If the medlar gets black spots on the leaves, you should get to the bottom of the cause. Both fungi and incorrect care measures can come into question. Proper prevention reduces the risk.
Fungi cause spots on the leaves of the medlar
fungal diseases
Various fungi cause diseases that are collectively grouped under the term leaf spot disease. The spots are often bordered and, in the case of severe fungal infestation, enlarge until they finally cover the entire leaf surface. If left untreated, the fungal diseases lead to the leaves drying up and dying off. It is difficult to determine which fungus is specifically responsible for the damage based on the colour.
Leaf blight is a common fungal disease that shows up on the leaves of medlar. The fungal spores prefer to settle on young leaves, but also on the foliage of weakened and diseased plants. Rain and wind favor their spread. They find ideal growth conditions in a humid environment with warm temperatures. A disease can be recognized by the spots on the leaf surfaces. The spots can appear red, brown, or black. In the case of a severe infestation, the spots spread widely on the leaves.
drought stress
Patchy discolouration can be caused by unfavorable weather conditions. Drought stress is a possible cause of sudden leaf spot that shows up in spring or summer. While the stress response in winter is caused by long-lasting ground frosts in combination with direct sunlight, longer periods of heat in summer favor the development of spots.
In both situations, a lack of water is the reason for the discoloration. In winter, the roots in the frozen ground cannot absorb water. Plants lose moisture when the winter sun shines on the leaves. This liquid deficit occurs in summer if the plants are not watered regularly.
preventive measures
Find the perfect location that offers your photinia optimal conditions for growth. An ideal spot offers protection from the direct sun and strong winds. The substrate is loose and well drained. Gloss medlars must not be too close together, otherwise the foliage will not be sufficiently aerated. As a result, a humid microclimate is created, which provides fungi with optimal living conditions.
Strengthen your plants with:
- a broth made from field horsetail
- fertilization in spring
- regular watering