Content
- Lilac has brown spots on the leaves - causes and their elimination
- Leaflets caused by pathogens
- Pseudomonas syringae
- Ascochyta syringae
- Lilac leafminer
- Tips
The Fliederminiermotte can be responsible for brown spots
Lilac has brown spots on the leaves - causes and their elimination
Actually, the common lilac (Syringa vulgaris) is a very robust, long-lived plant that is rarely attacked by diseases of all kinds. An infection is therefore often due to a wrong and inadequate care, an inappropriate location or unfavorable weather.
Leaflets caused by pathogens
Brown spots on the leaves can be caused by various bacteria, fungi or even viruses. With the naked eye, the specific pathogen is hardly diagnosable to the layman, but a skilled gardener will be able to help you in this regard.
Pseudomonas syringae
The fungal pathogen causes a disease called "lilac" or "bacterial shoot rot". It begins at the base of young shoots, which suddenly start to assume a strip-shaped, dark brown to black color from May. Later on the stems and leaves also show irregular, dark brown spots, furthermore, the inflorescences tend to wither and wither. The disease often occurs after very frosty or wet winters, also strongly nitrogen-stressed fertilized lilacs are endangered.
How to find a remedy: Cut the affected lilac deep into the healthy wood and burn the clippings. Preventive measures should be taken to avoid frost-prone layers and highly nitrogenous fertilization.
Ascochyta syringae
This fungus causes the leaf spot disease, in which also first the young shoots wither, then turn brown and die off. The leaves are also affected, they get irregularly shaped, blackish brown spots and the edges curl up.
How to remedy this: The affected lilac must be cut deeply into the healthy wood, the clippings are to be burned or otherwise disposed of (but not on the compost!). Furthermore, treat the plant with a copper-containing preparation, which you get in the garden shop.
Lilac leafminer
The lilac moth is one of the most common pests and does not occur only on lilacs. They can also be found on ash, forsythia, Deutzia, snow berries and privet. First damage occurs in early summer, when large, irregular, brown patches become visible on the leaves. Later, the leaves cripple and dry up. If you look closely, you can detect caterpillars (with the help of a magnifying glass, for example).
How to find a remedy: After an infestation in the previous year you should already spraying neem several times in the following year when the leaves are sprouting. Further measures are not necessary.
Tips
Old lilacs of the species Syringa vulgaris as well as the wild forms are usually more robust and less prone to diseases than new varieties or hybrids.