If the yucca suddenly gets lots of round, brown to blackish spots on the leaves, then there is usually a fungal infection behind it. This can have various causes, most likely you kept the plant too moist. Outdoor yuccas often get these spots after a wet winter.
What causes brown spots on Yucca palms?
Brown spots on yucca palms are usually caused by fungal infections caused by improper watering, drafts or damp weather. Affected leaves should be removed and the plant treated with a suitable fungal agent. As a preventive measure, optimal care and a balanced room climate are important.
Leaf spots occur due to fungal infection
The leaf spots initially appear sporadically, but gradually affect more and more leaves (although new shoots are initially spared) and gradually enlarge. Sometimes they can spread over the entire leaf, causing all or part of it to turn brown and dry out. The damage is caused by various fungi, which are usually spread by water droplets on the leaves (for example through improper watering or through rain) and through drafts.
Treat infected yucca properly
Infected yuccas are best treated as follows:
- Separate the infected plant to prevent further spread.
- However, this is not always possible, especially with planted specimens.
- Cut off all affected leaves directly on the trunk.
- Treat the affected yucca with an antifungal agent.
- You should first resort to home remedies, for example infusions made from tansy, horsetail or nettle.
- However, these remedies only help in the initial stages of the infestation.
- If this is further advanced, only chemistry can help.
- You can treat the fungus with fungicides containing sulfur or copper (e.g. net sulfur (€6.00 on Amazon))
- or use a broad-spectrum fungicide. This is necessary because the exact type of fungus usually cannot be determined.
Be careful not to spray the yucca with fungicides inside the home. For this purpose, always place the plant outside, for example on the balcony or in the garden!
Preventing fungal infestation
Fungi are among the so-called weakness parasites that almost exclusively attack plants that have been weakened due to care errors. You can recognize a fungicidal infestation not only by leaf spots and pustules, but also by deposits or coatings on leaves and shoots and by partial wilting. These care errors are usually the causes of a fungal infection:
- Incorrect water supply (too much in most cases)
- too much or too little fertilizer
- temperatures too high / too low
- Lack of light
- dry heating air
In order for the treatment of the fungal disease to be successful, you must eliminate the cause(s). Otherwise the fungus will spread again.
Tip
Sometimes brown leaf spots are caused by pests rather than just fungi. Check the affected plant closely for animal pests.
