It's annoying when the beautiful roses are suddenly destroyed by fungi. An infestation is usually manifested by different colored spots on the leaves. But with the right care and some preventative measures, every hobby gardener can reduce the risk of illness.
How can you prevent fungal infestation of roses?
To prevent fungal infestation of roses, you should choose robust varieties, remove infected leaves, water the plants at the base, do not over-fertilize and, as a preventative measure, use plant fertilizers such as field horsetail, comfrey or garlic decoction.
These are common fungal diseases
There are three types of fungi that are very common on roses. They are adapted to specific weather conditions and therefore only occur at certain times of the year.
Star sooty dew
Diplocarpon rosae is the cause of one of the most common diseases of roses, which is favored by cool and damp weather. A disease is manifested by irregular spots on the leaves that are gray to purple-black in color and appear radiating at the edge. Yellowish leaf surfaces with reddish nuances are typical. If the infestation is not combated in time, leaves will fall during the summer.
Powdery mildew
This fair-weather mushroom, which has the scientific name Sphaerotheca pannosa var. rosae, finds optimal conditions in humid and warm climates, which is why fungal infestation often appears from June onwards. You can recognize the fungus by a floury white coating on the top of the leaf, which is reminiscent of a mold lawn. If there is a strong expansion, the leaf surfaces curl up slightly. Buds and flowers can also be affected.
Rose Rust
Phragmidium mucronatum develops rusty red to orange spots, the edges of which appear dark. The more the fungus spreads, the more clearly the individual fungal foci merge with each other. Elongated spore beds grow on the underside of the leaf, in which new spores are formed and secreted. The roses react by shedding their leaves prematurely.
What you can do about it
Since fungal infestation has a negative impact on plant he alth, you should address the problem in the early stages if possible. If the disease is not yet advanced, the chances of success are comparatively high.
Fighting Tips:
- choose robust varieties with ADR rating
- carry out regular sprayings with fungicides
- Combined preparations act as universal remedies
Prevention
Remove infected leaves as soon as you see the first signs of a fungal disease. The spores often survive on already infected leaves that fall from the trees. You should not dispose of the plant parts in the compost, as this way the pathogens will spread further in the garden.
Water the plants directly at the base, as a moist environment between the leaves increases the pressure of infection. Watering is recommended in the morning so that the crop can dry out during the day. Be careful not to over-fertilize the trees.
Treatments with plant manure have proven to be successful for many hobby gardeners. Diluted extracts of field horsetail or comfrey are suitable. Garlic decoction is particularly helpful against mildew. You can spray these products into the plants as a preventive measure when the leaves emerge in spring. Repeat the measure every two weeks.
