Common Tomato Diseases
Tomatoes, or tomatoes, are a favorite vegetable in all parts of the world. Under optimal conditions, these amazing plants are able to bear fruit all year round, supplying people with delicious high-energy, dietary fruits (berries) containing a large list of vitamins, trace elements, organic acids and other compounds necessary for humans. Like all plants, tomatoes are susceptible to diseases that alter the taste and quality of fruits so much that they cannot be used as food. Tomato diseases are associated mainly with non-compliance with the requirements for agrotechnical methods of cultivation.
Types of Tomato Diseases
According to the effect on plants, tomato diseases can be divided into 2 groups:
Noncommunicable diseases of tomatoes are local in nature. They are not transmitted to other plants, and when correcting deficiencies in agricultural care, they recover without infecting neighboring plants. Agrotechnical violations may be related to:
- with insufficient or abundant watering,
- unbalanced top dressing,
- violation of air humidity, lighting, temperature and other factors.
Infectious diseases of tomatoes, with some external similarity with non-infectious diseases, are distinguished by focal, rapidly spreading damage to a large number of plants. To determine the type of infection of the culture, with optimal agricultural technology, it is necessary to test the external signs of the disease that has manifested.
Please note, if the disease is not correctly identified, plant protection products may not work, especially biological ones.
External manifestations of non-infectious lesions of tomatoes
Lack of moisture
The plant loses turgor. The leaves of the tomato hang and, together with the young stems, become dull green. They may wrinkle and turn yellow. Tomatoes dump flowers and small fruits. Reanimate plants gradually. At first, by small watering under a bush and only after 1-3 days - by the full norm of the settled warm water.
Weak spots appear at the root neck of plants, spreading down the stem, they cause rotting of the roots of the tomato. At the same time, the leaves of the aerial parts of the tomato grow dull and fall off. Cracking of fruits is observed.
It is necessary to stop watering, dry the bed with plants with dry sand or horse peat, other moisture-absorbing material.
Remember! Do not water tomatoes with a strong jet of cold water. Reception causes cracking of the fruit and with the ingestion of infection, an infectious disease of the culture begins.
Unbalanced Tomato Nutrition
Frequent top dressing of a tomato with high fertilizer standards, especially nitrogen, causes increased growth of vegetative organs to the detriment of crop formation. When making complex dressings, overfeeding with nitrogen is unacceptable. Elevated doses of nitrogen contribute to fruit cracking and secondary infection with infectious diseases.
In hot, dry weather, plants can get a sunburn, which is manifested by whitish spots on the fruits. Tomato fruits stop developing, become tuberous, dense, tasteless.
If the region is characterized by long hot periods, it is necessary to provide methods for shading plants with any material that prevents direct sunlight from entering the crop (light canopy from film, spunbond, etc.).
Common infectious diseases of tomatoes
If, after bringing the cultivation of tomato cultivation into norm, the signs of the disease remain, then the plants are affected by infectious diseases, which are conditionally divided into 3 groups:
- viral, mycoplasmal.
Plant infection can be primary or secondary, which begins indirectly through non-infectious plant damage.
Fungal infectious diseases of tomatoes
Fungal diseases are caused by a group of pathogenic fungi. The pathogenic microflora, once in suitable conditions, begins to grow and develop intensively, affecting nearby plants. For 1-3 days, the mycelium can completely destroy the tomato crop. The fungal harmfulness is enhanced by the fact that at the same time it can affect the whole plant, including the root system.
The most harmful fungal diseases of tomatoes include:
- late blight,
- Fusarium wilt,
- root, basal and fruit rot.
The main sources of infection are planting material (untreated seeds, diseased seedlings) and soil.
Late blight of tomatoes
The disease with an epiphytotic lesion in 2-3 days can completely destroy the tomato crop regardless of the growing conditions (open ground, greenhouses, greenhouses). Late blight is also called brown rot. It appears first on the leaves of the lower tier. Browning of certain sections of the lower side of the leaf blade is observed, which gradually merge into one spot. On the browned areas, the pathogen mycelium appears in the form of powdery plaque, which eventually grows on the upper part of the leaf blade.
