If the yucca suddenly gets a lot of round, brown to blackish spots on the leaves, then there is usually a fungal infection behind it. This can have a number of causes, most likely you have kept the plant too moist. Outdoor yuccas often get these spots after a wet winter.
Brown spots on the leaves usually indicate a fungal infection
Leaf spot occurs due to fungal infection
The leaf spots appear sporadically at first, but gradually affect more and more leaves (whereby new shoots are initially spared) and gradually enlarge. Sometimes they can spread over the entire leaf, turning some or all of it brown and drying up. The damage is caused by various fungi, which are mostly spread by water droplets on the leaves (e.g. due to improper watering or rain) and by drafts.
Treat infested yucca properly
The best way to treat infested yuccas is as follows:
- Separate the affected plant to prevent further spread.
- However, this is not always possible, especially with planted specimens.
- Cut off all affected leaves close to the stem.
- Treat the affected yucca with an antifungal agent.
- You should first resort to home remedies, for example infusions of tansy, horsetail or stinging nettle.
- However, these remedies only help in the early stages of the infestation.
- If this is already more advanced, only chemistry can help.
- You can treat the fungus with fungicides containing sulfur or copper (e.g. net sulfur).
- or use a broad spectrum fungicide. This is necessary because the exact type of fungus cannot usually be determined.
Be careful not to spray the yucca with fungicides indoors. For this purpose, always place the plant outside, for example on the balcony or in the garden!
Prevent fungal infestation
Fungi are among the so-called weak parasites that almost exclusively attack plants that have been weakened by care errors. You can recognize a fungicidal infestation not only from leaf spots and pustules, but also from coatings or coatings on leaves and shoots and from partial wilting. These care mistakes are usually the causes of a fungal infection:
- Improper water supply (in most cases too much)
- too much or too little fertilizer
- too high / too low temperatures
- 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.
tips
Sometimes brown leaf spots are caused not only by fungi, but by pests. Check the affected plant closely for animal pests.