Rose diseases appear primarily on the upper and lower sides of the leaves, but often - especially in an advanced stage of the disease - also on the shoots and buds of the roses. In the case of standard roses, the stem itself can of course also be affected.
Rose diseases also show up on the trunk
There are many causes of damage to the trunk and shoots
Not just one or two, but very different causes come into question for the different types of damage. Most of the causative pathogens are fungal in nature, but bacteria or viruses can also trigger some diseases. However, since fungicidal diseases are more common in roses, we will confine ourselves to them in this article.
Leaf and stem blight (Cylindrocladium scoparium)
This is a rot caused by a fungal pathogen that primarily affects the leaves and shoots of the rose and can lead to their death. This rose disease only occurs because the culture is too wet, for example because the rose is permanently in wet or too heavy (and therefore poorly ventilated) soil. The fungus can penetrate into the roots of the plant, which is why quick action is essential: Usually only a strong pruning and moving the rose to a more suitable location helps.
Powdery and downy mildew
Both types of mildew attack not only the leaves, but also the shoots of the rose. In the case of powdery mildew, the buds and flowers can also be affected if the infestation is advanced. Both diseases - as different as they may be in their causes and their appearance - are primarily caused by a poorly ventilated location. Ergo, good ventilation by pruning and maintaining the planting distance helps preventively, and the roses should also be sprayed with plant strengtheners as a preventive measure.
Gray mold (Botrytis cinerea)
Grayish growths of fungus on the leaves, buds and primarily young shoots, which often also form brown, dry spots and appear "as if dried out", are a sign of an infestation with botrytis, also known as gray mould. This only occurs in very humid summers or when the air humidity is high, and its formation is also favored by over-fertilization, especially with nitrogen. Affected shoots must be cut back to healthy wood.
tips
Small, orange-red, calloused spots that appear on rose shoots in spring are harbingers of rose rust, which eventually affects the leaves as well in summer.