Rose can definitely be called one of the most whimsical ornamental plants. If the rules of care are not followed, she can get sick with various viral and fungal diseases. Today we offer to talk about diseases of roses, methods and means for treatment. We will tell you how to recognize an infection, how to treat a rose bush, and what preventive measures can be taken. Let's talk about the main pests that are dangerous for this garden crop.
Infection burn
This disease is also called stem cancer. It affects plants in spring or autumn, during dormancy. Through the cracks that form after frost in the stem, or through the wounds that remain after improper pruning, spores enter the plants. It is worth noting that the infectious burn extends to absolutely all types of roses, in addition, it can easily spread to crops such as raspberries or blackberries through baddisinfected tools. The development of this disease of roses is facilitated by wet calm weather, late fertilizing with fertilizers containing nitrogen. Flower growers do not recommend making such top dressing after July 20.
How to recognize an infectious burn? There are several signs:
- dark brown ulcers appear on the stem of a rose bush, they encircle the entire stem, and therefore it dies off;
- black dots grow on ulcers, which, in fact, serve as a source of infection.
Treatment of stem cancer
The first thing to do is to immediately remove all diseased shoots. In this case, you need to be extremely careful: in no case can you damage the ulcers on the stem. Small wounds can be cleaned to a he althy base. A paper cutter is ideal for this purpose. Cleaned places must be covered with garden pitch. Florists say that it is extremely important to prevent the disease before bud break. To do this, you can treat the affected bushes with a 3% Bordeaux liquid: such measures will destroy the spores, which means that rose pests will not spread them. Until recovery, infected shoots should be sprayed with a fungicide weekly.
Prevention measures
Of course, it is much easier to prevent this disease of roses than to treat it. First, in no case do not allow the plant to freeze, due to which cracks form in the stem. Be sure to cover roses at temperatures no higher than 10 degrees. Before the shelterwork the soil with 3% copper sulphate. And, of course, do not forget to disinfect the tools before cutting roses.
Rust
One of the most common rose diseases is called rust. It affects the entire ground part of the plant. This usually happens in late April or early May. On the leaves and shoots of roses, growths appear that have a yellow color; closer to autumn, they turn black. On the lower part of the leaf plate, so-called pustules appear, which are dusty with spores and can infect neighboring plants. Rust is dangerous not only for roses, but also for other decorative, coniferous, berry bushes and trees.
You can recognize the disease by the following signs:
- brown and red spots appear on the leaves;
- after a while the entire leaf plate dries up and falls off;
- the shape of the shoots changes - they curl, crack, start spraying spores.
Rust treatment
To treat this disease of roses, you will need preparations that include copper and zinc. Spraying with Bordeaux liquid will also be useful. As a preventive measure, thinning roses from dry leaves and branches is perfect. Gardeners recommend at the very beginning of autumn to treat with copper sulphate and spray plants with chemical immunomodulators.
Black spotting
Speaking of roses, their diseases and treatment, one cannot fail to mention the black spot, which is caused by the fungus Marssonina rosae. This fungus, getting on plants, affectsnot only a leaf plate, but also flower petals, and even sepals. Usually this disease develops in July and August. Irrigation promotes the spread of spores.
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. On these spots, conidia with spores of the fungus are formed. Leaves begin to fall from the rose bush - from top to bottom. Of course, the rose weakens and slowly dies.
Prevention and treatment of black spot
It is worth noting that this disease of roses is not treated. In addition, such plants cannot 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. Usually these are fungicides such as Fundazol 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 rose conidiasis. It is provoked by a fungus that usually affects shoots and leaves, less often buds and flowers of roses. Warm weather and high levels of humidity are especially favorable for spore development. The fungus is transferred in different ways: by air, by water during rain and watering, by various insects. It should be noted that powdery mildew is dangerous for almost all ornamental plants, vegetable and fruit crops. That is why it is extremely important to start the fight against this disease on time.
Understand thatyour rose garden is affected by powdery mildew, you can by the following signs:
- dark red spots appear on rose leaves;
- leaf plate of the plant is deformed, dries up and falls off;
- the shoot is covered with pustules in which fungal spores mature.
How to prevent powdery mildew infestation
According to flower growers, powdery mildew is easier to prevent than to treat plants. Among the recommendations are regular thinning of the bushes, compliance with the timing of the application of nitrogenous fertilizers. It is important not to overfeed roses with fertilizers containing nitrogen. While buds are forming on the bushes, they must be treated with fungicides. Spray rose bushes or nets with mullein daily infusion every two weeks.
Downy mildew
Speaking about diseases of roses, their description and prevention, one cannot fail to mention such a problem as peronosporosis, also called downy mildew. Usually this disease appears in early summer, it is caused by infection with a fungus. Spores are spread by rain and wind. For the development of downy mildew, a sharp drop in temperature, high humidity, an area that is in the shade, with poor air ventilation is extremely favorable. It appears as follows:
- shapeless spots appear on the leaf plates, having a rich red or purple color;
- leaf of rose bushes loses shape, twists, falls off;
- leaves of buds also die off, before that they darken;
- on stems of roseslarge cracks form.
If you take a magnifying glass and look at the back of the leaf, you can see the spider web.
Protection measures and treatment
Roses already infected with downy mildew should be completely uprooted and burned, preferably away from he althy plants. If the lesions are small, you can treat the roses with fungicides. For these purposes, "Strobi" or "Ridomil Gold" are perfect. During the formation of buds, flower growers recommend spraying rose bushes with products that contain zinc and copper. It is important and timely to treat with special dressings containing phosphorus and potassium.
Grey Rot
This disease also occurs due to infection with a fungus. Its main feature is that it moves down the plant from top to bottom.
