In recent years, apple trees whose bark has turned unnaturally dark have become increasingly common. Because of its appearance, the disease responsible for this phenomenon is called black bark burn. We show you how you can prevent and combat it.
What is black bark burn on apple trees?
Black bark blight is a tree diseasecaused by fungiof the genus Diplodia,which affects the vitality of the tree. A black coloring of the bark is typical. The bark tears open and separates from the wood.
What does black bark burn look like on apples?
Initially there are flat, sunken,dark bark necrosismainly on the trunk and the leading branches. As the disease progresses,tearing thickenings develop on the bark and the bark separates from the wood.
Large, dark discoloration occurs, which makes the apple tree appear burned. Black rot is visible in the cross section due to cellulose degradation. This damage often occurs on the side of the trunk that faces the sun. There are almost always frost cracks or other injuries in the immediate vicinity.
What can you do if bark burn is in the early stages?
If the infestation is not yet too severe, theaffected area should be generously cut out:
- Wear disposable gloves when carrying out this work.
- To thoroughly remove the fungus, use a very sharp knife and a cordless screwdriver with milling heads.
- Carefully disinfect the cutting tool before and after.
- Make sure that the peeled plant parts fall onto a surface and dispose of them with household waste.
- Close the wound with a fungicide-containing wound closure paste (€17.00 on Amazon).
Can a severe infestation with bark burn be cured?
If the black bark burn covers theentireshoot ortrunk, it will inevitablydie. That's why black bark blight is often a death sentence, especially for young apple trees.
- For older fruit trees, you should cut back the dead branches right down to the he althy wood.
- If the apple tree's vitality is already severely limited, it must be felled.
- To prevent the spores from spreading, burn the clippings as soon as possible or dispose of them in accordance with local regulations.
Can you prevent bark burn on apple trees by watering?
To prevent bark burn, you should water theapple treeregularly during long dry periodsIn this way you prevent the trees from becoming thirsty During periods of heavy rain, you suddenly absorb a lot of water. This means that no tension can occur in the conductive pathways, which could lead to cracks in the bark.
It has proven to be a good idea to provide paint pots with small holes and place them in the area of the root system. As a result, the water seeps into the ground drop by drop and supplies the apple tree evenly with liquid.
How can I prevent bark burn on apples?
There areother measuresthat can help preventbark burnfrom occurring in the first place:
- Experts recommend painting the fruit tree white. The decreasing temperature differences prevent frost cracks.
- Keep the tree disc free of vegetation and mulch it. This leads to less competition for water and the moisture is better retained in the soil.
- To increase resistance, you should strengthen the apple tree with appropriate nutrient supply.
Tip
Do not fertilize from July onwards
If you supply the fruit tree with nutrients in summer, young shoots will form that will not fully mature until winter, will freeze and weaken the tree. To ensure good shoot completion, the last fertilization should take place at the end of June.