Tomato leaves dry out, turn yellow and curl, necrosis of leaf tissue begins. Petioles and stems are covered with oblong dark spots that turn into necrotic formations. The disease passes to inflorescences and ovary, which gradually darken and dry out. The tissues of the fruits coarsen, inside they acquire a brown-brown color and rot. Seeds and fruits become unusable.
Do not confuse late blight of tomatoes with powdery mildew. With powdery mildew, there are no brown spots of necrosing tissue.
Infection usually begins in wet, cold (in the morning) weather (early August) or with an excess of humidity with temperature changes. The pathogen overwinters on plant tops or in the soil. In the spring of spores, the remains of the mycelium are carried by wind, water.
Medicinal measures against late blight
Blight is considered a potato fungus. Therefore, never in culture circulation need to plant these crops nearby or use potatoes as a predecessor of tomatoes.
Spraying with Bordeaux liquid 2 weeks after planting tomato seedlings or during the formation of 2 to 3 true leaves in seedling-free crops. Spraying is also carried out at the first manifestations of the disease.
For plant treatments, you can use chemicals: tattoo, infinito, acrobat, ridomil gold, metaxil and others. 1 - 2 sprayings are enough to kill the disease. But chemicals can be used at least 30 days before harvesting. In households, chemicals are unacceptable.
To obtain an environmentally friendly crop, it is better to use biofungicides: mycosan, bactofit, trichodermin, coniotirin, ampelomycin, etc. These biological products can be used throughout the growing season until the harvest of tomatoes. They do not harm human health. In order not to cause plant addiction to the drug, it is better to alternate the used biological products or prepare tank mixtures. Each preparation is accompanied by a memo or recommendations, which indicate the time, methods, optimal temperature conditions, doses and phases of treatment of plants and soil.
Fusarium wilting of tomatoes
Fusarium wilting is caused by soil fungi that affect the root system of plants. The primary manifestation of the disease is similar to insufficient supply of plants with moisture. Plants wilt, and then the stems below become dark brown to black and crack.
The disease passes to the aboveground mass, affecting first the lower leaves of tomatoes. They become pale green, yellowish, the venation of the leaf blade is clarified. Gradually, mushroom hyphae rise up along deformed petioles and stems, capturing all healthy parts of tomatoes. During this period, a pinkish coating appears on the root neck of diseased plants. The most typical fusarium wilt manifests itself during the flowering of tomatoes and the formation of fruits.
Remember! A distinctive sign of Fusarium infection is a pink coating on the root of the plant neck.
The soil pathogen hibernates in diseased tops and fruits. Actively develops with high humidity and sudden changes in temperature. The infection penetrates during irrigation, through contaminated soil, dirty tools.
Treatment measures against Fusarium wilting of tomatoes
As with late blight of tomatoes, it is necessary to strictly observe agrotechnical requirements, especially those related to watering and top dressing. Of the chemicals, you can use the same as in the defeat of late blight. Since the disease most often affects already adult plants, chemicals should be excluded from the list of protective measures or used only in the early stages. It is better to spray tomatoes with copper-containing preparations (blue vitriol or Bordeaux liquid). Of the biological products, trichodermin, phytosporin-M, is most active against fusarium.
Measures against late blight and fusariosis, and other fungal diseases include cultivation, disinfection of seed and seedlings with phytosporin-M working solutions. Shed the soil 1–2 weeks before planting / sowing with phytosporin-M, trichodermin, planriz, bactofit, trichoflor, alirin-B, gamair and others. Dig the soil 15-20 cm. Before planting, add a solution of biofungicide or 1-2 tablets of glyocladine into the centimeter layer in each well. Treat the plants during the growing season with the same solutions according to the recommendations indicated on each package.
