Black spot is one of the diseases that affects plants. There are different causative agents of this disease. For example, Marssonina rosae is a fungus that infects roses. It is he who is the cause of the appearance of black spots on the foliage. Another pathogen is called Syringae. It can be observed when the lilac is defeated.
Features of black spot
It is very important to detect black spot damage to the plant in time. This will eliminate the disease in a shorter time and without side effects for the culture itself. Therefore, as a preventive measure, it is necessary to systematically conduct a careful examination of all parts of the plant.
With a disease with black spot, characteristic specks of brown, almost black color appear (which is why the disease received this name). These spots may have a lighter center or edges. There are swollen specks that are either oval or round in shape.
A favorable time for the onset of the disease is the beginning of the summer period, so you need to make it a rule to carefully examine the plants at this particular time. The disease can develop at absolutely different rates. For example, with a rapid course of the disease, extensive foliage lesions are observed. It quickly turns yellow and falls off, and the branches become bare. The shrub is noticeably weakening, its decorative effect is lost, there is almost no flowering, and fruitful crops bring a very meager harvest.
An appropriate environment must be created for the infection to spread. High humidity, wind, and the presence of pests contribute to the rapid progression of the disease. This is especially noticeable during a long period of rains, when the air temperature is low. Potassium deficiency contributes to the spread of the fungus.
The beginning for the development of the disease can be a simple mechanical damage to either foliage or bark.
Black spot treatment
Before choosing a method for treating black spot, it is necessary to establish an accurate diagnosis, that is, to confirm the presence of this particular disease. There are two forms of the disease: caused by a fungus, as in the case of pink, and caused by bacteria, on tomatoes and peppers.
Unified methods have been created to combat black spot of any origin. The first thing to do is to take measures to strengthen the immunity of the diseased plant. This will stop the further development of the disease, and in the future, reverse it. There are preventive measures to improve the health of any culture.
Preventive actions
The first and foremost preventive measure for any crop is sowing seedlings in the right place. This requires a detailed study of the conditions that the plant requires for normal development. For example, shade-loving plants are planted in shaded areas.If there are none, it is necessary to create artificial shading. And for sun-loving crops, open lighted areas are chosen. The reaction of the plant to drafts, winds, temperature changes is also taken into account. Failure to comply with these initial conditions weakens the culture. It becomes more susceptible to pests and diseases.
The second thing to consider is the quality of the soil. It must meet all the requirements of the plant. There are more whimsical cultures, there are less. Information on soil requirements can be easily found on the Internet. Don't be lazy. The soil is very, very important. The plant will develop normally only in the correct soil suitable for it.
On a note! Experts recommend choosing varieties with increased resistance to diseases and pests, as well as taking into account local climatic conditions. There are zoned varieties and hybrids, that is, intended for cultivation in a specific area. For example, for the Urals, Siberia, the Central strip.
Another preventive measure is the preparation of seeds before sowing. Seeds must be disinfected unless otherwise indicated on the packaging. The disembarkation is carried out within the specified time frame and according to the presented scheme.
It is important to properly care for the plants, including watering on time, and applying fertilizers to the soil. After harvesting, it is imperative to cleanse the site of vegetation remnants and put the soil in order.
Black spot on garden crops
As mentioned above, black spot can appear on different crops.
Black spot of tomatoes
Xanthomonas vesicatoria is a stick-shaped gram-negative bacterium that can infect both greenhouse tomatoes and those grown in garden beds. Seedlings and young bushes have watery spots on the foliage. At first, they look more like dots, and over time they increase to 1-2 mm. The edge turns yellow as it grows.
On adult shrubs, spots appear on petioles, shoots, leaves, and also fruits. On the latter, dark spots have a watery edging. Over time, growing to 0.8 cm, they turn into sores. For a long time, the pathogen can be on plant debris, seed. Before sowing, it is imperative to disinfect the seeds.
When parts of the plant located above the ground are damaged, the pathogen penetrates through cracks, damage. After that, it quickly spreads through the tissues. The first symptoms appear already on the 3rd - 5th day after infection.
On fruits, spotting appears a little later. And two weeks later, neighboring plantings are infected. The favorable temperature for the development of the disease is from 25 degrees and above. Deceleration occurs at lower temperatures.
