Fungal diseases of roses – prevention and treatment

One of the major problems faced by gardeners when growing roses is their high susceptibility to fungal diseases.

The most common are powdery mildew, rust, black spot and infection burn. To disease was the most effective, it is important to diagnose and time to take action.

Among these diseases the first place is powdery mildew. The development of its more intense on young shoots. An important feature of the disease is that the fungus does not need the moisture and it can develop on dry leaves, so quite often, powdery mildew is becoming an epidemic.

A mass lesion of this disease occurs after hot, dry weather, which reduces the number of healthy leaves, roll and dried them, and consequently to a General weakening of the plant.

The appearance of the rose leaves much to be desired, as the leaves and stems they covered with white powdery bloom, which leads to rapid spread of infection to neighboring plants.

This disease is much easier to prevent than to fight it. Therefore, it is important to know some features of the fungus. First and foremost it should be noted that the development of the disease is positively influenced by the absence of direct sunlight, air temperature of 20-25 °C and humidity not less than 40%.

In different climatic zones powdery mildew of roses begins is manifested mainly in may and develops almost all summer.


  • Selection of disease-resistant varieties.
  • Planting roses in well-drained soils and in areas with adequate lighting.
  • The optimal planting scheme (for flowerbed dwarf varieties of roses 30-40 cm between plants for vigorous varieties, 40-60 cm) to provide a good produvaemosti plants.
  • Making the recommended norms of mineral fertilizers, especially nitrogen. Remember that it is better for underfeeding the plant than overfeed. A valid option is to replace mineral fertilizers by organic (compost, diluted chicken manure).
  • Pruning and burning of affected parts of the plant. At strong development of disease will have to remove and burn the entire hive.
  • Watering should be done only in the morning hours, which contributes to the drying of water on leaves during the day.

Control measures

If prevention does not help, you have to use chemical method of dealing with mildew:

  • Spraying with 1% soda solution with the addition of soap with a weak defeat.
  • At strong development of disease requires treatment with fungicides (Topaz, Fundazol) or chemical fertilizers (on the basis of bacteria no chemical components), for example, fitosporin-M. the Spraying of the drug carried out before and after flowering of roses, the interval of 10-15 days.

The second in their spreading the disease rose rust. This fungal disease can be recognized by the appearance of the typical orange-yellow spores on the rose stems and lower leaves. The most dangerous the disease is for everbearing varieties.


To prevent rust apply the same preventive measures as in the defeat of powdery mildew.

Control measures

If, however, to avoid developing the disease has failed, then you can spray the plants Phytosporin-M, Topaz, and other fungicides of similar actions.

Black spotting (marssonina) is also considered a fairly common disease. A typical sign of this disease are purplish-brown rounded spots on the leaves which then turn black. Eventually the leaves fall off, slowing the development of young shoots and plants lose hardiness.


One of the effective ways of prevention can be called a leaf collecting roses and burning them (as they are the main source of infection in the spring). In addition, the loosening of the soil in late fall will contribute to the freezing of the fungus.

Control measures

To combat black spot of rose a few times sprayed with a fungicide (Profit, Ridomil gold, Topaz, Ambulance), respecting the principle of alternation.

Infectious burn (cancer stem) roses must also be attributed to the most harmful diseases of these plants. The manifestation of the disease can be noticed in early spring when the rose bushes are formed of brown spots with reddish-brown edging banding shoots.

The development of a fungal infection leads to the cracking of bark, resulting in formation of a rather deep wounds on the stem. Therefore, the disease and received a second name – stem cancer.


In order to prevent cancer of the stalk to cover the bushes for the winter in dry weather, and ventilate them during the thaw, and not to exceed the dose of nitrogen fertilizer, and additionally to feed the roses potash fertilizers.

Control measures

Disease resistant varieties of roses at the moment does not exist. If the plant is already infected sablevm cancer, most gardeners consider it inappropriate to treat it. All the diseased plants are advised to uproot and burn.

Care for roses properly and they really will become the Queen of your garden.