Contents
Black spot is a common disease that affects leaf blades. Pathology is the result of the development of the pathogenic fungus marssonina rosae, which is the causative agent. Spores overwinter on the plant without problems and begin vigorous activity after warming.
What is rose disease
The disease is one of the most common in roses. The disease is most dangerous for young, recently planted seedlings. First, the decorative effect is lost, and then the leaf plates begin to die off. The plantation develops much more slowly, and young branches shed their greenery.
Most of the bushes are not strong enough to survive the winter with symptoms of infection. The fungus is carried along with:
- dew;
- insects;
- wind;
- birds.
The dark spots keep getting bigger. In a short time, they grow to such a size that they cover the entire surface of the foliage.
Important. There are no varieties that are completely immune to disturbance. Any species has a risk of pathology.
The peak incidence occurs in mid-summer. It is at this time that gardeners most often notice signs of a violation.
Causes of black spot on roses
There are a number of reasons that increase the risk of spotting. These include:
- Preservation of warm humid weather for a long period of time. This creates favorable conditions for the development of the fungus. It multiplies several times more actively.
- The growth of shrubs in a lowland or too thickened place. This makes air circulation difficult. Moisture does not evaporate so actively, and this also contributes to the creation of favorable conditions for reproduction.
- Wrong feed. Moreover, the disease can appear both from an excess and a lack of fertilizers.
- Lack of calcium. This is another common cause of the violation.
The root causes also include poor lighting, lack of wind, potassium deficiency, excess nitrogen fertilizers.
Deviation symptoms may occur after the end of the first flowering wave. If you do not cope with it in time, then the planting can completely die.
black spot symptoms
Symptoms of the disease are at first unexpressed, but over time they will become stronger. First, small spots of various sizes appear. They darken over time. The diameter of the affected areas is 5-16 mm. Brown formations turn into black dots.
After a week, the spots grow together. The leaf plate acquires a dirty brown tint. The leaves begin to dry and the bush sheds them.
Occasionally, bumps form instead of spots. Symptoms spread from bottom to top. The tip is the last to suffer.
In humid and hot weather, signs may appear after 10 days. The plant looks sick. This is due to the reduction in the number of flowers and the loss of foliage.
Sometimes only a bare stem may remain. The fungus easily tolerates a decrease in temperature, so the disease can become more active next season.
When sick, the shoots become woody. Later they dry out. Symptoms may also extend to the sepals.
Disease danger for roses
Illness is the greatest danger. The main problem is that the plantation ceases to develop normally. Affected bushes stop growing. Roses do not woody and shed all leaf plates.
In cold weather, plants are more likely to freeze. With the complete absence of therapy, the bush will die within 2-3 years.
If you do not follow the instructions for treatment, then the pathology will spread throughout the garden. Spores will destroy all the flowers in the area.
Resistant varieties of roses
Roses that cannot be affected by the fungus do not exist. However, there are varieties that are more resistant to certain diseases. Such varieties are the result of the hard work of breeders who work year after year to improve the quality of plantings.
With an increased likelihood of developing spotting on the site, it is worth abandoning the cultivation of varieties of tea, climbing and polyanthus roses. Such plants have a weak resistance to the fungus.
Important. The most resistant varieties include Leonardo de Vinci, Quadra, La Perla, Nostalgie, Grande Amore and others.
The least likely to become infected are those roses that are distinguished by glossy leaves. With proper care, such bushes with almost 100% probability will not be susceptible to pathology. The main thing is to create favorable conditions for their growth.
How to deal with black spot on roses
Treatment of the disease requires special attention. It includes:
- compliance with preventive measures;
- application of specialized chemicals;
- use of folk methods.
The sooner the gardener starts care to eliminate the pathology, the higher the chance of saving the roses. It is recommended to resort to treatment already at the first signs of a violation.
Preparations
The most effective way to deal with a pest is to use specialized chemicals. They are aimed at fighting the fungus. At the same time, they will not have any negative impact on the flower itself.
To eliminate the fungus, the use of a chemical is required. You can find a preparation of this group in any garden store. One application may be enough to completely deal with the pathogen. The main thing is to follow the recommendations from the manufacturer.
The following medications are usually recommended:
- Medicines containing copper. These are protective chemicals. The chemical has good retention. They control not only fungal, but also bacterial infection. The only drawback is that the components can cause burns in young plantations.
- Systemic contact drugs. Systemic medicine is effective against various fungal abnormalities. It is combined. Active additives penetrate into the tissues of the plant.
It is recommended to use different types of drugs so that the pathogen does not have time to adapt to the additives. So the treatment will be most effective.
Topaz for roses from black spot
The medication includes penconazole. The hazard class of the chemical is 3. This is one of the strongest drugs for the disease.
It is easy to prepare a solution. To do this, dilute 8 ml of the product in a bucket of water. It is required to make 3 sprayings with an interval of 10 days.
