Content
- Roses diseases on the trunk
- Damage to the trunk and shoots has many causes
- Leaf and stem rot (Cylindrocladium scoparium)
- Genuine and downy mildew
- Gray horse (Botrytis cinerea)
- Tips
Roses diseases also show up in the trunk
Roses diseases on the trunk
Although rose diseases are mainly found on the upper and lower surfaces of the leaves, they are also common in the shoots and buds of the roses, especially at an advanced stage of the disease. In the case of common roses, of course, the strain itself can also be affected.
Damage to the trunk and shoots has many causes
Not only one or two, but very different causes come into question for the different damage patterns. Most causative pathogens are fungal in nature, but also bacteria or viruses can cause some diseases. However, as fungicidal diseases are more common in roses, we will limit ourselves to this in this article.
Leaf and stem rot (Cylindrocladium scoparium)
This is a rot caused by a fungal pathogen, which primarily affects the leaves and shoots of the rose and can lead to their death. This rose disease occurs only due to a too wet culture, for example because the rose is permanently in wet or too heavy (and thus poorly ventilated) soil. The fungus can penetrate into the roots of the plant, which is why a quick action is essential: usually only a strong pruning and converting the rose helps to a better suitable location.
Genuine and downy mildew
Both mildew species infest not only the leaves, but also the shoots of the rose. In the case of powdery mildew, the buds and flowers can be affected in an advanced infestation. Both diseases, however different in their causes and appearance, are primarily caused by a poorly ventilated location. Ergo helps a good ventilation by pruning and maintaining the planting distance for prevention, also the roses should be injected with preventative plant strengthening agents.
Gray horse (Botrytis cinerea)
Greyish mushroom turf on the leaves, buds and especially young shoots, which often form brown, dry spots and "look like dried", are an indication of an infestation with the botrytis, also known as gray horse. This occurs only in very humid summers or at high humidity, its emergence is also favored by an over-fertilization, especially with nitrogen. Infested shoots must be cut back to healthy wood.
Tips
Small orange-red, calloused spots, which appear in the spring on the rose shoots, are harbingers of the rose rust, which finally attacks the leaves in the summer.