No apple tree, no matter how well cared for, is completely immune to disease. And in fact, a whole host of pathogens are known to target its bark, leaves or the fruits reserved for us. When the damage shows up, there is no place for resignation. The tree needs our help. But which apple disease do the visible traces point to?

1. Apple powdery mildew

At first this fungal pathogen appears on only a few shoots, but soon one leaf after the other is conquered at breakneck speed. The numerous insects floating around in a garden, as well as wind and rain, help him.

  • young shoot tips are coated with “light powder”
  • Leaves roll up and dry up

If you are planning to plant a new apple tree in the garden, it is best to choose a non-susceptible variety. You can fight an infection that has already occurred with the following measures, among others:

  • Radical cut of the diseased shoots into healthy wood
  • Use of biological sprays
  • z. B. Fresh milk and water in a ratio of 1: 8
  • spray every few days
Note:  You should also ensure that your apple tree has an airy crown through regular pruning. This allows the leaves to dry off quickly after rain. Most mushrooms love a moist environment.

2. Apple mosaic virus

The apple mosaic virus is one of the rarer apple tree diseases, which luckily does not pose a threat to other trees in the garden. It is assumed that the infection is caused by sick refining material. You can recognize apple mosaic virus by these signs:

  • white and yellow spots on the leaves form a mosaic pattern
  • the disease shows itself only in a few instincts
  • Finally, all sheets are marked with patterns

The unsightly appearance is followed by crop losses and weak shoot formation. Unfortunately, you cannot fight this virus. However, so that it does not spread further, no leaflets should be used from the diseased tree.

3. Apple scab

The apple scab can cause considerable damage to the apple tree. That is why it is important that you recognize and combat the symptoms in good time, which it sends on the leaves before the fruits form.

  • Leaves are brown in color
  • bumps form in the leaf structure
  • Leaves dry up and fall off in large quantities
  • the fruits also turn brown in places and show cracks

With some apple varieties, you can fight apple scab well with sulfur sprays. Other varieties, on the other hand, immediately call for a fungicide. In addition, the following measures should be taken:

  • Cut diseased tree parts into healthy wood
  • Collect and dispose of fallen leaves
  • otherwise the fungus hibernates in it and strikes again in the following year
  • Strengthen resistance with horsetail broth
  • keep the crown airy with regular pruning measures

4. Fire blight

The fire blight caused by bacteria is one of the most dangerous apple tree diseases for two reasons:

  • Fire blight leads to the death of the affected tree
  • this disease quickly spreads to neighboring trees

Due to the danger to other trees, any suspected fire blight must be reported to the responsible office. Failure to do this risks substantial penalties. In coordination with the office, a decision will then be made on further measures. Most of the time the tree is cleared and burned. Only very rarely can a tree be saved in the early stages by very strong pruning measures. The symptoms of the fire blight stand out clearly from other damage images so that you can easily recognize it:

  • young shoots and flowers turn brown to black
  • but they stay attached to the tree
  • the whole tree looks burned as a result
Idea:  Since there is no effective remedy for fire blight, the only way to keep it away from your own apple tree is to use a resistant variety when planting.

5. Glassiness

Glassiness is a metabolic disease in which the apple produces too much sugar. The effects are only visible on the fruits:

  • inside the apple is watery and glassy
  • usually around the core casing
  • Glassiness can decrease with storage

A calcium deficiency is suspected to be the cause of this disease. Other favorable factors are said to be too much sunlight and too dense a crown. For the following season, you can therefore pay attention to calcium-based fertilization and align branches that are too close together.

6. Kelchfäule

There is a lot of time between the infection in spring and the first visible symptoms in autumn during which the disease remains undetected.

  • Fruits get brown spots in the calyx area
  • these dry out in the further course and sink in
  • invisible inside, the core casing is also rotten
  • After a long period of storage, the pulp will also rot

If you discover apples marked in this way on your apple tree, any help for the current harvest will come too late. The diseased fruits must of course be picked up promptly so that the pathogen disappears from the garden. Only if the tree suffers from the disease repeatedly should the use of a fungicide be considered.

