The rose with confidence can be called one of the most whimsical ornamental plants. If the rules of care are not followed, she can get various viral and fungal diseases. Today we offer to talk about rose diseases, methods and means for treatment. We will tell you how to recognize the infection, how to treat the rose bush and what preventive measures you can take. Let's talk about the main pests that are dangerous for this garden crop.
Infectious burn
This disease is also called stem cancer. It affects plants in spring or autumn, during dormancy. Spores penetrate plants through cracks that form after frost in the stem, or through wounds that remain after improper pruning. It is worth noting that an infectious burn extends to absolutely all types of roses, in addition, it can easily spread to crops such as raspberries or blackberries through poorly sanitized tools. The development of this disease of roses is facilitated by humid, calm weather, late fertilizing with nitrogen-containing fertilizers. Florists do not recommend making such dressing after July 20.
How to recognize an infectious burn? There are several signs:
- ulcers of a dark brown color appear on the stem of the rose bush, they encircle the entire stem, and therefore it dies;
- black spots grow on the ulcers, which, in fact, serve as a source of the spread of infection.
Stem cancer treatment
The first thing to do is to immediately remove all diseased shoots. In this case, you must be extremely careful: in no case can you damage the ulcers on the stem. Small wounds can be cleaned to a healthy foundation. A paper knife is ideal for this purpose. Cleared places must be covered with garden var. Florists say that it is imperative to prevent the disease before budding. To do this, you can treat the affected bushes with 3% Bordeaux fluid: such measures will destroy the spores, which means that the pests of roses will not spread them. Until recovery, infected shoots should be sprayed with fungicide weekly.
Preventive actions
Of course, it is much easier to prevent this disease of roses than to treat it. Firstly, in no case do not allow the plant to freeze, due to which cracks in the stem form. Be sure to cover the roses at a temperature not exceeding 10 degrees. Treat the soil with 3% vitriol before shelter. And of course, don't forget to sanitize the tools before pruning the roses.
Rust
One of the most common rose diseases is called rust. It affects the entire terrestrial part of the plant. This usually happens in late April or early May. On the leaves and shoots of roses appear growths that have a yellow color, closer to autumn they turn black. So-called pustules appear on the lower part of the leaf plate, which are dusty with spores and can infect neighboring plants. Rust is dangerous not only to roses, but also to other decorative, coniferous, berry bushes and trees.
The disease can be recognized by the following signs:
- spots of brown and red tint appear on the leaves;
- after a while, the entire leaf plate dries and falls;
- the shape of the shoots changes - they twist, crack, begin to spray spores.
Rust treatment
To treat this disease of roses, you will need drugs that include copper and zinc. It will be useful to spray with Bordeaux liquid. As a preventive measure, thinning out roses from dry leaves and branches is perfect. Gardeners recommend at the very beginning of autumn to carry out treatment with copper sulfate and spray plants with chemical immunomodulators.
Black spotting
Speaking of roses, their diseases and treatment, one cannot but mention the black spotting, which is caused by the fungus Marssonina rosae. This fungus, falling on plants, affects not only the leaf plate, but also the flower petals, and even the sepals. Usually this disease develops in July and August. Spore is promoted by watering.
Recognizing black spotting is quite simple: small dark spots appear on diseased plants, which increase in size extremely quickly. Their diameter can reach 15 millimeters. Conidia with spores of the fungus form on these spots. From the rose bush leaves begin to fall - from top to bottom. Of course, the rose is weakening and slowly dying.
Prevention and treatment of black spotting
It is worth noting that this disease of roses is not treated. In addition, such plants can not be sent to compost, the only option is to burn the affected leaves and shoots. Do not do without treatment with preparations containing copper and zinc. These are usually fungicides such as Fundazole and Kaptan. Before covering the plants for the winter, they should be sprayed with 3% iron or copper sulfate.
Powdery mildew
This disease is also called conidiosis of the rose. It is provoked by a fungus, usually affecting shoots and leaves, less often - buds and rose flowers. Particularly favorable for the development of spores are warm weather and a high level of humidity. The fungus is transported in different ways: through air, water during rain and watering, and various insects. It is worth noting that powdery mildew is dangerous for almost all ornamental plants, vegetables and fruit crops. That is why it is extremely important to start the fight against this disease on time.
You can understand that your rose garden is affected by powdery mildew by the following signs:
- dark red spots appear on the leaves of roses;
- the leaf plate of the plant is deformed, dries and falls;
- the shoot is covered with pustules, in which fungal spores mature.
