- Determination of apple scab on the damage pattern
- prevention and countermeasures
- The long-term fight against the problem
- tips and tricks
Brown leaves amidst the green crown of an apple tree can sometimes just be a sign of a broken branch. However, they are often the first harbingers of an infection with apple scab, which is one of the serious apple diseases.
Determination of apple scab on the damage pattern
In order to delimit the problem and to determine possible countermeasures, the apple scab must first be clearly identified as such. Since apple scab overwinters as a fungal network on the leaves, it can initially be recognized as a blotchy brown coloring of the leaves. The spots are still rather small directly after budding, but then quickly enlarge. The apples also show jagged, dark spots with cracks in the middle. If the disease appears just before harvest, the fruit may shrink and become stained in storage.
prevention and countermeasures
If a first infestation with apple scab has been detected, it is usually not easy to get it completely out of your own garden. A chemical treatment usually makes little sense in private gardens, as this would have to be carried out very specifically by a biologist. However, various preventive measures can contain the damage and the spread. Tree crowns should always be cut light and permeable, as the fungus is deprived of the vital moisture on the leaves.
The long-term fight against the problem
Frequent pruning of the apple tree not only increases the dryness on the leaves, but usually also the vitality of the apple tree. which can defend itself better against the fungal infestation. In the case of old apple trees, it should also be considered whether they should generally be exchanged for scab-resistant varieties. These varieties include, for example:
- Kaiser Willhelm
- Jacob Fisher
- boskoop
- ontario
- Rewena
- Florina
It may also make sense if you give the trunk of your apple tree a new and scab-resistant crown by grafting branches of these varieties.
tips and tricks
If your garden is surrounded by hedges, you should also plant hardy apple varieties as semi-stems or standard trees. The treetops are above the lee of the hedge and can dry better after rainy seasons.