Diseases of a tomato, symptoms and how to fight?

Dry blotchiness, or alternaria (synonyms: macrosporium, brown spot, early dry spotting) is one of the most common and harmful diseases of tomato.
The disease affects tomato at various stages of its development, beginning with seedlings. It appears on leaves, stems and fruits.

Mass development of the disease occurs at the beginning of the formation of the fruit.
The first manifestations of the disease are observed on the lower leaves.

Gradually, the disease spreads to the leaves of the upper tiers. On the affected areas, rounded concentric brown spots are formed, the diameter of which first is 4-7 mm. Over time, their size increases, and the spots reach a diameter of 10-15 mm. Their shape becomes oval, and a black velvety coating appears on the surface.

Under favorable conditions, the spots, increasing in size, often merge with each other and cover a considerable part of the leaf plate. As a result, this form of manifestation of the disease leads to the death of the leaves. Often amazed and petioles: they appear elongated spots, which they ring and lead to the death of the leaf plate.
When the stalk parts (petioles, peduncles, shoots) are damaged, oblong dents of brown spots are formed on them, and in wet weather they become covered with a black velvety coating.

On the fruits, the signs of the disease are noticeable near the stalk, where rounded dark-brown dented zone spots with a gray-black coating appear.

The pathogen's mycelium penetrates deep into the affected fetus. At the same time, the infected tissue darkens.

Sick fruits fall off, and some of them prematurely ripen. However, their mass is much less than that of healthy ones. It is very dangerous to defeat the fruit during the ripening period, as the mycelium penetrates into the seeds.

The latter lose their luster and acquire a darker shade, their sowing qualities sharply decrease. When they fall into conditions of high humidity, a black coating forms on their surface, which is the conidial spore-bearing of the fungus.
The causative agent is the fungus Alternaria solani Sor. (a synonym for Macrosporium solani Ell. et Mart). The parasite develops in the conidial stage (black patches on the spots).

During congested vegetation, conidia are spread by wind, rain and irrigation water. The pathogen is able to parasitize and on many representatives of the Nightshade family - potato, pepper, eggplant, etc.
The development of dry spotting occurs in hot weather with little atmospheric precipitation, at an air temperature of 25 ... 30 ° C. The disease progresses especially strongly when alternating high temperatures during the day and low temperatures at night. Dew with frequent rains promotes abundant sporulation of the fungus. The presence of mechanical damage to plant tissues contributes to their defeat. Under optimal conditions, the incubation period of the disease is 2-3 days. Tomato varieties are most susceptible to dry spotting.

The source of infection are plant residues, 8 of which pathogen is retained by mycelium and conidia on their surface, as well as seeds containing mycelium of the causative agent of the disease. In the decayed remains, the infection does not persist.
Protective measures. When growing tomato, it is necessary to give preference to varieties with increased resistance to the disease. This helps to increase the yield and reduces the costs of carrying out protective measures. Seeds should be harvested only from healthy areas and fruits. When preparing seeds for sowing, they are thoroughly cleaned with removal of all impurities, pieces of fruit and other parts of plants, since they can be a source of infection.

Seeds are also etched with permitted fungicides.
Correct is the alternation of cultures, in which the tomato returns to its former site no earlier than in 3-4 years. In addition, given that A. so / an / fungus affects potatoes, one should also try not to place these cultures close to each other.
It is necessary to strictly adhere to agrotechnical methods for caring for plants in order to increase their resistance to diseases. In conditions of protected soil, it is necessary to maintain a regime of temperature and humidity that would prevent the progression of dry spot.

Against dry spotting, or alternaria, the following fungicides are recommended: Acrobat MC, (2 kg / ha); Acrobat of the MC, s.p. (2 kg / ha); Ditan M-45, cop. (1,2-1,6 kg / ha); Quadrice 250 SC, c.s. (0,6 l / ha); Kuproksat, k.s. (3-5 l / ha); Metaxyl, sp. (2,5 kg / ha); Speed ​​250 EU, a. (0,5 l / ha); Poliram DF, this year. (2-2,5 kg / ha); Title 50, in the year (0,6 kg / ha); Thanos 50, this year. (0,6 kg / ha); Fital, vr.k. (2-2,5 l / ha), as well as other authorized products. The interval and the frequency of application of fungicides depend on the degree of disease development and the regimen of use.

When working with fungicides, account must be taken of the specifics of the open and protected soil.

After harvesting in the open ground, remove all plant residues and conduct deep plowing with plows with skimmer.

Septoria, or white spotting

The disease is spread mainly in the open ground, but it can be seen in seedlings in greenhouses and in greenhouses in the form of separate foci, white spotting occurs almost everywhere, where tomato is grown, but especially in areas with sufficient moisture.

