the following (the amount is given for a standard bucket of water with a volume of 10 liters):

1. Potassium permanganate – 5 g.
2. Whey or milk of any fat content – 1 l.
3. Infusion of wood ash – 1 kg per 10 liters of hot water. Infuse for a day and add a little liquid soap or shavings of laundry soap (50 g).
4. Fresh manure – 3 kg. Infuse for three days in cold water (10 l), then filter through a dense cloth and dilute 10 times.
5. In summer, you can fight powdery mildew on an apple tree with an infusion of any weeds – 5 kg per 10 liters of boiling water. Insist 3-4 days, filter and proceed to processing.

Powdery mildew fungicides on apple trees

Spraying apple trees from powdery mildew with chemicals is necessary in a number of cases:

• at the stage of prevention in early spring;
• before the fruiting stage;
• if the disease is running, and folk remedies do not help.

For the treatment of apple trees, you can use different drugs. The most effective fungicides for powdery mildew are:

• “Score”;
• “Tsideli Top”;
• “Topaz”;
• Fundazol;
• “Abika Peak”;
• “RAW”.

“Skor” – a proven fungicide against powdery mildew

The treatment is best combined with insecticides, since many insects are carriers of spores and also weaken the tree. Spraying is carried out totally on all leaves, branches and flowers. Moreover, it is better to do this in the late evening, in dry and calm weather.

Biological preparations for powdery mildew on an apple tree

It is better to treat a flowering apple tree from powdery mildew with biological preparations. They are also used for treatment at the fruiting stage. Many chemicals have long waiting times of 10 to 30 days. This is the time that must elapse from the last treatment to harvest. Biological agents have shorter terms – 3-7 days.

For quick treatment of the disease, the following drugs are used:

• “Fitosporin”;
• “Trichodermin”;
• “Baktofit”;
• “Gamair”;
• “Alirin-B”;
• “Sporobacterin”.

How to protect an apple tree from powdery mildew

The main way to prevent the disease is to follow the rules of planting and care. Experienced gardeners recommend paying attention to the following tips:

1. Plant trees in open, sunny areas with a minimum spacing of 4 meters (even if the crown is not very spreading).
2. Avoid lowlands and closed places near buildings where air circulation is poorer.
3. Observe the watering rate, avoiding excessive waterlogging and cracking, drying out of the soil. Adult trees (from 3 years old) are given at least five buckets of water, young trees – two.
4. Regularly apply fertilizers, including phosphorus-potassium. Such top dressing is especially important during an outbreak of infection.
5. Do a thinning pruning every year. Remove all leaves and branches in the fall and burn them, taking them away from the site.
6. Before pruning, be sure to disinfect the blades of the tools in a weak solution of potassium permanganate or fungicide.
7. Remove weeds as needed – they also contribute to the spread of spores.
8. For prevention, you can dust the apple tree and the trunk circle with wood ash.

Disease resistant apple varieties

Breeders have developed quite a few varieties of apple trees that are resistant to various diseases, including powdery mildew: Amulet, Red Poppy, Red Amber, Agro, Redfree, Rodnichok, Soyuz, Palette, Fairy, Prestige, Fortune, Orion, Talisman, Linda and others .

“Talisman” is one of many varieties resistant to the disease

When choosing a crop, you should pay attention to other features, for example, winter hardiness. It is very important to purchase those seedlings that are well adapted to the climatic conditions of a particular region.

Conclusion

Powdery mildew on an apple tree is quite dangerous, it can hit several trees at once. The pest develops especially actively in cloudy weather. Plantings should be periodically inspected, and when the first signs appear, it is imperative to treat with fungicides. If you follow the basic preventive measures (watering, fertilizing, pruning, spraying with drugs), the trees will remain healthy.