Rot of tomatoes. Root and root rot
Root and root rot of tomatoes are caused by several groups of fungal pathogens. The main source of infection is soil, humus piles, non-sterile substrate in greenhouses. The rapid spread of disease is associated with excessive watering. The root system and the area of the root neck are affected. In violation of agrotechnical requirements, the disease begins with seedlings and continues throughout the growing season.
The main symptoms of root and basal rot:
- focal wilting of plants, especially with waterlogging,
- discoloration and consistency of tissues of the root system and in the zone of the root neck.
In seedlings of tomatoes, a thin constriction appears under the cotyledon leaves, and in older seedlings, under the first pair of real leaves. The amazing effect of rot is manifested in the form of blackening of the root and root zone (black leg), thinning and rot (rhizoctonia, or white leg). Tomato root growth is limited by a central shoot without lateral and fibrous roots. The root is easily pulled out of the soil. The stems in the root zone acquire a brown color and a soaked texture. On the cross section of the tomato stem, the brown-red rings of the diseased conductive vessels are visible.
A distinctive feature of root rot is a constriction in the zone of the root neck, a change in the natural color of the root. The root is one rod without lateral roots; the root neck has a cobwebby or whitish felt coating.
Rotted fruits of tomatoes. Vertex rot of tomatoes, or alternariosis
Some groups of rot cause rotting of the root and stem at the same time, affect the leaves, pass to the fruits. Rotting lesions are not always a sign of plant infection. So, the primary defeat of the top rot of tomatoes is a non-infectious disease. Its appearance is associated with extreme environmental conditions (a combination of low humidity at high temperature), violation of agrotechnical requirements (excess nitrogen) and is accompanied by the destruction of the tissues of tomato fruits. The defeat appears on the hands of the forming fruit. Usually at the top (tip) of green and ripening fruits, concentric brown spots appear and less often in the peduncle area. Spots can be dented or flat. They increase in size, there is necrosis or softening and decay of tissues.
Noncommunicable diseases are also, with a healthy aerial mass, cracking of the fruit (along the fetus) and “mother-in-law's smile” or “cat's face” (often across the fetus). The appearance of cracks is associated with uneven watering, an overdose of nitrogen fertilizers in top dressing, as well as improper use of stimulants (high concentrations).
Pathogenic saprophytic fungi penetrate into the open tissues of the fruit, causing already secondary infection of plants. Most often, plants indirectly get sick with alternariosis, which is called macrosporiosis or dry spotting. Conidia of a saprophytic fungus penetrate into the fruit through cracks, rotten areas, form a mycelium, outwardly resembling a fluffy coating. Conidia and mushroom hyphae stain dark spots on the fruits in black. Sick fruits fall and serve as a source of soil infection by a pathogenic fungus.
Curative measures against alternariosis, or apical rot of tomatoes
In order to protect the fruits of the culture from infection with alternariosis and other fungal infections, it is necessary to take measures to suppress the defeat of tomatoes with vertex rot. Defeat with vertex rot is caused by insufficient watering (the soil is overdried) and a lack of calcium intake in the plant, due to an imbalance in the nutrition of nutrients.
A single application of complex fertilizers does not eradicate the cause of the disease. It is necessary to regularly, according to the feeding scheme, add wood ash for tomatoes, spray the plants with ash infusion (1-2%) or special preparations that contain calcium, boron, phosphorus, potassium, nitrogen, magnesium and other nutrients. It can be used for feeding Brexil Ca (10 g / 10 l of water with an interval of 10-15 days). After watering, add a solution of calcium nitrate (10 g / 10 l of water) under the root or sprinkle with it plants (5 g / 10 l of water), maintaining a weekly interval.
When processing the aerial parts of tomato plants, it is safest to use biofungicidal preparations. Their processing can be carried out until the harvest. The same biological products are used as for late blight, fusarium and other fungal diseases. To reduce the multiplicity of treatments, it is better to prepare tank mixtures from different types of fungal and use a soil treatment system (through irrigation with bio-solution) and spraying plants with an interval of 7-15-20 days throughout the growing season before harvesting.
