Apple orchard is undesirable to ignore. One year the summer turned out to be wet, with fogs. In just a few days, three out of seven apple trees suddenly fell ill. At first they covered with white dust, then the leaves began to curl and brown. The apple tree began to discard the ripened fruits. The crop failure turned out to be commonplace: powdery mildew.
What fungus infects an apple tree
Powdery mushrooms often affect melons, berry bushes: gooseberries, currants, acacia, hawthorn. The fungi Erysiphales, Phyllactinia guttata of the Erysiphaceae family of the Ascomycetes class (Ascomycetes) inhabit only apple trees. This type of mushroom does not affect other crops. 
Candidate Education
The development cycle of a fungal infection of apple trees is divided into two stages:
- Formation of candida (germinated spores), they die only at -20 ° C. Manifested in spring with white spots. If they are viewed under a magnifying glass, mycelia - the cobwebs of the fungus - will be visible. Flour-like plaque - ripened spores of the mycelium.
- Marsupial, begins 30 days after the lesion. Black fruiting bodies with branched appendages appear (dark dots on the leaves).
Powdery mildew is a harmful pest. Spores are carried by wind, birds, with tools, on clothes. The pathogen inhibits plant growth, inhibits photosynthesis.
Foliage curls, dries. Affected buds, inflorescences. Crop is reduced to 80%, winter hardiness of the tree is deteriorating, part of the crown has to be cut.
Manifestations and means of struggle
First, a lesion manifests itself in white plaque, similar to building dust. Formed at the very tips of the branches:
- young leaflets;
- kidneys;
- flower petals;
- bark of twigs.
Frankly, I did not immediately pay attention to the powdered shoots. I thought the first rain would wash away the raid. There it was! The whitish hue gave way to yellowness, a black spot appeared.
The leaves began to dry, autumn came for the trees - it was time for leaf fall.
How to deal with powdery mildew on an apple tree
It is difficult to get rid of candida; they winter well. I noticed that the field of processing trees on a green cone (when the buds are just starting to blossom) does not show signs of plaque. What to process - I will say separately. I always carefully inspect the garden when persistent fogs appear in the morning. For the development of apple mushrooms, comfortable conditions are high humidity and heat (as, however, for all other types of powdery mildew). In order for the crown to be well ventilated, regular sanitary pruning is needed. The clinging mycelia will slow growth, if moisture is not enough, it will melt until better times.
Processing time:
- the first is done in early spring, you can use powerful fungicides;
- secondary after two weeks with the same drugs;
- preventive is necessary when favorable conditions arise, it is better to use biological products that are harmless to insects;
- the final autumn is needed after harvesting, not only the crowns are sprayed, but also the fallen leaves, soil.
It is noted that the plant is less likely to get sick if it has enough phosphorus, calcium, potassium. With an excess of nitrogen, on the contrary, the leaves grow loose, the mycelia catch more easily.
Powdery Mildew Treatments
Let's look at several drugs with different effects:
Fungicides (chemicals, not safe, but effective):
- Topaz;
- Impact;
- Flint Star;
- Chorus;
- Tersel;
- Privent;
- Rubigand;
- Cumulus DF;
- Tiowit Jet.
Diluted according to the instructions. The maximum processing ratio is 3 times with an interval of 2 weeks.
Do not forget about personal protective equipment: gloves, a bathrobe, a hat, glasses, a protective mask that covers the mouth and nose.
Well suited for processing colloidal sulfur. She is bred at the rate of 20 g per 10 liters of water. The substance is safe for animals, insects. With severe damage, the interval between treatments is reduced to a week. Sulfur is effective at temperatures from +18 ° C to +20 ° C. In extreme heat it can cause burns on the leaves.
Two more popular tools:
- Phytosporin is a safe biological product that is active against many fungal diseases.
- Bordeaux fluid is often used for spring and autumn preventive treatment.
Folk remedies:
- onion husk infusion (the higher the concentration, the better);
- weakly violet manganese solution is ineffective in severe lesions;
- whey solution (dilute a liter package in 5 liters of water).
Powdery mildew resistant apple varieties
Hybrids genetically protected from powdery mildew, scientists have not yet been able to bring. But it has been noticed that there are varieties on which powdery mildew appears extremely rarely. There are many of them, they adapt well in mid-latitude conditions:
- Amulet (medium-sized red);
- Gloucester (red-green, elongated, tapering to the tip);
- Mutsu (bell-shaped, yellowish);
- Ligol (red, elongated);
- Florina (red-green, sweet).
Just in case, I will list others: Red Amber, Summer Golden (early ripening), Orion, Talida, Carmen, Talisman. Red Poppy, Argo, Prestige.
When buying a seedling, it is better to choose zoned varieties, they are based on well-wintered scab-resistant apple trees. It is noted that varieties that are not prone to scab are much less likely to be covered with powdery mildew.
Have a good harvest! Remember, the main thing is not to thicken the crown, in time to feed the apple trees with potassium, calcium, phosphorus, especially with the contrast of night and day temperatures. Preventive treatment will also never hurt.