According to the State Plant Protection Inspectorate, in the 2005 very wet year, epiphytotyping septoriosis on tomato was noted in the Mykolayiv region, where the damage to plants was 100% when the disease developed 4-28% (in individual farms of the region and in individual fields - 34-49%). In other areas, the spread of the disease was 6-74%, and its development was 4-18%.

Septoria appears on the leaves first of the lower tier, and then the middle and upper in the form of shallow, first brown, later dirty white patches with a dark brown border (Fig. 1, 2, 3). The spots appear during the entire vegetation period, especially on adult plants (Figure 4). On the surface of the spots, you can see scattered small dark points - the fungus pycnidia. The spots often merge, forming large areas of necrotic dead tissue with many small dark dots. It should be noted that the size of the spots on the tomato leaves depends on the level of resistance of the variety to the disease. In resistant varieties and hybrids, spots on leaves usually form very small (up to 1-2 mm in diameter), on their surface pycnidia are formed in rare cases.

On the leaves of susceptible varieties and hybrids, the spots are large (up to 3-6 mm in diameter), abundantly covered with pycnidia of the fungus.
On the stems, the stems are elongated, ellipsoidal, at first dark brown, with time the affected tissue in the center of the spots becomes light, becomes light gray, with a large number of dark spots - the fungus picnid. At the border between the healthy and affected tissue, a dark brown border is clearly visible, at first wide, then it becomes very narrow (Figure 5, 6). Signs of septoriosis can sometimes appear on green fruits. Especially strongly affected by Septoria early varieties.
The affected leaves are twisted, necrotic and die.

With high air humidity and high temperature, the disease rapidly progresses and causes premature dying of both individual leaves that are boring and falling off, and whole bushes (Figure 7).
The causative agent of the disease is an imperfect fungus - Septoria lycopersici (Speg) Sacc. In addition to tomato, the fungus infects potatoes, eggplant, black nightshade and some other crops to a weak degree.
In infected plant tissue, the fungus forms a colorless mycelium that extends through the intercellular spaces, and beneath the epidermis of the columnar parenchyma of the leaves forms asexual sporulation in the form of dark dots-pycnidia with pycnospores.

Mushroom pycnidia are spherical, black, with a diameter of 150-200 μm, with a wide outlet - stomata.

Inside the pycnidia, colorless, filiform, slightly curved, with several transverse septa (3-11), pycnospores 50-120 × 2-3 microns in size, which are found in colorless mucus, are formed.

The fungus is distributed in nature through pycnospores. Once in a tomato plant, pycnospore sprouts infectious hyphae that penetrate plant tissue directly through the cuticle. Intensive development of septoria is observed at a temperature of 20 ... 25'C and relative humidity of 75-100%. The incubation period of the disease lasts, depending on air temperature, 8-14 days. A particularly strong development of the disease is observed on cloudy days, with high humidity, an abundance of rain with the wind. Intensive death of leaves and whole bushes occurs when joint pathogens of septoria and alternariosis. During the growing season, the fungus forms several generations.

The source of infection are affected plant remains, in which pycnidia with pycnospores are conserved. The overwintered pycnospores emerge from the pycnidia and infect seedlings near the soil surface. In the future, the causative agent passes to adult plants. Piknospores formed on infected leaves in wet weather, come out of pycnidia, then rain, wind, and also by man (hands, clothes, inventory) are transferred to healthy leaves, causing their massive infection.
The harmfulness of the disease manifests itself in the premature drying of the leaves, which, in turn, delays the development of plants. In addition, a part of the plastic substances a diseased plant spends on the formation of new leaves, which ultimately affects the formation and growth of fruits. In some years, septoriosis may be the cause of a decline in yield on 30-40 and even 50%.

Effective methods and measures to combat septoriosis:

• Destruction of plant residues (especially important in greenhouses). Vegetable residues are destroyed when deep plowing or field digging is carried out.
• Compliance with crop rotation. It is forbidden to plant tomatoes in the same place for three years!
• Observance of spatial isolation between the planting of tomato and other nightshade cultures. You should not take away the fields for the current year's tomatoes next to the fields where tomatoes were grown last year.
• Disinfection of greenhouses, greenhouse frames, boxes and greenhouse equipment. Land for greenhouses should be taken only from areas where tomatoes have not been grown for 3 years, or use a greenhouse mixture prepared in self-heating piles or disinfected.
• The single infected plants found in the greenhouses must be removed and destroyed.
• When the first signs of the disease appear, it is necessary to spray the plants with fungicides (usually for 2 weeks before planting the seedlings into the ground) and repeat it every 12-14 days.

