What to do if brown spots appear on tomatoes: photos of affected tomatoes and ways to save them

Brown spots on tomatoes indicate disease or unfavorable growing conditions. There are many reasons for the occurrence of such symptoms on the leaves and fruits of plants. In this article we will tell you what to do if brown spots appear on your tomatoes.

Causes of brown spots on tomatoes

Brown spots on leaves, stems and fruits of tomatoes arise as a result of a significant number of reasons.

Diseases

Brown spots on tomatoes are caused by fungal diseases. To recognize the disease and choose the right treatment, consider the following factors:

• color of spots,
• their localization (on leaves, fruits, stems, tiers of the plant),
• appearance and shape of the lesions,
• development of the disease.

Late blight

In the early stages of development disease manifests itself as partial yellowing of the leaf. Subsequently, a gray-brown necrotic spot with an extensive yellow halo forms at this place. With rapid development of the disease, yellowing may be absent. Leaves curl and dry out.

With a high infectious background, humidity and coolness, late blight develops rapidly and affects the entire plant, including stems and green fruits. They also become covered with brown spots and rot.

The photo shows tomatoes affected by late blight.

Cladosporiosis

At the beginning of the disease, pale green, often symmetrical, spots are visible on the leaf blade, which then take on a bright yellow color. Turn the sheet over to face you: olive-gray swellings with edging and a whitish halo will be visible. These are places where the fungus spores. With absence treatment leaf blades dry out and crumble.

Attention! With cladosporiosis, the lower tiers are the first to suffer. Then the disease spreads to the upper leaf mass, as well as to the fruits. Tomatoes become watery and tasteless. The plant dries out.

Alternaria blight

Alternaria blight is otherwise called macrosporiosis, or dry spotting. You can easily identify the disease by the dry dark brown spots randomly located on the leaves and fruits. They are easily distinguished from other fungal lesions by their concentric circles, inscribed within each other and as if pressed into the affected plant tissue.

At an early stage, the spots are located on the lower tier of leaves, then move to the stalks and green fruits. Small areas of damage resemble black plaque. They gradually increase in size and cover the entire area of ​​the affected tissue and fruits.

On the trunk, the disease appears as oblong brown-gray lines. In this case, it is no longer possible to save the plant.

Anthracnose

Disease At first it is asymptomatic. The first signs of anthracnose are usually observed on ripe vegetables, often after harvesting. But green tomatoes with poor immunity are also affected by the fungus.

Small round lesions form on the fruits, as if pressed into the skin. Later, dark concentric rings appear around them.

Reddish-brown spots with a dark or yellow halo around them gradually form on the leaves, as a result of which the leaf dries out. As the lesions increase, the stem becomes brownish-purple in color.

Mosaic

The disease is classified as viral. The color of the leaves becomes uneven - from bright green and yellow to pale.

The leaf blades of a plant affected by tobacco mosaic are formed unevenly, resulting in tubercles forming on their surface. Subsequently, the leaves curl and wither, and the bush dies.

Reference. There is no effective treatment for mosaic virus. If one of the bushes becomes infected, remove it from the garden bed and burn it. Preventing the disease will help reduce the risk of infection to a minimum.

Gray rot

The disease manifests itself as spots of a gray-brown hue, which gradually become wet and become covered with a fluffy whitish coating of mycelium. The disease primarily affects stems injured during gartering.

On leaves, stems and stalks, the spots most often have an oblong shape, while on green fruits they are round.

Apical rot

The disease affects fruits at the stage of their growth in the apical area: dry or, conversely, watery depressed spots of brown-black color appear on the tomatoes.

Tomatoes begin to rot instead of ripening.

The cause of the disease is calcium deficiency and excess nitrogen in the soil. Lack of moisture in the soil also plays a significant role.

Brown rot, or fomoz

At the beginning of the disease, round yellow-brown spots with dark specks of fungal spores inside become noticeable on tomato leaves. The disease also affects stems and fruits.

A brown rotten spot appears near the stalk.Its size is 3-4 cm, but already at this stage the tomato inside is completely rotten. The affected area becomes lumpy and easily pressed when pressed.

Root rot, or blackleg

The fungal disease is manifested by general wilting of the plant and damage to the stem in the lower part.

First, brown dark spots appear on it, over time they increase, the leg becomes black, a constriction forms, and the tomato dies.