Also, a favorable condition for the development of fungi or bacteria is high humidity up to 70-75% with moisture ingress on the ground parts of the plant.
After collecting the fruits, the site is carefully cleaned. This is necessary to eliminate the source from which the pathogen is powered. After 4-5 weeks, there will be no trace of fungi and bacteria. Breeders have not yet developed varieties and hybrids of tomatoes that are resistant to black spot. However, gardeners have noticed that those tomatoes that have good immunity to the fungus are less likely to get sick with black spot. Therefore, it is necessary to carry out all preventive measures.
As already mentioned, preventive training is very important in the fight against infectious diseases. In particular, the correct processing of the seedbed. To do this, carry out the procedure for dressing tomato seeds. There are several ways to disinfect:
- Prepare a solution based on a fungicide and fill it with seeds. Duration of soaking is 1 hour.
- Treatment in a solution of potassium permanganate for half an hour.
- A solution is made from ternary sodium phosphate at the rate of 12 g per 100 ml of water. The seeds are kept in the prepared solution for an hour, after which the planting material is thoroughly washed under running water. You can put the seeds in a sieve and rinse in this way for 20-30 minutes.
- The seeds are soaked in hot water (about 60 degrees) for about 20 minutes.
These simple and reliable methods will help prevent blackleg infestation and remove bacteria and fungi from seeds, if present.
In case of internal seed infection, another method is used using the biological fungicide "Planriz" (1%). The treatment solution is prepared in accordance with the instructions and the seeds are immersed in it. Before planting in the soil, seedlings are treated twice with the following solutions to choose from:
- Fitosporin-M;
- Baktofit;
- Gamair;
- Planriz.
Fitolavin is especially effective.
Some time after planting tomatoes in the ground, it is imperative that a preventive spraying is carried out with a solution of a product that contains copper. For this purpose, Hom, Oxyhom, 1% Bordeaux mixture and other means that have a similar mechanism of action are perfect.
Black pepper spot
Sweet peppers and tomatoes have the same pathogen (Xanthomonas vesicatoria). It affects most often those parts of the bushes that are not yet sufficiently strong. It appears on petioles, foliage, fruits and shoots in the form of black specks. First, these spots are round, and then oblong. The original length is 1–2 mm. On closer inspection, you can see a border of a light yellow tint on the spots. They are located along all the veins on the leaves. In the center of the spots, necrosis is formed, which is surrounded by a watery dark border. As the lesion develops, the spots grow up to 6-8 mm in length. And from ordinary specks, they become rotting sores. Preventive measures are exactly the same as for tomatoes.
Black spot on fruit and berry crops
Fruit and berry crops can also get sick with black spot, including grapes.
Black spot on grapes
Black spot of grapes has many alternative names: phomopsis, cracking of the bark, dry hands, ecoriosis, dying off of shoots. These are all names for the same ailment. The causative agent is the fungus Phomopsis viticola. The initial signs of the disease may appear in June on the nodes of annual shoots. The affected berries develop oval or round dark brown specks. They look bloated and watery. In the center of the spot is a necrotic focus.
Over time, their number is growing. The dots connect to each other to form larger spots. An autopsy takes place in the center of such neoplasms. And the cork fabric around the edges looks like scabs. In most cases, only the first 6 or 7 internodes are infested with mottling. Also, spotting occurs on the leaves located in the lower part of plants, cluster ridges, antennae, flowers.
Leaf necrosis has a light border. The leaves are curly due to the stretched fabrics. And in some places, gaps appear, which form holes. The foliage begins to turn yellow ahead of time, the leaves wilt and fall off.
Due to the deformation of the foliage and the formation of holes on it, the process of photosynthesis becomes weaker. It can also happen that many buds die in the lower internodes of the stems at the age of one year. Affected grapes turn a dark purple color. There is a deterioration in taste, the bark acquires a grayish-white color.
Favorable factors for the spread of black spot are high humidity, wind, rain, pests. The diseased plant is less frost-resistant. As a rule, death occurs after 5 or 6 years.As with other crops, experts advise giving preference to those varieties that have good immunity. Among such varieties are Cabernet Sauvignon, Liana, Traminer, Tavrida, Iskra, Riesling, Bastardo Magarachsky and Relay.
