Content
- Dogwood - Common diseases and how to treat them
- Anthracnose usually causes death
- Prevent leaf tan
- Powdery mildew can be treated well
- Eliminate lice with rapeseed oil
- Tips
Brown leaves or spots on the leaves are often an indication of deficiency or disease
Dogwood - Common diseases and how to treat them
Dogwood (Cornus), also known as hornbeam, are shrubs or small trees with foliage that is often not only colorful in autumn, but also colored bark. The approximately 55 known species occur mainly in the temperate climates of the entire northern hemisphere and are considered very robust. Diseases and pests occur in dogwood only very rarely and often only as a result of inappropriate location or incorrect care.
Anthracnose usually causes death
Dangerous here is especially the anthracnose, also known as the leaf tan, which is caused by the harmful fungus Discula destructiva and occurs mainly after very rainy summers. An infestation is noticeable in the initial stage by brown leaf tips and leaf spots and eventually leads to necrosis of the shoots and branches. Untreated, this disease always leads to the death of the infected Dogwood, with fungicides usually not help. The only effective method of treatment is a radical pruning of diseased parts of the plant, even far into healthy wood.
Prevent leaf tan
You can, however, prevent the tan by following these rules:
Powdery mildew can be treated well
The powdery mildew - also known as "fair-weather mushroom" - occurs especially in warm and sunny weather and makes itself felt by a greasy, white-gray mushroom lawn on leaves and shoots. Fortunately, this plant disease can fight very well, with not only fungicides have proven successful. Instead, you can spray the dogwood with a mixture of (low-calcium, but not necessarily rainwater!) Water and whole milk in a ratio of 10: 1, which should be done several days in a row. Affected plant parts should be cut away generously and disposed of with household waste.
Eliminate lice with rapeseed oil
Mealybugs are often only recognizable when the whole hornbeam sticks and countless ants gather on it. The persistent miniature animals suck the leaf juice and excrete a sweet liquid, the honeydew. The fight is either biological about parasitic wasps or earwigs - the natural enemies of the lice - or by regularly spraying the entire shrub with rapeseed oil.
Tips
Incidentally, the powdery mildew winters over the fallen leaves in autumn, so that the fungus can re-infest the dogwood the following spring. Therefore, you should always rake together and dispose of all foliage after an infestation - of course not on the compost.