In the production conditions, on plantations of tomato against septorio, for the treatment of plants with fungicides: Thanos 50, 0,6 kg / ha; Title 50, this year, 0,6 l / ha and Revus 250 SC.KC, 0,5 l / ha.

Fungicides used on tomato against late blight and alternaria (Alpha-Copper, spp, 3 kg / ha; Acrobat MC, sp or v, 2 kg / ha; Aspect, WR sp, 2kg / ha; DitanM-45s.p., 1,2-1,6 kg; Efatol, spp, 2 kg / ha; Infinito 61 SC, 687,5, c.s, 1,2-1,6 kg / ha; Kuproxat, ks , 3-5 kg / ha; Ridomil Gold MC 68 WG, 2,5 kg / ha; Metaxyl, spp, 2,5 kg / ha; Ordan, sp, 2,5-3 kg / ha; Penkotseb, sp, 1,6k / ha; Rincotseb, sp, 2-2,5 kg / ha; Sinekura 680, sp, 2,5 kg / ha; Speed ​​250 EC, ae, 0,5 l / ha, Tattu, ae, 3 l / ha; Quadrice, c.s, 0,6 l / ha; Poliram DF, as, 2-2,5 kg / ha; Fital, vr.k., 2 -2,5 l / ha; Charivnyk, pp, 1,5-2,5 kg / ha; Shir-lan 500 SC, cc, 0,3-0,4 l / ha; Junker, sp, 2,25 kg / ha) markedly inhibited the development and septoriosis.

The rate of application of the working solution of the fungicide during ground processing is 500 l / ha.

On homestead plots against septoriosis, tomato plants are sprayed with allowed fungicides: Thanos 50, vg or Title 50, cp (calculated by 15 g for 10 L of water at 2,5 weave). During the vegetation period of tomato is allowed up to 4 sprayings.

Applied on personal plots against late blight and alternaria, fungicides Alfabogatyr, sp. (25 g), Acidan, sp. (25 g); Ditan M-45, sp (20 g); Zahist, s.p. (15-20 g); Quadrice 250 SC, c.s. (6 ml); Metaxyl, sp. (25 g); Ridomil Gold MC 68 WG, in the year (25 d); Speed ​​250 EU, a. (5 ml); Фи-тал, в.р.к. (20 ml); The Cynician, sp. (25 g), Charivnyk, sp. (15-25 g); Champion, s.p. (20 g); Chemp, vg (20 g), based on 5 liters of water per 1 weaving significantly inhibited the development and septoriosis, too.

Seed preparation should only take place from healthy areas of tomato and from healthy fruits. Seeds must be decontaminated by aging seeds in warm water at a temperature of 48 .. .50 ° C for 20 minutes, followed by cooling in running water for 2-3 minutes and etched with base, sp, 5-6 g / kg.

The most radical, economically profitable and ecologically safe method against tomato septoria is the removal and introduction of resistant varieties into production. There are no immune strains for the disease.

Less affected by septoriosis is zoned varieties and tomato hybrids: Amiko, Ballad, Beryl F1, Joker, F1 Dish, Worthy F1, Golden Fleece F1, Copper, Mondial, Dressed, F1 Plate, Shasta, Horeb.

Also, the frequent question:
I started to have spots on the leaves and fruits on the tomatoes, which are ripening, they start to turn black in some places. Prompt, what is this illness or disease and as with it or her to struggle.
Answer:
Probably it is macrosporia or phytophthora.
The disease is most often manifested in the second half of the summer, in June-July. Disputes of phytophthors are carried by the wind and even by the person himself when working in the garden.

The rapid spread of infection contributes to excessive moisture, dew, fog and a moderately low night temperature. A particularly favorable microclimate for the disease is created in poorly ventilated greenhouses. Unfortunately, at the moment there are no varieties of tomatoes, completely resistant to this disease.
There are several ways to combat phytophthora. Among the gardeners is distributed such a recipe: 20 tablets antimicrobial medicinal product "Trichopol" dissolve in a bucket of water.

Spray the resulting solution with plants that may be affected. As practice shows, this is a fairly effective way to prevent late blight. If the symptoms of the disease are detected late, you can’t do without a stronger drug - the Tammy fungicide

In this case, the fruits can be eaten no earlier than three weeks after treatment with the drug. Against late blight, in addition to the mentioned “Tattu”, first of all we recommend “Infinito”, “Ridomil Gold”, and if the fruits are already blushing - “Quadris”.

Affected tomatoes should be thrown out, as for consumption in food they are not suitable.

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