Glossy medlars are extremely robust and are rarely affected by diseases. Weakened plants have a higher risk of infection with various diseases that can be fought with simple means.
Leaf tanning is relatively common in the medlar
These diseases can occur:
- leaf tan
- apple scab
- mildew
- fire blight
leaf tan
This disease is caused by a fungus whose spores spread with the wind. The fungus prefers to grow in damp and rainy weather. If a plant is diseased, it gets patchy discoloration on its leaves. An environment with high humidity promotes the spread of the pathogen. Shrubs that are too dense are not sufficiently ventilated, so the fungus prefers to spread in compact hedges. Infection of other plants is possible through affected fall foliage.
Make sure there is sufficient planting distance. Photinia should be watered at the base of the stem so the leaves don't get wet. Strengthening the shrubs with nettle decoction makes them more resilient. Weakened individuals are more likely to be colonized by the fungal spores. You can combat leaf tan by spraying the infected leaves with a copper sulfate remedy.
apple scab
In months with high rainfall there is a risk that medlar will be attacked by apple scab. This fungal disease manifests itself as greenish spots. With a heavy infestation, the spots widen, which leads to the death of cell tissue in the leaf. Rain promotes the spread of the disease. The fungi are spread by a special form of spores that are formed asexually.
It is important to act quickly because the fungus spreads quickly in warm temperatures combined with high humidity. Affected leaves should be removed and burned to prevent the fungus from spreading further. Disposal with household waste is also possible. Then spray the wood with a triforin-based fungicide.
mildew
Downy mildew also loves damp conditions. This fungus occasionally affects weakened medlars in the rainy summer months. The disease can be recognized by a white coating that appears both on the upper side and on the underside of the leaf. If the infestation is severe, there is a risk that the affected leaves will die off
Powdery mildew depends on high humidity. As soon as the air becomes drier, the fungus cannot spread any further. Remove infected leaves and give the plant a decoction of horsetail to support its vitality. To prevent disease, you should ensure sufficient spacing when planting.
fire blight
Dried flowers and leaves or black discoloration indicate fire blight. This disease is caused by a bacterium that gets into the plant organism through injured areas on the branches or through the flower. The disease is mainly spread in Switzerland. Plant shipments allow infected plants to spread the bacterium.
This disease is notifiable even if there is only a suspicion of infection. So far there are no treatment measures. Since it spreads quickly, you should act quickly at the first sign.