Getting a rich harvest is the desire of every vegetable grower, but, unfortunately, not everything depends on the efforts made. It happens that preventive measures are taken, but the plants still get sick. One of the most common diseases of nightshades grown in closed areas is brown olive blotch, or cladosporiosis.
From the article you will learn what kind of disease this is - cladosporiosis of tomatoes in a greenhouse, how to treat it and how to protect the crop from death. The material contains advice from experienced summer residents and photos of the manifestation of the disease on plants.
What kind of disease is this
Cladosporiosis is often called brown spot. The disease is a fungal disease and can infect plants en masse. Due to the disease, there is a risk of losing 50% of the harvest. Cladosporiosis often affects seedlings grown in a greenhouse or greenhouse.
The disease is almost impossible to remove, since its causative agent is able to maintain its vital activity for 10 months, even in unfavorable weather conditions. It can overwinter in the ground and infect seedlings again in the new season. The fungus spreads in the form of dust with spores - it can be brought by the wind from a neighboring area. One of the conditions for the spread of the disease is high humidity.
How does it affect tomatoes?
One infected bush can cause the death of the entire seedling. The symptoms of cladosporiosis cannot be confused with another disease: brown spots and a gray coating form on the leaves, then they begin to turn yellow and fall off. The stem and fruits remain intact, but the plants begin to suffer, having lost their green mass.
The tomatoes do not ripen and begin to rot and wrinkle. Large tomatoes may develop raised brown spots. At the first symptoms of the disease, begin treatment immediately.
Symptoms and external signs
Cladosporiosis develops gradually; the disease can be recognized during flowering and fruit formation. Already in July, you can see characteristic light spots on the leaves; a change in their color to brown indicates the beginning of the process of withering of the plant.
If treatment is not started, the surface of the leaf thickens and becomes velvety to the touch. Then the green mass of the plant falls off, which affects the process of fruit formation.
Description of the stages of disease development:
- Initial - symptoms appear during flowering. Light green spots appear on the outside of the leaf, and a light gray coating forms on the inside.
- Progressive - the upper leaves are affected, but the stem and fruits remain intact. The surface of the leaf becomes denser, becomes velvety, and the green mass of the plant loses its shape and color. The spots on the leaves darken and become brown; their more intense color is observed on the inner surface of the leaf.
- Active - leaves fall, the plant withers, the fungus attacks the fruits. No method can save seedlings.
What preventive measures will help avoid the occurrence and development of cladosporiosis?
The formation of brown marks on tomato leaves can be prevented. There are several effective preventative measures.
Seed disinfection
There are frequent cases of fungal infection being introduced into a greenhouse with infected seedling material. To prevent this, it is necessary to treat the seeds before sowing in disinfectants:
- in a light pink (1%) solution of potassium permanganate - soak for half an hour;
- in a heated solution (+40...+45 °C) of hydrogen peroxide (3%) - 7-10 minutes;
- in a fungicide diluted according to instructions (Trichodermin, Fitosporin, Rizoplan, etc.).
Disinfection of tomato seeds
Hydrothermal treatment shows good results. The seeds wrapped in a cloth are immersed in hot water (+48...+50 °C) for 20 minutes, then they are cooled, washed in cold water for 3-4 minutes. Some of the grains will die, but the remaining ones will be healthy and viable.
Soil treatment
Simultaneously with spraying the above-ground vegetative mass of tomatoes with antifungal drugs, it is necessary to treat the soil under the bushes. After all, a huge number of spores get there, which, when the opportunity arises, inevitably become more active. If there are still plants in the greenhouse, it is better to use biofungicidal agents.
At the end of the summer season, when the entire harvest has been harvested, the land will need to be processed more radically:
- Bordeaux mixture (2-3%);
- copper sulfate (up to 4%);
- one of the chemical fungicides.
You can also treat the soil from the cladosporiosis fungus with ordinary boiling water, pouring it generously over the beds. It is recommended to do this twice: late autumn and spring, about two weeks before planting tomato seedlings.