When the first signs of black spot are detected, it is necessary to immediately begin treatment of the grapes. A characteristic feature of this disease is the deep location of the fungal mycelium in plant tissues. For this reason, fungicidal treatments will not be highly effective.
It is recommended to use Nitrafen or DNOC for processing. These remedies eliminate fungal spores and fruiting bodies. Once again, it is worth recalling that timely processing is very important. And the best thing is to do prevention. It is the most reliable protection against black spot, which will save the grower's time and energy and, of course, the harvest.
During the growing season, it is useful to treat as a preventive measure with the following means:
- Mikal;
- Efal;
- 1% bordeaux liquid;
- Eupren.
The first processing of grapes is carried out immediately after swelling of the buds at the very beginning of spring. The next spraying is carried out after the appearance of four to five full-fledged leaves on the stems. The third time is processed after flowering. It is preferable to choose an agent with a complex focus, that is, one that will be effective against spotting, and peronosporosis, and powdery mildew.
When the culture is severely affected, spray with a solution with copper in the composition. Spraying time is after leaf fall or after pruning. The greatest effectiveness against black spot was shown by such fungicides as Triadimenol, Maxim, Kaptan, Mancozeb.
By choosing one of the above drugs, you can be sure of the effectiveness of the treatment.
Grapes require preventive spraying to avoid getting black spot. Below are the main preventive measures:
- plant exceptionally healthy seeds;
- regularly inspect plantings for signs of black spot;
- when the first symptoms are detected, the affected parts are trimmed and burned;
- the stems should not lie on the ground, so they are tied up;
- make balanced correct feeding (boron and zinc are essential trace elements in the composition).
It is impossible to immediately eliminate black spot from grapes. Therefore, you should be patient and prepare in advance for a long struggle. After the final elimination of the disease, it is necessary to continue preventive treatments in the same mode, with the same regularity.
Black spot on flowers
Black spot on roses
Marssonina rosae - the causative agent of black spot on roses - affects both the stem and foliage. White-red spots appear on the outside of the leaf plate, which then turn black. They are round and look like they have a radiant border. First of all, the foliage is affected in the lower part, and then the infection spreads throughout the bush.
Affected leaves change from rich green to dark brown. Then twisting, drying and dying off occurs. The bush becomes weaker and weaker, decorativeness disappears. There are fewer buds or no buds are formed at all. With a high degree of damage, by the beginning of the autumn period, the foliage completely flies.
When the first symptoms of a rose disease are detected, it is necessary to cut off the damaged leaf plates and remove the fallen leaves. They begin to spray with a solution systematically at intervals of a week. To prepare it, you can take one of the following means:
- Abig Peak;
- Topaz;
- Coming soon;
- Thiophanate methyl;
- Previkur;
- Fundazol;
- Trifloxystrobin;
- bordeaux liquid.
The soil around the rose is spilled several times (preferably three times) with Fitosporin-M diluted in water.
In the fall, they begin to prepare the rose for wintering: they remove the foliage, collect those leaves that have flown around and wilted. It is preferable to burn it all.
The remaining bush is treated with 3% iron sulfate diluted with water. In the spring, before the growing season, all branches and stems are cut, down to healthy wood. Spraying of the bush itself and the soil around is carried out. The fungicides listed above are suitable.
Signs of black spot on a rose are similar to diseases such as brown and purple spot, phyllosticosis, sphacelloma, ascochitosis, septoria. It is very easy to confuse these diseases. However, there is no need to worry, because the drugs mentioned above are suitable for the treatment of all the listed diseases.
Preparations for black spot (fungicides)
Before starting the treatment of black spot, you should carefully read the instructions for the fungicide, its action, what it is used for, in what quantities. Next, a list of fungicides that are most often used to eliminate black spot will be presented, as well as a brief description of each of them. These fungicides are also used for fungal infections.
- Abiga Peak - is a contact fungicide. Its range of applications is very wide. The composition contains copper, thanks to which it successfully fights against fungus and bacteria. Suitable for the treatment of black legs of any origin.
- Baktofit - a popular biological fungicide, equally successfully used to eliminate fungal and bacterial diseases.