Dark spots appear on those areas that are affected. When they encircle 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 facilitated by prolonged rains, high humidity and lack of ventilation when growing a rose garden in greenhouse conditions.
How to cure and prevent gray mold
How to treat roses from the disease? Every two weeks, bushes should be treated with fungicides such as Fundazol or Euparen. In addition, it is very important to regularly water the earth with variousprophylactic drugs or growth stimulants, which contain ordinary potassium permanganate. It is recommended to cut and burn diseased parts of the shrub. Another way to prevent is the timely cleaning of fallen dry leaves and branches.
Viral mosaic
This disease appears due to the defeat of the virus, it can be transmitted through garden tools - both when pruning and when 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. Flower growers warn: the viral mosaic often spreads to other bushes, such as lilacs, raspberries, currants or gooseberries.
Prevention measures
How to treat roses from diseases? In the spring, before the buds bloom, it is necessary to feed: the first time with manure infusion (proportions: 1 part of manure to 20 parts of water), the second, after 2 weeks, with potassium nitrate. It is important to visually inspect plants for the presence of viral mosaics. Do not forget about disinfection: each tool must be treated in a 1% iodine solution.
Chlorosis
Considering diseases of roses, their description and treatment, it is important to pay attention to chlorosis. This problem manifests itself 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, bypassing only the veins. At the onset of the diseasethe 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 off, the foliage will fall off. This is how iron deficiency manifests itself. If the plant does not have enough zinc, chlorosis will begin to spread along the edge of the leaf and on the tissue between the large lateral yolks. But in the center, the leaf will retain a green color. Lack of magnesium causes the lower leaves of the rose bush to turn yellow and die, the edges of the leaves curl, but the veins remain green.
Chlorosis control measures
The main thing to do, having discovered the above symptoms, is to establish the cause of the disease with chlorosis. This will help the analysis of the soil or plants. After that, it is necessary to add the appropriate nutrients to the soil, of course, within the prescribed doses.
Vascular wilt
This disease is usually found in Chinese roses. The disease appears due to infection with fungi of the genus Verticillium 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 wilting and death of the leaves, while their color does not change at all. The result of the disease is the same - the trunk dries out, the rose bush dies.
Disease control methods
For the treatment of roses from the disease, antifungal drugs such as Fundazol, Dezavid and others will be required. Of course, all affected areas of the plant must be cut off. Whereinhe althy parts should also be captured. Flower growers say that it is possible to stimulate the protective mechanisms of the shrub itself, for this it must be treated with preparations such as Domotsvet or Epin.
Bacterial spotting
It is generally accepted that this disease is 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 the growing season.
There is only one way to cure a home rose disease called bacterial spotting: you need to remove the affected leaves and shoots, and then spray the indoor flower with preparations that include copper, such as Bordeaux liquid or copper sulfate. Florists recommend reducing watering of plants infected with bacterial spot and completely stop spraying until they recover.
Pests
No need to think that only diseases are terrible for this plant. 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 the pests that usually affect rose bushes.
Rose aphid
This pest settles in huge colonies in the rose garden. Rosan aphid is located on the underside of the leaves, on young shoots, buds andeven flower stalks. It is worth noting that the larvae are incredibly small, they are almost impossible to notice. In addition, they very quickly turn into wingless founding females, give birth to about 100 larvae, which, in turn, can give birth to new offspring after one to a week and a half. A rose grower from Sweden calculated that a generation of one aphid during the growing season alone is capable of producing about two million individuals. These insects suck the juice from the 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: 2 grams of kerosene will require 10 liters of water. No less effective is an 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 to bring the volume to 10 liters. It is recommended to add 40 grams of liquid green soap. Bushes must be treated with this infusion for 5 weeks - once every 7 days.
Rose Leafhopper
Rose leafhopper also brings great harm to rose bushes. Under its influence, the leaves become covered with small white dots, lose their decorative effect. severe damagemay cause yellowing and leaf drop. During the autumn season, each female lays her eggs on the tips of rose shoots. In the spring, these eggs hatch into larvae, which can later be seen on the underside of the leaves. This pest feeds on the juice of a rose leaf. The fight against rose leafhopper should begin during the period of mass appearance of larvae. According to flower growers, literally two treatments with insecticides will be enough. The interval between them should be about 10-12 days. It is also important to cultivate the territories adjacent to the plantations.
Omnivorous leafhopper
You can often hear another name for this pest - slobbering pennitsa. 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 way to control the omnivorous leafhopper is to spray with insecticides.
Spider mite
It is hard to imagine a more dangerous pest than the spider mite. It can cause particular trouble to roses that 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 underside of rose leaves. This causes a serious disruption 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 excrete excrement and weavecobwebs, that is, the leaves become dirty, dust lingers on them, which means that roses lose their decorative effect. Often, inexperienced rose growers complain about the yellow tint of rose leaves, thinking that this is a manifestation of some kind of disease. In fact, this is the work of spider mites, which can be detected using the most ordinary magnifying glass.
How to deal with this pest? First of all, it is important to note that the development of spider mites will be deterred by regular spraying with cold water. You need to spray the lower surface of the leaves at least three to four times a day. In closed ground conditions, you will need drugs such as Vermitek, Fitoverm. It is worth noting that they do not affect eggs and larvae that feed or expect to molt. If the temperature in the greenhouse is +20 °C, you will need to carry out at least 3 treatments, the interval between which should be 9 days. If the temperature reaches +30 ° C, it is necessary to carry out 4 treatments with an interval of three days. If the rose garden is planted in open ground, acaricides will come to your aid. You can spray plants with "Acrex", the concentration of which is 0.08%, "Isofen" (0.05%).
Now you know everything about the most common diseases and pests of roses: description, methods of control and prevention. So, you can create a rose garden - he althy and incredibly attractive!
