You have probably seen this type of damage many times: thick growths can be found primarily on apple trees, but also on other fruit and deciduous trees. Over time, these even increase in size and cause the branches and twigs above them to die due to the lack of supply. However, there are preventative measures that can be taken to avoid an infestation.
How can you prevent and combat fruit tree cancer?
Fruit tree cancer can be avoided through good choice of location, balanced fertilization and proper wound care. Affected branches should be cut off below the cancer site and wounds should be treated with wound closure agent to ward off fungal pathogens.
Cause and damage
The cause of fruit tree cancer is not cells growing uncontrollably like in humans, but a fungus. As a result, despite having the same name, the fruit tree disease has nothing to do with the human disease. If this disease occurs, growths appear on the trunk or branches that continue to expand. The branch or twig above the cancer sites itself dies because the water and nutrient supply is interrupted. In winter, spherical red mushroom fruits are produced containing the spores of the fungal pathogen. They enter the tree through wounds; These can be cuts, but also wounds caused by hail, frost or deer.
Prevention
For this reason, larger cuts, such as those caused when pruning fruit trees, should be applied with a wound closure agent such as Malusan (€73.00 at Amazon) or similar. As a preventative measure, fruit trees should only be planted in locations that suit them cold locations and moist, heavy soil promote its occurrence. One-sided or very nitrogen-based fertilization also has a cancer-promoting effect, which is why fruit tree cancer is often found in farm gardens fertilized with manure. Certain apple varieties are considered to be very susceptible, this applies in particular to 'Berlepsch', 'Cox Orange', 'Gloster', 'James Grieve', 'Klarapfel' and 'Oldenburg'.
Combat
Twigs and branches infected with fruit tree cancer should be cut off a hand's breadth below the cancerous area. On the other hand, cancerous areas on the trunk and on thicker branches are cut out into the he althy wood using a knife or, if necessary, a saw. Final treatment with a wound closure agent is absolutely necessary to prevent the pathogen from re-invading. In commercial fruit growing, agents containing copper are used to combat it, but these are not approved for use in home gardens. As a heavy metal, copper accumulates in the soil and affects the organisms living there.
Proper wound care on fruit trees
Damage caused to fruit trees by tree cancer (as well as by frost, pest and wild animal damage, branch monilia or fruit tree pruning) should definitely be treated so that they heal quickly and the penetration of fungi and other pathogens is prevented. For larger cancer areas, proceed as described:
- First cut out the cancer areas deeply with a saw.
- Very deep areas of infestation are then reworked with a chisel.
- At least a third of the branch circumference must be left for supply.
- For rapid healing, the edges of the wound are smoothed with a sharp knife.
- Apply a wound closure agent to large wounds.
Tip
Winter frost damage can be avoided if you apply a coat of lime to the fruit tree.