Is fast
The fungicide belongs to the 3rd hazard class. For 1 bucket of water, it is enough to use 2 ml of the drug. It is allowed to do 3 therapies with a break in a week.
abiga peak
The drug from the fungus refers to copper-containing chemicals. Its base is copper chloride. The drug has a 3 degree of danger. No more than 50 g of the substance is added to one bucket of water. No more than 2 treatments should be carried out with a break of about a week. Too frequent use is contraindicated.
Ridomil Gold
The drug is a systemic contact. To cope with the disease, mix 4 g of the component with a bucket of water. Spray the garden once a week. To save the landing, usually 1 procedures are enough. You need to use the product no more than 2 times.
Bordeaux liquid
The chemical has hazard class 2. It is effective but toxic.
In most cases, the mixture is used when the disease is already very advanced. Affected leaves after treatment do not restore their original appearance, but become quite healthy. Affected mass will no longer turn green.
The substance should be stirred as follows: mix 10 g of medicine with 10 g of lime and pour a bucket of water.
Important. The finished mixture can be used on the territory only twice on the site. Apply it only with a break of 10-12 days.
Fundazole
The fungicide contains benomyl. Hazard class – 2-3. The systemic drug is used only for the ground part. The number of impacts depends on the degree of neglect of the state.
During the summer, the fungicide can be used up to 4 times. It is important to take a break for at least 1-3 weeks.
inkstone
The disease is treated with a mineral fungicide quickly, because immediately after it hits the plant, it penetrates the cells. The mixture protects not only from the disease, but also from pests.
It was not without its shortcomings. Substances provide protection against ailments and pests for only two to three weeks. In the future, there is a repeated risk of infection.
It is best to water the bushes using this drug only in the autumn. In the summer it will have to be abandoned. The recommended proportion is 100 g of medication per 1 bucket of liquid. With an increase in dosage, there is a risk of harming the bush.
The mixture that will run off the edges and hit the ground will act as a fertilizer.
Important. If the bushes are indoor, then the concentration should be lower.
Falcon
Falcon is a three component fungicide. It is used to eliminate not only diseases of roses, but also cereals, beets, grapes. The drug is low toxic to the soil and economical in consumption.
Falcon treats not only spotting, but also powdery mildew, rust. For processing, you need to prepare a solution at the rate of 5 ml per 10 liters of water. It can be used both for the elimination of the disease and prevention. The main thing is to follow the basic recommendations.
Previcur Energy
Previkur Energy is a drug that significantly increases the immunity of roses. For an effective fight, 1,5 ml of the substance should be mixed with 200 ml of liquid. When it is completely dissolved, the volume should be brought to 1 liter.
For the entire period, it is possible to carry out only 2 treatments. At the same time, at least 2 weeks should elapse between them. Otherwise, other problems will be added.
If the drug is injected directly into the soil as a top dressing, then the dosage is 15 ml per 1 bucket of water. In this case, the mixture is poured directly under the bushes.
horde
It is a fungicide based on cymoxanil and copper oxychloride. To eliminate the disease, the dosage should be strictly followed. 1 g of medicine for the treatment of roses should be added to 25 bucket of water.
The maximum allowable number of treatments is 3. It is impossible to exceed the recommended number due to the risk of a negative effect on roses. The interval between the use of the Order should be 2 weeks.
Profit Gold
The substance is dissolved in water in an amount of 4 g. The disease is fought with an interval of 1-1,5 weeks.
The maximum number of treatments is 3. The advantage is that the composition contains trace elements that improve the functioning of enzymes.
Important. Profit Gold is highly toxic to both humans and animals, so treatment should be carried out as carefully as possible. Be sure to follow all safety measures.
The mixture is also actively used to eliminate and prevent late blight in plants.
Biological agents
In case of illness, biological fungicides can be preferred. Their main advantage is a more gentle effect. Biological mixtures include:
- Fitosporin-m;
- Zircon;
- Siliplant.
Biotreatment is carried out every 5 days. The total amount of use of the mixture should be at least 4 times.
Until the next use, the biological mixture is poured directly under the root. For effective impact, it is important to collect all infected leaves and dispose of them. The soil is watered with copper-containing compounds. It will also be useful to use the Healthy Garden. It will increase the protective functions of the plantation.
Ineffective means
With the development of the disease, you should understand the treatment options. Not all solutions, according to the comments of experienced gardeners, will be able to provide the expected help. With their use, the disease will progress, and there will be no significant improvements.
Less effective solutions and additives include:
- Wood ash. When used correctly, it is very useful, but not in the case of spotting on rose bushes. It is most advisable to use it for feeding roses in August or early autumn. It will be a natural fertilizer for plants and provide quality care.
- Herbal infusions for plants based on nettle, horsetail, onion peel, wild rose, etc. You can process flowers with them. However, it is better to use the infusion additionally in conjunction with fungicides, since the effectiveness is minimal. You can also use it not from the black spot of roses, but as a good plant nutrition.