Other types of fruit rot of tomatoes
In addition to the top, tomatoes are affected by other types of fruit rot. With improper watering, abundant nitrogen nutrition, planting diseased seedlings, tomato fruits are affected by wet rot, including soft rot, the hallmark of which is the wateriness of internal tissues with an acidic smell of fermentation, pitious rot, in which the fruits resemble a watery ball partially covered with fluffy white plaque. Black masses at the place of attachment of the tomato fruit to the peduncle are a signal to infect the fruit with black mold. After a short storage period, ripe fruits become watery and soft - the first sign of the transformation of hard (rhizoctonia) rot into soft watery.
Therapeutic measures against rot on tomato
If the fruits of tomatoes fell ill with alternariosis, and along the way with other rot: anthracnose, septoria, phomosis, etc., it is possible to protect plants with chemical fungicides by selecting drugs with a short waiting period. These compounds include Quadris (12 ml / 10 l of water), which is treated with plants 3 times per season, but no later than 30-35 days before the fruits ripen. Ridomil Gold MC (0.25% solution) is able to stop the disease during mass development and, moreover, it has a waiting time of only 14 days. Effective suspensions of Metaxil. The preparations Skor, Cabrio Top, Thanos-50, Flint, Antracol and others also work effectively, which should be used according to the recommendations.
If there are few tomatoes on the plot, soil treatment during planting / sowing with a solution of Previkur will help to overcome root rot. The procedure is repeated 2-4 times throughout the growing season.
In order to protect against rhizoctonia, the soil is treated with a suspension of sulfur-containing preparations (0.3%), including colloidal sulfur, Thiovit or Cumulus.
To strengthen the resistance to rot, it is effective to feed the plants with the “Drop” preparation (2 tablespoons per 10 liters of water) at the rate of 1 liter of solution under the bush before flowering. Feeding plants with trace elements and herbal infusions according to folk recipes is also required.
Tomato viral diseases
Of the viral diseases of tomatoes, the tobacco mosaic virus, tobacco necrosis virus, leaf curl viruses, and strick are best known in open and closed ground. Widely distributed, mainly mosaic and streak.
Tobacco Mosaic Virus
Mosaic is manifested by a change in the color of tomato leaf blades (mosaic pattern of light and dark spots of an indefinite shape). Leaves are smaller, curled, wrinkled. Leaves and bush as a whole lag behind in growth, turn yellow. They can form a small crop of small tasteless fruits.
Strick affects the aboveground organs of tomatoes. The disease manifests itself on the stems and petioles of the leaves in the form of oblong necrosing strokes of brown or brownish-red colors. Needle-like spots appear on tomato leaf blades, which dry out over time and become brittle. Petioles easily break, and the fruits are covered with brown furrows, sometimes shiny, irregular in shape.
Therapeutic measures against viral diseases of tomato
Violation of the ratio of nutrients, increased nitrogen and air humidity accelerates the defeat of tomato bushes and the spread of viral diseases. The fight against viral diseases lies in preventive measures.
- For sowing, it is imperative to use zoned, disease-resistant varieties and hybrids of tomatoes.
- It is better to use seeds 2-3-5 years ago.
- The source of infection is stored in the seeds. Therefore, before sowing, tomato seeds must be decontaminated. In the absence of special preparations, the seeds withstand 15-20 minutes in a 1-2% solution of potassium permanganate.
- The soil before sowing seeds or transplanting seedlings is shed with a 2% solution of potassium permanganate. On the day of planting, add a mixture of solutions of trichodermin or phytosporin-M with root in a hole or row.
- There is no treatment for viral damage. Tomato bushes are uprooted and burned. They cannot be used for compost bookmarks. The place where the plant was located is disinfected with a 2-3% solution of potassium permanganate or bleach, in other ways (protected ground).