Selecting a tomato variety that is resistant to the disease
Brown spots on tomato leaves caused by cladosporiosis may not appear at all if you select varieties that have good resistance to this disease.
According to the experience of many summer residents, confirmed by numerous reviews, tomatoes that are not genetically prone to cladosporiosis include:
- "Spartacus";
- "Charisma";
- "Opera";
- "Pink Paradise";
- "Doll Masha";
- "Marissa"
- "Delicacy";
- "Bohemia";
- "Vezha";
- "Martin";
- "Giant";
- "Funtik";
- "Business lady";
- "Pink Magic";
- "Evpator" and others.
A thoughtful choice of planting material is especially important if an infection was detected in the previous season. Before purchasing, it is recommended to carefully study the varietal descriptions of tomatoes.
Causes of infection
Cladosporiosis most often affects plants grown in unheated greenhouses or greenhouses. The first symptoms appear in the second half of summer, in the southern regions - already in the spring.
The causative agent of the disease
The causative agent of cladosporiosis is the fungus Cladosporium fulvum Cooke. It is distinguished by its durability: it can withstand both cold and heat for 10 months. Infection occurs when the mycelium of the microorganism enters the plant. The pathogen is constantly evolving, adapting to drugs.
The fungus gets on the plants and begins to germinate. The manifestation of its vital activity can be seen in the middle of the growing season. Weakened leaves are the first to be affected.
Important! In addition to leaves, the fungus attacks flowers and young ovaries.
Terms of distribution
The fungus reproduces by conidia (spores), which, due to their lightness, are carried by the wind. The source of infection can also be ordinary objects on which the pathogen came into contact: gardening tools, shoes, water for irrigation.
Peculiarity. The disease is not typical for seedlings grown in open ground.
Fungal spores become active at elevated humidity levels, which is not uncommon in greenhouses. Another factor stimulating the active phase is temperature changes. The optimal indicator for the life of the fungus is +22...+25C with a humidity of 80%. If the humidity drops to 70%, the proliferation of microorganisms stops.
How and with what to treat
Treatment of cladosporiosis directly depends on the degree of spread of the disease. If you start fighting the disease immediately after identifying light spots, the chances of success are high. If you ignore the disease, there is a chance of losing the entire harvest.
There are two ways to fight diseases: folk remedies and chemistry. For effective treatment, an integrated approach is used. At the first stage, you can tear off the affected leaves and treat with products; when brown spots appear, the plant is unlikely to be helped by anything; it is removed from the garden along with the roots.
Chemicals
Chemicals effectively combat the causative agent of cladosporiosis; they are used even when plants are severely damaged by the disease. Before use, carefully read the instructions and do not violate the manufacturers' recommendations.
It is best to carry out processing in the evening; it is important that there is no rain or strong wind during this period. You can repeat the procedure after two weeks.
Important! Apply chemicals at least a month before harvest.
Broad-spectrum fungicides are suitable for treating brown spot:
- "HOM";
- "Bravo";
- "Polyram";
- "Abiga Peak";
- "Ditan NeoTek 75";
- copper oxychloride.
Traditional methods
The methods used by people are effective only at the beginning of the disease; it will not be possible to cure plants from brown olive spot at an advanced stage.
The following remedies help neutralize the fungus best:
- whey - pour 1 liter of whey into a bucket of water, the solution is suitable for spraying;
- infusion of garlic and iodine - for 1 bucket of water you will need 30 drops of iodine, 1 clove of garlic or 500 g of arrows;
- iodine chloride - the product is suitable for pre-planting treatment of soil and seedlings. 30 g of potassium chloride and 40 drops of iodine are dissolved in a bucket of water. When disinfecting the soil, the solution should reach a depth of 10 cm;
- milk solution with iodine - you will need 0.5 liters of milk, 5 liters of water and 15 drops of iodine;
- wood ash decoction - boil 300 g of ash in 10 liters of water for 25 minutes, then leave to steep for two days;
- manganese solution;
- 1% solution of Bordeaux mixture;
- colloidal sulfur solution - 3 tbsp. dry matter is mixed with 1 tbsp. copper sulfate and 3 tbsp. polycarbacin. The concentrate is diluted in 10 liters of water and 2 tablespoons are added. liquid soap;
- yeast - for spraying use a solution prepared from a dry or wet product.
