Rose is considered one of the most common ornamental garden plants. The flower is very capricious and requires special attention and care during the growth and flowering period in order to prevent the occurrence of any diseases. As a rule, the cause of rose disease is non-compliance with growing requirements and unfavorable weather conditions.
Often, the development of diseases causes the formation of fungi, the defeat of the plant by viral and bacterial infections as a result of improper nutrition.
Fungal diseases of roses
The most dangerous among these diseases are spores of rust, powdery mildew and black spot. Many varieties are quite resistant to adverse external influences. Cases of infection are rare, but do not forget to carry out prevention and regularly process rose bushes so that infected areas can be quickly detected.
Rust
Rust covers the underside of leaves and shoots with small dark orange spots. Gradually, diseased bushes darken and wither. The reason for the formation of plaque is an insufficient amount of potassium in the soil, as well as spring frosts and prolonged cold weather.
Control methods and preventive measures
Rose bushes must be regularly treated in order to prevent the occurrence of foci of the disease, for example, spray them with a decoction of horsetail. Infected leaves are sprinkled with sulfur and poured over them with wormwood infusion, for the preparation of which 50 g of dried wormwood is diluted in 10 liters of water and left to ferment. The diluted solution is then used. In severe cases, the plant is treated with Bordeaux liquid or carbendazim. Affected stems and leaves must be removed. Healthy bushes need to be fed with potash fertilizers so that they are resistant to disease.
Powdery mildew
Powdery mildew spores develop in the summer, when hot and dry weather sets in. A thickened planting, dry marginal soil and sudden changes in air temperature have an effect on the active reproduction of the fungus. All vegetative parts of the plant are covered with a white bloom. The leaves gradually curl and begin to fall off quickly.
Control methods and preventive measures
To protect the bushes from damage by powdery mildew, it is necessary to reduce the amount of nitrogen-containing components in the fertilizer and, conversely, add more potassium substances. For prevention purposes, the plant is fed with an aqueous solution of ash with manure. For this, 1 glass of ash and 1 kg of manure are mixed, filled with water and kept for a week. At the first sign of powdery mildew, the leaves are sprayed with carbendazim, after a while the procedure is repeated.If most of the bush is covered with plaque, then it is sprayed with a copper-soap liquid, which includes copper sulfate and green soap in equal proportions. Treatment with other chemicals is carried out strictly according to the instructions and always wearing protective gloves.
Black spot
Rose disease begins with the onset of the summer season and manifests itself in the form of large dark spots that completely affect the bush. The leaves fall off, and the plant dies quickly. Black spot, in contrast to purple spot, is more dangerous.
Control methods and preventive measures
Leaves and stems that have the first signs of the disease must be cut off. The bushes are treated with sulfur-containing preparations and carbendazim. To consolidate the therapeutic effect, spraying is repeated.
There are other types of spotting: septoria, pestalotia, phyllostictosis, and cercospora, which have common properties and signs of disease development. These diseases are characterized by the formation of spots on the leaf blade, which have a dark rim and indistinct outlines. The means of struggle are used the same as in the case of black spot.
Anthracnose
Anthracnose appears as small black spots on the outer surface of the plastic sheet. Many budding gardeners sometimes confuse it with black spot. After a while, the spots change their color. They turn red or purple, and the central part of the spot turns gray.
In their place, holes appear, which interfere with the free distribution of nutrients between all vegetative parts of the bush, which, as a result of the disease, slows down its growth and loses its leaves. Over time, the plant dies. This process is accelerated in wet and cold weather. Roses become most vulnerable to anthracnose in early spring.
The spores of the disease are very resistant to adverse influences and retain their viability even in winter at low air temperatures. With the onset of spring, anthracnose fungi enter the active phase and, together with rainwater, spread further and infect new plant shoots.
Control methods and preventive measures
Diseased leaves and stems must be removed and burned outside the garden to prevent contamination of other plants. In autumn, special attention should be paid to timely harvesting of fallen leaves. For the treatment of bushes, the same drugs are used as in the fight against black spot.
Infectious diseases of roses
The most dangerous are vein and linear mosaics. The vein infection virus changes the color of the veins of the leaf blade. They turn yellow or creamy. Signs of a virus infection appear in late spring, in summer it is almost impossible to see them on the bush. There is a modification of the external structure of the plant, although sometimes this process is not given importance. Linear mosaic virus is a yellow patch that also affects all leaves.
Control methods and preventive measures
To avoid the occurrence of infection, it is required to regularly feed the roses and transplant only healthy bushes. Viruses are transmitted through insects and contaminated garden tools.
Bacterial diseases of roses
Bacteria, getting into the bark and stomata of leaves, have an adverse effect on the plant and multiply rapidly.
Bacterial cancer
Agrobacterium causes the development of the disease and can infect other ornamental plants growing in the garden. They accumulate in the root system of the bush, which decays over time. The disease begins to progress due to frequent feeding with organic fertilizers or external damage to the bark and leaves.
The cause of the spread of stem fire blight is strong wind, rain, insects or the use of contaminated equipment, which must be carefully processed after each pruning of roses. The signs of the disease are darkening of the bark and the formation of cracks on its surface. The leaf blades are deformed and dry out.
Control methods and preventive measures
The parts infected with cancer are cut off, the places of the cuts are treated with a solution of potassium permanganate and then with garden pitch. Pruners, delimbers and other shrub pruning tools are disinfected after each use. Additionally, the bushes are sprayed with a solution of zinc sulfate or foundation.
Some rose diseases occur for other reasons, for example, soil depletion, unfavorable weather conditions. If you choose the wrong site for planting, then in the future problems associated with the development of the plant may also arise.
Withering
After a long illness, rose bushes weaken and begin to fade. Frosts, various infectious and bacterial diseases can lead to the death of even perennial healthy plantations that adorn the garden. Withering first affects the top of the bush and gradually shifts downward. Yellow rose varieties are less resistant to external influences and often lack phosphorus and calcium in the soil.
Control methods and preventive measures
The main preventive measures that reduce the risk of rose diseases are regular feeding of the bushes. If it was not possible to avoid the danger, then all diseased shoots must be quickly cut off in order to prevent further spread of the disease to other healthy parts of the plant.
Transplant disease
Sometimes it happens that the transplanted roses do not take root and gradually wither away, although the old bushes located nearby feel great. This is due to the depletion of the soil. Roses that have been growing in this area for a long time have already learned to adapt. They have enough nutrients in this environment, but new neighbors need feeding to recuperate after transplanting.
Control methods and preventive measures
To increase the fertile properties of the soil, it is fed with any organic fertilizer, for example, compost, humus. Manure is used only rotted so as not to burn the roots.