Bacterial infection of tomatoes
The soil is literally crammed with different types of infections that carry soil fungi and bacteria. It is impossible to completely get rid of infection, but with the right methods of protection, you can maintain a positive relationship between the necessary and negative microflora in the soil. It often happens that the antifungal measures carried out nevertheless provided effective protection. Plants recovered, successfully forming young foliage, young inflorescences appeared and suddenly a new outbreak of diseases. But this time, the symptoms of the disease are not similar to those of a fungal or viral infection. It turns out that the resulting niche was occupied by a bacterial infection, capable of quickly affecting all plants in a large area.
The most malicious diseases are bacterioses:
- bacterial wilting of tomatoes,
- black bacterial spotting.
To a lesser extent, tomatoes are affected by bacterial cancer and other bacterial infections.
Bacterial wilting of tomatoes
The disease begins with the lower leaves of the tomato and spreads rapidly throughout the plant. Leaves without visible changes lose turgor and hang. In a chronic form, longitudinal brown stripes are visible under the epidermis of the stems. Numerous aerial roots are formed throughout the stalk of the tomato in its infancy. When pressed, stained bacterial muddy exudate emerges from the damaged stems, and the brownish-yellow rings of the affected vessels are clearly visible on the cross section. On the fruits, the outer part of the diseased tissue becomes brown, which inside becomes more dense. With severe damage to plants, even seeds become ill.
Bacterial wilting of tomatoes is characterized by the hanging of wilted leaves without discoloration, the release of turbid mucous exudate and the appearance of aerial roots in their infancy.
Therapeutic measures against bacterial wilting of tomatoes
The basis of the fight against bacterial infection are the preventive measures described above in the sections of fungal and viral diseases.
It is recommended to disinfect tomato seeds and process seedlings before planting and before flowering with a tank mixture, with the inclusion of the drug “Copper humate”. Affected plants can be treated with a 0.02% quinosol solution. It is most practical to treat the soil and plants with biological products from the beginning of the growing season and before harvesting. Note that the use of drugs on heavily affected tomatoes will not provide a vivid effect, but will help to maintain strong plants and partially clear the soil of bacterial infection. For this, the soil, after the removal of diseased plants, needs to be treated with a 0.2% solution of phytolavine, phytoplasmin or VRK. These antibiotics will dampen the rate of infection. After a week, repeat the soil treatment with 0.2% solution of glaze, mycosar, INBIO-FIT. According to the recommendations, the same solutions can also be used to treat plants.
Most often, from bacterial damage to tomatoes, they use bactofit, phyto-doctor, haupsin, phytosporin, which suppress more than 60 soil pathogens. It is especially valuable that these biological products actively affect fungal infections.
Black bacterial spotting of tomato
Black bacterial spotting of tomato belongs to the type of the most harmful diseases and in optimal weather conditions quickly develops into an epiphytotic lesion of plants. The disease is terrible because it affects the entire plant, starting from the root system. The disease begins with young tomato leaves on which small brown spots of an indefinite shape appear. Small spots grow, merge into large spots, the center of which stands out as a blackening spot. The spots are necrosizing. Leaves, stems, petioles of tomatoes gradually blacken, curl and fall. On the fruits of a tomato, dark convex points with a watery border grow into ulcerated rounded formations and ulcers.
For black bacterial spotting, a distinctive feature is the blackening of the center of spots on tomato leaves, followed by tissue necrosis.
The disease develops intensely at high temperature. At low temperatures, the disease freezes, but the pathogen remains alive in anticipation of suitable climatic conditions. The viability of the causative agent of the disease persists for a long time. The disease is transmitted through seeds.
Treatment against black bacterial spotting
Be sure to carry out all agronomic activities in the cultivation of tomatoes. The most effective preventive measures are against infection. The preparations used to protect plants from bacterial infection are the same as those for the above infections. It is rational to carry out tillage, vegetative parts of plants and fruits with tank mixtures. This will reduce the number of treatments and increase their effectiveness.
The proposed article describes the characteristic features of some of the most common fungal, bacterial and viral diseases of tomatoes. Using the proposed drugs to destroy the described diseases, it is possible to suppress the spread of a number of concomitant (not described) infectious diseases and get healthy, full-fledged crops.