Despite the reputation of capricious impatience, the rose can adapt well to Spartan conditions, withstanding short-term drops in temperature to -5 ° C in summer during unexpected frosts. If you want to fully enjoy its splendor, you will have to make additional efforts: provide it with a comfortable living space, top dressing, timely watering and, of course, protection from diseases.
The most common diseases of roses
Roses can get sick too. The plant cannot complain of being unwell, so pay more attention to its appearance. After all, any sore sooner or later will manifest itself. Dividing all the diseases of this culture into groups, we get:
- fungal diseases;
- root rot;
- diseases caused by bacteria;
- viral diseases;
- non-infectious lesions.
Among the diseases caused by fungi are the common powdery mildew, rust, several varieties of bark necrosis, gray rot, drying of branches, various types of spotting, and others. In fact, white sclerocial rot, which is one of the root rots, is also a fungal disease that occurs in the roots of roses invisible to the eye.
Pathogenic bacteria can easily kill a plant. An example of such a disease is bacterial cancer. Viruses cause jaundice, leaf streaks and viral wilt. These diseases are difficult to stop, but they can be prevented if prevention is not forgotten.
Under the influence of external factors, the plant often develops non-infectious diseases. For example, sunburn, root clogging, natural aging. There is a considerable list of diseases associated with a deficiency of a certain trace element that is necessary for the life of a plant: potassium, phosphorus, manganese, iron, nitrogen, calcium, magnesium.
Some diseases lead to the death of the plant, others are easily curable, and others can be avoided altogether if preventive measures are taken. Consider three common ailments that are of fungal origin. They are not only possible, but also necessary to treat.
Powdery mildew — three stages of the problem
Most often, powdery mildew appears at the very beginning of summer after a series of heavy rains, when the air warms up to 18 ° C and above. The causative agent of the disease is the spores of Sphaerotheca pannosa, which could, for example, get on the stems of the plant in advance, and even overwinter on them in anticipation of a favorable moment for the manifestation of their activity.
How the disease manifests itself
In the first stage, the disease is secretive. However, looking closely at the leaves of roses, you can notice slight changes in their colors and shape. The lower surface of the affected leaf acquires a brownish color, and its edges rise up, forming a boat.
The second stage of the disease is impossible to ignore. Spots of a whitish coating are formed on the leaf plate, similar to traces of spilled flour. These are the spore colonies that can be seen without a microscope.
The transition of the disease to the third stage is manifested by an increase in lesions. Now they have acquired a gray color, which indicates the readiness of the spores to be transferred to infect neighboring plants.
Prevention and treatment
To combat powdery mildew, two drugs are used, the effectiveness of which depends on the stage of development of the problem.
- «Topaz» is a systemic fungicide that is used to prevent the disease. Spraying with the preparation should be carried out 2-3 times with two-week breaks. The first treatment should coincide with the beginning of the growing season of roses.
- «Strobi» is a therapeutic and eradicating systemic fungicide. It is used when the disease has already been diagnosed. It is effective at any stage of treatment.
If you are going to process the Strobi plant, add a preparation to the finished solution that can increase the immunity of garden crops. For example, «Epin» or «Zircon».
Rust occurs in June
Rainy summers and an excess of nitrogen in the soil can provide favorable conditions for the development of Phragmidium disciflorum spores. Most often they are activated in mid-June.
The first manifestations of the disease
The disease can be identified by spots of a characteristic «rusty» color and rounded shape that appear on the leaves and branches of the plant.
If timely action is not taken, the spots will begin to merge, forming brownish surfaces that can affect the entire plant, spread to neighboring bushes and destroy many roses.
Prevention and treatment
Preventive measures to combat rust begin in early spring. It is necessary to spray the bushes themselves and the land surrounding them with a solution of copper sulfate (1%). And at the end of autumn, carry out the same treatment with iron sulfate (3%).
For prevention, a 1% solution of Bordeaux mixture is also used. They are treated with roses before and after flowering.
If prevention is late, and the disease has already shown itself, it is necessary to use fungicides:
- «Penconazole» («Topaz»);
Preparations should be used, guided by the instructions attached to them.
Spotting — a disease of the second half of summer
Black spot is one of the most common rose problems. It manifests itself precisely when flower growers decide that the main troubles are behind — in the second half of the rainy summer.
Characteristic signs of the disease
Black blurry spots on the surface of rose leaves are a characteristic sign of black spot. In the process of development of this disease, the leaves of the plant begin to turn yellow and fall off. Leaves are affected from the bottom up. If urgent treatment is not started, the plant may completely lose foliage and die.
How to treat spotting
All fallen and affected foliage should be carefully collected and burned. Until the problem is finally resolved, this process must be repeated: the leaves are collected and burned.
A diseased bush should be immediately treated once with one of the preparations containing copper:
- Bordeaux liquid;
- copper sulfate;
- «Abiga Peak».
As in previous cases, the plant must be treated with fungicides based on triazole or mancozeb. It is recommended to shed the earth around the bush with «Fitosporin — M».
Since any disease is easier to prevent than to cure, the rules for growing roses should not be neglected. Keep a distance when planting bushes, choose well-drained and well-lit areas for them. Try top dressing and watering plants to do at the root.