- Bordeaux liquid - one of the most commonly used agents in the prevention and treatment of diseases caused by the fungus. Has a wide range of applications. Berry, melons and vegetables are processed with it.
- Gamair - completely biological bactericide. Its range of applications is more modest. It is used to suppress the activity of certain types of bacteria and fungi, both in soil and on plants.
- Captan - has a "fungal" specialization and multidirectional mechanism of action.
- Maksim - contact fungicide, often used at the stage of pre-sowing treatment. With its help, seeds are treated. Good prevention.
- Mancozeb - contact drug, perfectly suitable as a prophylactic agent against fungus.
- Nitrafen - a complex fungicide that has a good effect due to the combination of several properties in it at once: bactericidal, insecticidal and fungicidal. This combination allows it to be used in many cultures.
- Oxyhom Is a good systemic contact fungicide. He has a very broad spectrum of action. Used for fungal infections.
- Planriz - a microbiological protective agent capable of protecting various crops from a variety of diseases. It is not only an excellent fungicide. Planriz has bactericidal and insecticidal properties. It is a reliable protection against fungi, bacteria, insect pests.
- Previkur - a fungicidal preparation of systemic action, aimed at protecting plants. As an additional effect, it has a stimulating effect.
- Speed - a systemic fungicide that provides long-term protection against diseases caused by the fungus. It can also be used when the culture is sick. Possesses medicinal properties.
- Thiophanate methyl - systemic contact fungicide, pesticide and insecticide. Good for preventive treatments.
- Topaz - It is used to eliminate a whole range of diseases caused by the fungus.
- Triadimenol - has shown high efficiency in eliminating a huge number of diseases. It can be applied during the growing season.
- Trifloxystrobin - a systemic contact fungicide has shown excellent prophylactic and therapeutic effect. It is used to treat a huge range of diseases, including black spot.
- Fitolavin - biological bactericide of systemic action.It is used as a protection and treatment for diseases of fungal and bacterial origin.
- Fitosporin-M - contact biological fungicide of prophylactic orientation. It is effective against many types of bacteria and fungi.
- Fundazol - systemic fungicide and dressing agent. Has a broad spectrum of action. Effectively fights all sorts of fungal diseases.
- Hom - a fairly well-known drug of systemic local action. It is used in the treatment of many diseases of cultures.
- Euparen - a drug of contact action. It has a pronounced preventive effect ..
- Efal - a systemic agent for the prevention of diseases. Effective for fruit and vegetable crops. The list of diseases for which it has shown its effectiveness is very extensive.
Folk remedies
Despite the presence of a large number of a wide variety of fungicides, folk remedies do not stand aside. Of course, they are not so effective in terms of therapy when the plant is already sick. But they are well suited as a preventive measure. Below are some recipes.
- To prepare the solution, you only need iodine and water. Take 1 mg of iodine and dissolve in 2 tbsp. l. water. Spraying is carried out.
- This recipe is for treating roses. Mix the mullein with water in a ratio of 1:10. The resulting mixture is insisted for several days in a row. At the onset of spring, after removing the shelter from the rose, pour over it with the resulting infusion. Several more procedures (two or three) are carried out from May to July.
- Take garlic or onion peels in the amount of 30-40 grams, boil. Next, the broth is infused for 6-8 hours, after which it is filtered. The resulting product is used for spraying rose bushes, as well as for cultivating the soil under them. When there are flowers on the bush, they no longer spray it, but pour the broth at the very root. Spraying can lead to discoloration of the petals.
There are a large number of gardeners' reviews where they do not recommend using citrus and herbal infusions (for example, from nettle), because they are ineffective against black spot.
So, black spot is a plant disease that is caused by various kinds of pathogens. It can be either bacteria or fungi. Black spot can often be observed on roses, tomatoes, and peppers. The disease also appears on berry, fruit, vegetable, melon crops. Favorable conditions for the development of the disease are high humidity, low temperatures.
A characteristic sign of black spot is the appearance of spots on the plantings. It is necessary to carry out preventive examinations of plants and, when the first symptoms are detected, immediately begin treatment. There are many fungicides that can be used to combat black spot. There are also non-traditional folk methods for processing plants. They are suitable as preventive measures.
