Roses are one of the most beautiful plants in the garden - with their distinctive flowers and pleasant scents they exude, they transform any outdoor area into an oasis. However, in order to maintain the health and well-being of the plant, you have to pay very close attention to the special features. Anyone who cultivates roses will almost certainly come into contact with some type of disease. Both seasoned professionals and enthusiastic beginners will eventually discover that a disease – star sooty mildew, powdery mildew or rose rust – has affected their rose plants. Discover the 3 most common rose diseases below - you can easily recognize them using these pictures and then fight them successfully.
Rosenrost (Phragmidium mucronatum)
Rose rust, even in its mildest form, is an unsightly disease.
Recognize rose rust
In the worst case scenario, however, rose rust destroys the first host plant and then spreads to the others. Rose plants often lose their leaves and the disease can be identified by the orange or rust-colored spots that appear on the plant's canes and leaves. The affected canes often turn black in the winter months.
Rose rust can overwinter in a diseased plant, but it will also find a safe hiding place in any other area near the host plant that offers some protection from the weather. The good news is that this fungal problem only occurs on roses, meaning it should only be a problem for the other rose plants in your garden.
Dealing with rose rust
The solution to your rust problems lies in developing a comprehensive and careful irrigation method, as is the case with most plant diseases. The spread of this fungal disease can be contained to some extent by removing the infected rose petals.
If you are just starting to design your garden, you should think about choosing rust-resistant plant species to significantly reduce the chances of encountering this annoying disease.
Find out more about how to combat rose rust here.
The 3 most common rose diseases – black mold (Diplocarpon rosae)
This fungal disease can cause shrubs to lose virtually all of their leaves in early fall. As a result, the shrub is significantly weakened and severe dieback occurs.
Rose disease symptoms
Star sooty mold can be recognized by black, circular spots that appear on the upper side of the leaves. The disease often starts at the base of the plant and works its way up. Infected canes have a reddish-purple color. Because infection only begins after the leaves have been wet for several hours, the problem is exacerbated when it rains. It is important to choose a rose variety because certain roses are more resistant to the disease than others.
Fungi are a problem in humid weather and cool nights that prevent moisture evaporation - more likely in spring and fall. Because these seasons are the most favorable conditions for their growth. Sooty mold is more likely to be avoided when temperatures are above about 26 degrees, and disease progression is slowed in dry weather.
Because the fungus can overwinter in infected leaves and canes, it is very likely that it will return to your plants at some point in the future if they were infected in a previous year.
Combat star sooty mold
Some degree of control can be achieved by removing leaves with black spots and by cutting off infected rose bushes in the spring before the buds have had a chance to develop. When watering the plants, be careful not to get the leaves wet and place them in an area where they get plenty of fresh air.
Because the fungus is spread from plant to plant through water droplets that land on diseased leaves, it is important to reduce the chance of infection by avoiding unnecessary watering.
You can use a mixture of about a teaspoon of baking soda and a liter of warm water. This mixture can be sprayed on the plants. Neem oil is another option.
You can discover other control agents here.
Echter Mehltau (Podosphaera pannosa)
You can easily recognize powdery mildew.
Recognize powdery mildew
The disease, called powdery mildew, is caused by a fungus and appears as young leaves turning purple and curling and twisting. As the disease progresses, the leaves will eventually develop a white, powdery coating over the entire leaf. Powdery mildew usually affects the upper part of the plant, unlike star sooty mildew, which often causes the most damage to the lower part of the plant. More mature leaves have a lower risk of being attacked. Mildew can be carried by the wind and grows during periods of warm, dry days followed by cool, damp nights.
The 3 most common rose diseases - how to treat powdery mildew
Eliminate diseased or dead canes to reduce the risk of further fungal infestation. Spraying with natural remedies can help reduce the risk of infection. The product should be applied thoroughly to the new growth to protect it as the new growth is more susceptible to infection. If you want to protect your roses from a variety of diseases, you should plant them in areas that are well ventilated and where the leaves can dry quickly in the early morning.