- Decoctions of citrus fruits for plants. You should not expect a special result if the landing is treated with such a medicine. The disease will not disappear under the influence of citrus fruits.
- Alirin and Gamair. According to reviews, spotting often develops on flowers precisely after treatment with these compounds for plants.
- Glyocladin. An excellent option for preventing root rot in phlox, but completely useless for spotting in rose bushes.
It is better to spray roses with proven anti-blotch formulations than to use those whose effectiveness for plants is not proven or minimal.
Folk remedies
Folk methods are best used in combination with chemicals. In this case, the treatments will be really effective and the disease will be quickly eliminated.
It would be advisable to use folk methods at the initial stage of development of rose spotting. The treatment of leaves with horsetail helps. It is required to take a dry plant in an amount of about 150 g and mix with a bucket of water. It is left for a day. A day later, the container is put on fire and the contents are brought to a boil. The finished medicine is diluted in a ratio of 1 to 10.
A good option would be to use onion peel. 100 g of the product is poured into half a bucket of water. A day later, the mixture with the husk is filtered and 5 g of soap are added. Processing is carried out three times with a break of a week. For a better fight against black spot, it is necessary to sprinkle a piece of soil under the plant with wood ash.
Important. Regardless of what will be used on the territory, leaves and buds damaged by black spot must be collected. They are burned.
It is better to use any folk methods as a preventive measure. Leaves, shoots, soil can be treated with non-traditional medicines. Such a measure will strengthen the immunity of the shrub.
In the spring
When fighting a disease in roses, it is imperative to take into account the time of year. The list of recommended medicines strongly depends on when the therapy is carried out – in the fall or, for example, in the spring. In the spring, the disease does not manifest itself actively. Spores overwinter well and after the snow melts, they only begin their activity on the rose.
After warming, the first control measures should begin. Before the start of the growing season, pruning is carried out. All branches and shoots are cut from the plant to healthy wood. As a preventive measure, the rose itself and the ground around it are treated with any chosen solution. Similar actions are performed in the fall.
Lettom
In summer, the disease progresses most strongly. In July, weaker varieties suffer from black spotting of roses, and stronger ones in August. Sick leaves need to be removed regularly. In summer, to fight the solution is applied directly under the bushes or on the foliage. Do it in the early morning or late evening. Fallen leaves are constantly burned immediately after collection. Some varieties have good resistance to black spot roses. However, they are also treated for the disease, even if there are no symptoms.
Prevention of black spot on roses
The disease is easier to prevent than to notice black spot on the leaves and shoots of a rose in a timely manner and start fighting it.
It is real to prevent the development of black spot on rose leaves. The main thing is to carefully adhere to basic protection measures. You can use both folk measures and chemicals.
In the spring
As a preventive measure, one of the most important is spring spraying. Before bud break, a 2-4% solution of Bordeaux mixture is used. The following year, copper sulfate is used. Medicines like Hom or Zircon are also suitable. Alternation is necessary so that the dispute does not get used.
The second time chemicals from the disease are used at the beginning of leaf blooming. Copper-containing mixtures are used for black spotting of roses on flowers and leaves.
Lettom
As a prevention of the disease in the summer, you should regularly clean the entire soil next to weeds. Weed removal should be regular. Fertilize and constantly inspect the leaves. If their color has changed to yellow, blotches of a rounded shape have appeared, then full-fledged therapy is needed. From June to September, to eliminate black spot in roses, growth activators are used. They will help improve the protective functions.
In the autumn
To prevent black spotting on roses, potassium-phosphorus supplements should be applied every autumn. To exclude the appearance of the disease next year, you should cut off all the leaf plates on the rose. As a care, they are immediately burned.
After the rose is trimmed, you need to use copper-containing compounds. This will eliminate spotting in the plant after warming.
Before the cold, as a care, the rose must be covered to protect it from frost.
Useful Tips
To eliminate black spot in different varieties of roses, you need to follow simple recommendations. Experienced gardeners recommend:
- Choose areas where the wild rose is located as far as possible. It increases the risk of pathology.
- Plant varieties of roses that are less susceptible to black spot. They can also get sick, but the risk of pathology in such roses is much lower. Such varieties are able to resist the disease.
- Do not plant roses close to other plants and other roses, regardless of variety. The thickening of the flower bed accelerates infection. Between plantings, the recommended distance must be maintained.
- Remove weeds promptly. Weeds hinder air circulation. Roses are deteriorating immunity.
- Avoid planting roses in a lowland or with a high occurrence of groundwater.
- Carry out the correct feeding of the plant.
- Conduct ongoing site maintenance. It is necessary to burn garbage in the form of dry foliage and grass in a timely manner.
It is not difficult to prevent the appearance of black spot. The main thing is to create favorable conditions for plant growth and, if possible, choose resistant species.