Healthy magnolias are rarely attacked by fungal diseases. Fungi, especially the three mentioned in the text, penetrate trees that are weakened or injured (e.g. by unclean cutting tools). Always treat fungal diseases as soon as possible, as the pathogens weaken the magnolia and can even cause it to die.

Powdery mildew and downy mildew

If you notice a greyish or white coating on both the upper and lower side of the leaf, it is very likely that it is powdery mildew. There are two variants of this. Powdery mildew is also known as the "fair weather fungus" because it mainly appears on warm and dry days. Downy mildew, on the other hand, prefers cooler and wetter weather. Powdery mildew can be treated quite well with household remedies (e.g. garlic or nettle broth), with a heavy infestation a copper-containing fungicide helps.

Nectria cinnabarina (Cinnabar Pustule)

This fungal disease affects branches and twigs of the magnolia and is mainly introduced by unclean cutting tools. You can recognize an infestation by the orange-red or pale red spots on the branches. Nectria cinnabarina is dangerous because the fungus introduces toxins into the plant's metabolism, first weakening it and then causing it to die off. It mainly occurs when there is a lack of water or extreme heat. Cut back the affected areas generously into the healthy wood and dispose of the clippings immediately - they remain contagious for other plants as well.

Botrytis (grey mold)

Botrytis, also known as gray rot or gray mold, is particularly insidious. It attacks almost all parts of plants from the roots to the last leaf and even the fruit, feeding not only on living but also on dead material. However, the fungus preferentially attacks (if one can speak of it in the case of a fungus) the bark of young shoots as well as the leaf and flower buds. The tree appears to be covered in a gray-white carpet - which it is, since this is the very rapidly spreading mushroom carpet. Remove all affected plant parts and keep them in a tightly closed plastic bag. Then, or if the infestation is too severe, choose a sulphur-containing fungicide, for example with the active ingredient fludioxonil.

tips and tricks

Since prevention is still better than cure, only cut your magnolia with a perfectly clean pruning tool and then seal the wound with tree resin. Also, remove dead or diseased plant parts immediately to keep the plant strong.

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Trees