Rose rust is a dangerous but rather rare disease. The causative agent of this disease are fungi of the genus Phragmidium disciflorum, which affect almost all plants. In late April – early May on the kidneys that bloom and the root neck you can find a bright yellow spore mass. Sick areas of the bark crack, shoots become crooked and thicken, and then dry out. A little later on the bottom side of the sheet there are clusters of orange-yellow spores. On the top of the sheet, yellowish-red spots become visible, which gradually cover the entire sheet. Excess nitrogen and rainy summers contribute to rust. The rust of roses is easily transferred from plant to plant, and weakens them greatly. As a result, roses shed most of the leaves and cease to bloom. If the bush is severely affected by the disease, then it dies.
Anti-rust treatment methods
The rust pathogen overwinters in the form of spores or mycelium on diseased stems. The first thing to do to prevent the development of the disease is to collect the affected leaves and cut out the diseased shoots, and then burn them. For prophylaxis, it is necessary to conduct foliar dressings before each flowering with a 0.3% solution of superphosphate and 0.3% solution of potash nitrate until the leaves are completely wetted. Small local lesions on the bushes can be sprayed with 0.7-1% Bordeaux mixture.