How to prevent mildew infection
According to flower growers, powdery mildew is easier to prevent than treating plants. Among the recommendations are regular thinning of the bushes, adherence to the timing of applying nitrogen fertilizers. It is important not to overfeed roses with nitrogen supplements. While buds form on the bushes, they must be treated with fungicides. Rose bushes or nets should be sprayed with the daily infusion of mullein, this should be done every two weeks.
Downy mildew
Speaking about the diseases of roses, their description and prevention, one cannot but mention such a problem as peronosporosis, also called downy mildew. Usually this disease appears in early summer, its cause is infection with a fungus. Disputes spread through rain and wind. For the development of downy mildew, a sharp decrease in temperature, increased humidity, an area that is in the shade with poor air ventilation is extremely favorable. It manifests itself as follows:
- shapeless spots appear on the sheet plates, having a saturated red or purple color;
- the foliage of rose bushes loses its shape, curls, falls off;
- the leaves of the buds also die off, before that they darken;
- large cracks form on the stems of roses.
If you take a magnifying glass and look at the back of the sheet, you can see a spider web.
Protective measures and treatment
Roses that are already sick with downy mildew must be completely uprooted and burned, preferably away from healthy plants. If the lesions are small, roses can be treated with fungicides. Strobi or Ridomil Gold are perfect for these purposes. During the formation of buds, flower growers recommend spraying rose bushes with products that contain zinc and copper. It is important and timely treated with special top dressings containing phosphorus and potassium.
Gray rot
This disease also occurs due to infection by a fungus. Its main symptom is that it moves along the plant from top to bottom.
In those areas that are affected, dark spots appear. When they gird the sprouts, they die. Yellowish spots appear on leaves and rose petals affected by gray rot. Subsequently, gray fluffy mycelium appears on these spots. It is worth noting that the development of the fungus can be promoted by prolonged rains, high humidity and lack of ventilation when growing the rosary in greenhouse conditions.
How to cure and prevent gray rot
How to treat roses from the disease? Every two weeks, the bushes should be treated with fungicides such as Fundazole or Euparen. In addition, it is very important to regularly water the earth with various preventive drugs or growth stimulants, which include conventional potassium permanganate. It is recommended to cut and burn the diseased parts of the bush. Another preventive method is the timely cleaning of fallen dry leaves and branches.
Viral Mosaic
This disease appears due to the defeat of the virus, it is able to be transmitted through garden tools - both when pruning and grafting. The description of the disease of roses is as follows: first the lower leaves are affected - small light spots appear on them, after which the foliage of the rose bush completely falls off. Florists warn: the viral mosaic often spreads to other bushes, such as lilacs, raspberries, currants or gooseberries.
Preventive measures
How to handle roses from diseases? In the spring, before the buds open, it is necessary to top-dress: the first time with manure infusion (proportions: 1 part of manure per 20 parts of water), the second, after 2 weeks, with potassium nitrate. It is important to visually check the plants for the presence of a viral mosaic. Do not forget about disinfection: each instrument must be processed in a one percent solution of iodine.
Chlorosis
When considering rose diseases, their description and treatment, it is important to pay attention to chlorosis. This problem is manifested in the yellowing of the leaves of the bush or their whitening.
The main reason gardeners call the lack of iron, magnesium, boron and other chemical elements in the soil. Chlorotic coloration usually spreads throughout the leaf, bypasses only the veins. At the beginning of the disease, the youngest leaves are affected, if chlorosis is not detected in time, small veins will also lose their color, in the future, the tissues will begin to die, the foliage will fall off. So the lack of iron is manifested. If the plant lacks zinc, chlorosis will begin to spread along the edge of the leaf and onto the tissue between the large lateral yolks. But in the center, the leaf will retain its green color. Lack of magnesium leads to the fact that the lower leaves of the rose bush turn yellow and die, the edges of the leaves curl, but the veins remain green.
Chlorosis Control Measures
The main thing that needs to be done, having discovered the above symptoms, is to establish the cause of the disease with chlorosis. This will help the analysis of the soil or the plant. After this, it is necessary to introduce the appropriate nutrients into the soil, of course, within the established doses.
