Older apple trees in particular sometimes show thick growths on the trunk and perennial branches, some of which are covered by the bark. This is unfortunately a very widespread disease that can massively affect the vitality of the tree.
What are these growths on the trunk of the apple tree?
These growths arefruit tree canker,a plant disease caused by thepustule fungusNeonectria ditissima. This damages the bark and wood. When the tree tries to close the infection sites, the typical knotty swellings form.
How does tree cancer develop?
Thefungusthat causes tree cancer requires ainjury to the bark,in order toinvade the apple tree. These can be mechanical interventions such as those caused by tree pruning, but also damage caused by insects, hail or frost cracks.
Symptoms appear in the form of small, pale, sunken spots on the surface of the bark just two to three weeks after the initial infection. These dry out and turn dark. As the fungal disease progresses, the bark splits open. The following year you can discover the red fruiting bodies here.
Why do the characteristic growths form on the trunk?
Thetree tries totheinjuries caused by the fungal infectionwith bark tissue. However, the fungus is not eliminated and can continue to spread.
There is a reduced supply of water and nutrients. The apple tree is stunted in some places and only produces small fruits. In addition, calyx or storage rot often occurs.
How can you prevent growths on the trunk?
Particularlyimportantis theprofessional executionof thepruning,since the wound sites are an open entry gate represent the mushroom:
- Always prune the apple tree in dry weather. This almost completely prevents the spores from spreading.
- Try to avoid all mechanical injuries. These often occur due to incorrect attachment of tree posts, crossing branches or by hitting them with a lawnmower, for example.
- Protect the apple from frost cracks by painting it white.
How can fruit tree cancer be combated?
Check the apple tree regularly so that you can detect aninfectionwith Neonectria ditissimaearly.
- The fungus cannot be killed by approved spraying.
- Therefore, cut back smaller areas of infection and affected branches deep into the he althy wood.
- Wounds on the trunk can be cut out or milled.
- Dispose of all clippings with household waste.
The same applies to control: Carry out these care measures in dry weather.
Tip
Cutting tools should always be very clean
Tools that still have traces of other plants on them promote the spread of diseases. Therefore, wash off any coarse dirt thoroughly and then disinfect the garden tools with alcohol or vinegar essence.