7. Collar rot

This fungal pathogen is already in the garden soil, what has to be added is plenty of moisture. Then the infection can occur more easily. While the symptoms of other apple tree diseases show up soon after infection, it can take several years for collar rot to be noticed externally.

  • there are small rotten spots on the bark
  • these expand over time
  • The bark turns purple and sinks in places
  • the wood is not attacked

Once a disease has broken out, it can no longer be stopped. However, prevention is quite possible:

  • choose resistant varieties
  • Avoid waterlogging
  • loosen heavy soils and make them more permeable
  • Prevent injuries to the bark

8. Monilia fruit rot

Codling moth and apple saw wasps usually go ahead and pierce the fruit, the monilia mushroom follows through the open hole. In damp weather, the spread of Monilia fruit rot can hardly be stopped.

  • Fruits are getting brownish and brown
  • there are also white spots of mold on the shell
  • More and more so-called fruit mummies are hanging on the tree

The damaged fruits are no longer suitable for consumption. However, they must not remain on the ground either, as they carry the fungal pathogen.

They should be disposed of as soon as possible.

Note:  Don’t forget to fight codling moths and apple saw wasps, as they are directly involved in the spread of apple disease.

9. Monilia peak drought

During the peak drought, the monilia fungus attacks the leaves and blossoms of the apple trees.

  • Leaves wither and dry up
  • mostly only shoot tips are affected

You can combat peak drought by cutting back the diseased branches generously into the healthy wood. As a preventive measure, an organic plant tonic can be sprayed after the first shoot. Aligning the crown also slows down the spread.

10. Fruit tree cancer

Fruit tree cancer is not cancer in the conventional sense, because it belongs to the apple tree diseases that are caused by fungal pathogens. What led to this name are the strong growths that the apple tree develops on the trunk and branches during the course of the disease. Other signs that you can use to recognize fruit tree cancer include:

  • dry and cracked bark
  • orange-brown discoloration in places
  • sometimes individual branches die off
  • round, red spore beds are visible

You cannot finally fight fruit tree cancer, but it does help to cut away the strong growths on the trunk and to seal the wounds with tree wax. Dead branches are also removed. Although this disease ultimately ends with the death of the apple tree, many more fruitful years can pass before then.

11. Soot spot disease

Preventive spraying against soot stain is mandatory in commercial buildings. In private gardens, on the other hand, it is one of the most common apple tree diseases.

  • Fruit peels get greenish-black spots
  • in the case of severe infestation also completely with a black coating
  • after rubbing, the stains recede somewhat

Anyone who splashes against apple scab will also get the soot stain under control. As a preventive measure, rapid drying must be ensured through regular pruning, as moisture and raindrops transport the fungal pathogen.

12. Stippiness

In addition to vitreousness, stippling is the second common metabolic disease due to calcium deficiency. However, this is less of a nutrient problem in the soil than a transport problem in the apple tree. Affected apple trees do not show any signs of damage at the beginning of the vegetation period, by which the disease can be recognized. Only the fruits provide clear clues:

  • there are brown spots in the flesh,
  • often only appear during storage
  • the apple tastes good at the beginning
  • later becomes bitter and inedible

If there is fear of speckling, a 0.5% calcium chloride solution can be sprayed directly onto the fruit from July. The leaves themselves mostly show no calcium deficiency. The ratio of leaves to fruits should also be balanced, which requires occasional thinning.

13. Root goiter

If the roots of an apple tree are injured during planting or later digging, the bacteria that cause the root goiter can introduce through the open areas. The flow of sap is inhibited, which results in stunted growth and a correspondingly smaller harvest. The symptoms of the disease are located below the surface of the earth and are therefore only perceived after specific exposure.

  • Roots are covered with tumors
  • these can reach the size of tennis balls

If the infestation is very severe, the tree can die soon. As a preventive measure, be careful not to damage the roots of the trees. This bacterium survives in the soil for a long time and can attack newly planted trees even years later.

Numerous pathogens can weaken an apple tree in this country, some of them even rob it of life. Unfavorable weather and care mistakes make it easy for apple tree diseases to spread. The soon visible damage speaks a clear language and requires an immediate and appropriate reaction. However, if you love your tree, you also take precautions.

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