Vascular wilt
This disease is usually characteristic of a Chinese rose. The disease appears due to infection with fungi of the genus Verticillus or Fusarium. In the first case, the lower part of the plant is affected: the leaves begin to curl and turn yellow. Gradually, this process is moving higher and higher. After a short time, only the top of the rose bush will remain green. Fusarium is characterized by slow withering and death of the leaves, while their color does not change at all. The result of the disease is one - the trunk dries out, the rose bush dies.
Disease Control Methods
For the treatment of roses from the disease, such antifungal drugs as Fundazol, Desavid and others will be required. Of course, all affected areas of the plant must be cut off. At the same time, healthy parts should also be captured. Florists say that it is possible to stimulate the protective mechanisms of the shrub itself, for this it must be treated with such drugs as Domotsvet or Epin.
Bacterial spotting
This disease is considered to be a disease of indoor roses. However, it is often found in plants in open ground. Weeping spots with a brown tint appear on the leaves of plants, they gradually increase in size, merge and completely affect the leaf. Usually this disease manifests itself in the second phase of vegetation.
There is only one way to cure a home rose disease called bacterial spotting: it is necessary to remove the affected leaves and shoots, and then spray the indoor flower with preparations that include copper, such as Bordeaux liquid or blue vitriol. Florists recommend reducing the watering of plants infected with bacterial spotting and completely stop spraying until they recover.
Pests
No need to think that this plant is only afraid of disease. Pests on roses appear no less often. They pose the greatest danger during the growing season, when buds, shoots, leaves and flowers begin to develop on the bushes. We bring to your attention a description of pests that usually affect rose bushes.
Rose aphid
This pest settles in the rose garden in huge colonies. Rosaceous aphids are located on the underside of leaves, on young shoots, buds and even peduncles. It is worth noting that the larvae are incredibly small, they are almost impossible to notice. In addition, they very quickly turn into wingless female founders, hatch about 100 larvae, which, in turn, after one and a half weeks can give already new offspring. The rose grower from Sweden has calculated: the generation of one aphid alone during the growing season is capable of producing about two million individuals. These insects suck juice from young organs of roses. The leaves of the plant begin to curl and crumble, the bushes slow down growth, the buds either do not open at all, or give ugly flowers. It is also important that roses, weakened by this pest, do not tolerate winter well.
Processing roses from pests and diseases begins in early spring. You will need contact insecticides. You can spray the plants with a kerosene solution: 10 grams of water will be required for 2 grams of kerosene. No less effective infusion, consisting of 300 grams of softened onions or garlic and 400 grams of tomato leaves. They need to be placed in a three-liter jar, pour water and leave in a warm place for 6 hours. Then the infusion must be thoroughly mixed, filtered and with water brought up to 10 liters. It is recommended to add 40 grams of liquid green soap. With this infusion, it is necessary to process the bushes for 5 weeks - once every 7 days.
Rose circadian
Enormous harm to rose bushes brings and rose rosacea. Under its influence, the leaves become covered with small white dots, lose their decorative effect. Severe damage can lead to yellowing and falling of leaves. In the fall season, each female lays eggs at the tips of rose shoots. In spring, larvae emerge from these eggs, which can subsequently be seen on the underside of the leaves. This pest eats the juice of a rose leaf. The fight against the rosacea cicadas should begin during the period of mass emergence of larvae. According to flower growers, literally two treatments with insecticides will suffice. The interval between them should be about 10-12 days. It is also important to process the territories adjacent to the stands.
Omnivorous cicadas
You can often hear another name for this pest - slobbery pennies. The thing is that the larvae live in foamy secretions that look like saliva. Insects suck the juice from the stems of roses. They are usually found in the axils of the leaves and the underside. If you touch the leaves that are affected by the pest, the larvae will instantly jump out of the foam and hide. The only method to combat the omnivorous cicadas is by spraying with insecticides.
Spider mite
It is difficult to imagine a more dangerous pest than a spider mite. It can cause special troubles to roses, which grow in greenhouses. The thing is that in such conditions it is able to develop throughout the year. Both adult insects and larvae usually damage the bottom of rose leaves. This causes a serious violation of all processes taking place in the plant, including metabolism. Affected leaves begin to become covered with small bright spots, fall off. In addition, pests secrete excrement and weave cobwebs, that is, the leaves become contaminated, dust lingers on them, which means roses lose their decorative effect. Often, inexperienced rose growers complain of a yellow shade of rose leaves, thinking that this is a manifestation of a disease. In fact, this is the work of spider mites, which can be detected using the most ordinary magnifying glass.
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