Powdery mildew on an apple tree: control measures in spring, autumn, photos, what to do, causes, treatment

Content

1 Description of powdery mildew
2 What does powdery mildew look like on an apple tree?
3 Causes of powdery mildew on apple trees
4 How to deal with powdery mildew on an apple tree
5 How to protect an apple tree from powdery mildew
6 Apple tree varieties resistant to disease
7 Conclusion

Powdery mildew on apple trees 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 turns red or brown, and 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 good results in untreated cases.

Description of powdery mildew

Powdery mildew is an infectious disease caused by microscopic fungi from the group of the same name, powdery mildew (Erysiphales). The name is due to the fact that when affected, the above-ground parts of the plant become covered with a white coating, reminiscent of flour. Therefore, powdery mildew is often called laundry or ashtray.

The body of fungi is represented by surface mycelium (mycelium), at the ends of which hyphae grow.They turn into so-called appressoria - flat thickenings, with the help of which the pest attaches to the surface of a leaf, stem or bud. Through them, fungi draw water and nutrients from the apple tree, which has a bad effect on 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 a 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 produces several generations, so it can spread to neighboring plantings.

The spores spend the winter period 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 to -20 degrees even for a few days, the pest will die. That is why powdery mildew is most often observed not in Siberia, the Urals or the north, but in the middle zone, the Black Earth Region and the south of Russia. In spring, the spores become active and begin to divide, after which a new cycle begins.

Apple tree leaves affected by infection

What does powdery mildew look like on an apple tree?

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

White coating on leaves, buds, ovaries, branches. It resembles a powdery coating and is easily washed by hand or washed off with water.
New shoots are irregular in shape, the leaves are narrow, the internodes are noticeably shorter.
The plaque darkens and becomes red or brown.
Affected leaves and shoots lose their ability to photosynthesize and die, then fall off.
Powdery mildew causes spots on the back of apple tree leaves, causing the leaf to curl and dry out.
The fruits become covered with whitish spots, after which a rust-colored mesh appears on them. In this case, the damage is not only on the surface, but also goes deep, which is why the apples have to be thrown away.

Powdery mildew fungi pose a serious danger to apple 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 affected a significant part of the apple tree, it may die. To prevent the tree from infecting neighboring plantings, it is easier to cut it down and burn it.

Important! When powdery mildew is white, it is easy to deal with - you can wipe it off with your hand and treat it with drugs or folk remedies. Once it has changed color to reddish and brown, it is more difficult to cure the apple tree. In this case, it is better to use the most powerful fungicides - chemical or biological preparations.

Causes of powdery mildew on apple trees

Powdery mildew is widespread almost everywhere. It affects apple trees, fruits and berries, vegetables, ornamental and other crops. The main reasons for its development are:

High humidity and moderate temperature (in the range of 18-25 degrees). At 30 degrees and above, spores die en masse.
Excessive watering or, conversely, acute moisture deficiency (dry, cracked soil).
Excess nitrogen fertilizing and calcium deficiency in the soil.
Radical pruning for rejuvenation (more than a third of the length of the branches).
Uncollected leaves and other plant debris in the fall. Powdery mildew spores can also overwinter in them.
Dense plantings, poor air flow (for example, an apple tree grows next to a fence or garage).
Pests: aphids, spider mites and whiteflies.
Lack of sunlight, planting in a shaded area.

The fungus becomes active 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 different means, for example, chemical or biological preparations. The folk recipes described below also help.

Folk remedies for powdery mildew on apple trees

Treating apple trees against 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 10-liter bucket of water):

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

Fungicides for powdery mildew on apple trees

It is necessary to spray apple trees against powdery mildew with chemicals in a number of cases:

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

To treat apple trees, you can use different drugs. The most effective fungicides against powdery mildew are:

"Skor";
"Tsideli Top";
"Topaz";
"Fundazol";
"Abika Peak";
"HOME."

Attention! One of the effective drugs against powdery mildew on apple trees is Bordeaux mixture.

"Skor" is a proven fungicide against powdery mildew

It is better to combine the treatment with insecticides, since many insects carry spores and also weaken the tree. Spraying is carried out completely over all leaves, branches and flowers. Moreover, it is better to do this late in the evening, in dry and windless weather.

Important! Along with spraying, it is recommended to water the soil with the solution - 10 liters per tree. This will help destroy fungal spores, which is especially important in the fall.

Biological preparations for powdery mildew on apple trees

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

To quickly treat 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:

Plant trees in open, sunny areas with a minimum interval of 4 meters (even if the crown is not very spreading).
Avoid low-lying areas and closed areas near buildings where air circulation is poor.
Maintain proper watering rates, avoiding excessive waterlogging, cracking, and drying out of the soil. Mature trees (from 3 years old) are given at least five buckets of water, young trees - two.
Regularly apply fertilizers, including phosphorus-potassium fertilizers. Such feeding is especially important during an outbreak of infection.
Do thinning pruning every year. Remove all leaves and branches in the fall and burn them, taking them away from the site.
Before starting pruning, be sure to disinfect the blades of the tools in a weak solution of potassium permanganate or fungicide.
Remove weeds as necessary - they also contribute to the spread of spores.
For prevention, you can dust the apple tree and the tree trunk with wood ash.

Apple tree varieties resistant to disease

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, Palitra, Fairy, Prestige, Fortuna, 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 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 affect several trees at once. The pest develops especially actively in cloudy weather. Plantings need to be periodically inspected, and when the first signs appear, be sure to treat them with fungicides. If you follow basic preventive measures (watering, fertilizing, pruning, spraying with drugs), the trees will remain healthy.