Attention! For greater effectiveness, you can add liquid soap to the finished solution. Soapy water protects against pests and promotes plant health.
Agrotechnical techniques
At the first signs of disease, you should check the density of the beds. If during planting in the ground the plants were planted in a heap, it is worth thinning out the area so that air can circulate freely between the bushes. The distance between low-growing tomatoes should be 40-50 cm, the beds should be no closer than 50-70 cm.
Effective protection against nightshade diseases is compliance with the rules of crop rotation. You cannot plant tomatoes in the same area year after year. The causative agent of cladosporiosis can remain in the soil for up to a year and infect new seedlings. It is recommended to plant tomatoes in the same beds only after 3-4 years.
Tillage after cladosporiosis
After destroying the causative agent of brown spot on tomatoes, you need to disinfect the soil in the greenhouse or greenhouse. If the plants are still in the growing season, the best option is to use biological agents.
After harvesting the last harvest and removing bushes from the beds, the land can be processed more thoroughly.
In addition to biological products and regular boiling water, the following are used to disinfect soil:
- 3% solution of Bordeaux mixture;
- copper oxychloride not higher than 4%;
- Oxychom according to the instructions.
Since cladosporiosis or brown spot is resistant to frost and can become active after 10 months spent in unfavorable conditions, the soil sterilization procedure should be repeated in the spring, before preparing the site for planting tomatoes.
Preventive measures
It is better to prevent the onset of a disease than to try to cure it later. In the case of brown olive spot, the most effective measure is to maintain conditions in the greenhouse that are unfavorable for the fungus.
Prevention:
- maintain optimal humidity, temperature and lighting;
- remove plant residues and debris after harvesting;
- regularly treat the greenhouse frame with disinfectants;
- carry out pre-planting soil treatment;
- observe crop rotation;
- choose varieties for planting that are resistant to the disease;
- When planting seedlings, maintain a distance between the bushes;
- do not flood the plants;
- mulch the soil with sawdust, chopped grass and plastic film;
- Regularly ventilate the room or install a ventilation system.
Chemical methods for treating tomatoes
In case of severe damage, the use of chemicals cannot be avoided. Agronomists recommend Bravo, Khom, Polykhom, Tsineb, Kaptan.
Before use, you must carefully read the instructions and protect yourself with protective equipment during the treatment.
Advice from gardeners
Tomato resistance to the disease is the main factor of protection against brown spot. Breeders are constantly developing new crop hybrids, which are not only characterized by high yields, but also by the percentage of survival.
These varieties and hybrids include:
- Delicacy;
- Giant;
- Vezha;
- Pink Paradise F1;
- Pink Magic F1;
- Our Masha F1;
- Vitador F1;
- Space Star F1;
- Swallow F1;
- Funtik;
- Pinky F1;
- Evpator;
- Business Lady F1.
To prevent cladosporiosis, the following drugs are used: Fitosporin-M, Pseudobacterin-2, Integral, Gamair and Alirin-B. After the first treatment, the procedure is repeated after 20 days.
You can increase the resistance of tomatoes to cladosporiosis by treating the plants with an infusion of herbs: nettle and dandelion. The plants are crushed and garlic slices are added to them, after which the ingredients are poured with water and left for two days.
Experienced summer residents have noticed that the fungus is killed by the following pharmaceutical drugs: Trichopolum, Metronidazole and Furacilin.
Rules for using drugs:
- At the beginning of the season, treat the seedlings with Metronidazole - dissolve 13-15 tablets of the drug in 1 liter of water. You need to thoroughly wipe all the tomato leaves with the solution.
- "Trichopol" is suitable for regular preventive treatment. The procedure is carried out every 10-14 days - 1 tablet of the drug is dissolved in 1 liter of water. The product not only kills fungal spores, but also protects tomatoes from re-infection.
- Tomatoes are treated with Furacilin three times during the entire growing season - 1 tablet of the drug is dissolved in 1 liter of water.