Pests

Pests that cause damage to tomatoes include:

1. Insects, affecting the above-ground parts of plants, often carry viruses, bacteria, and fungi. In particular, mosaic is spread by aphids, mites, and beetles. Bacteriosis is caused by leafhoppers, aphid. Slugs and stink bugs feed on tomato fruits, leaving holes in them.
2. The root system of tomatoes is damaged by pests such as beetles, wireworms, and mole crickets. They are able to feed on the roots of plants, as a result of which tomato bushes wither, the leaves turn brown and fall off.

Agrotechnical errors

Excessive feeding of tomatoes with nitrogen promotes the development of rot.

Another factor that provokes the formation of spots is a deficiency of microelements:

1. Potassium - manifests itself as a marginal leaf burn. The process begins with the tip lightening, then the leaf turns brown. Brown-yellow stripes form inside the fruit.
2. Zinc - gray-brown and bronze spots appear scattered throughout the leaf blade, the edges curl upward. Young leaves are covered with small yellow dots.
3. Calcium - develops top rot.
4. Bora - the growing point of the tomato turns black and dies.

Another reason for the appearance of spots is soil phytotoxicity:

1. This is caused by the excessive use of fertilizers and toxic drugs for treating diseases.The plants themselves also release toxins during their life processes.
2. When tomatoes are grown in one place for several years, an increased infectious background is formed.

To prevent the negative impact of soil on plants, in greenhouses to combat diseases, use biodegradable and organic preparations based on Bacillus subtilis and Trichoderma, and also use green manuring of the area.

Why do brown spots appear on tomatoes?

The development of tomatoes, their immunity and susceptibility to diseases are significantly influenced by the place and growing conditions.

In a greenhouse/greenhouse

In the greenhouse Due to the high infectious background and non-compliance with crop rotation, fungal diseases of tomatoes such as late blight, cladosporiosis, and alternaria most often appear. This is also facilitated by insufficient ventilation, leading to high humidity and condensation.

Greenhouses and greenhouses, to a greater extent than open ground, are characterized by phytotoxic soil.

In the open ground

Brown spots on plants in open ground are often the result of sunburn due to changeable weather or improper watering.

The alternation of rainy and warm days and an abundance of dew contribute to the development of fungal and bacterial diseases. Late blight and gray mold are found everywhere.

In the open ground It is more difficult than in a greenhouse to stop the spread of insect pests.

What to do: how to treat tomatoes

After determining the likely cause of the spots on your tomatoes, analyze possible methods to correct the problem.

If fungal diseases are detected, use the following medications:

1. Chemical. The most effective of them are copper-containing “HOM”, Bordeaux mixture.Also used are the potent “Bravo”, “Ridomil”, “Rovral”, “Topsin-M”, etc.
2. Biological. At the beginning of the disease, as well as for small lesions, give preference to biological fungicides. They belong to low-hazard class IV drugs. These are the drugs “Alirin”, “Gamair”, “Fitosporin-M”, “Trichodermin”. The fruits can be eaten within a short time after processing (see instructions). The drug "Fitolavin" (belongs to class III) has an antibacterial effect, but will help in the fight against fungal infections.
3. Folk. At the very beginning of the development of the disease, spraying with a whey solution with the addition of “Farmayod” is used.

When using chemicals, strictly follow the instructions, observe safety precautions and processing times. The active substances of the drugs accumulate in plant tissues, so the fruits become toxic for some time.

Preventive measures

Start fighting fungi and infections with autumn disinfection of the soil and greenhouse:

1. Dig up and etch the soil with copper-containing preparations, treat trellises, racks and polycarbonate.
2. Change crop planting locations, taking into account the rules of crop rotation.
3. Use radish and mustard for digging as green manure.
4. Disinfect seeds before planting.
5. Clean garden tools regularly. Diseases are transmitted through soil, water, and plant sap.
6. After planting seedlings in the ground, once every 2-3 weeks, carry out preventive treatments against diseases using biological fungicides and Bacillus subtilis preparations.
7. Inspect your plants regularly to help identify problems early.
8. Do not thicken the plantings; trim leaves and shoots in a timely manner.
9. Do not allow excessive humidity in the greenhouse. Use drip systems and water the tomatoes generously but rarely.
10. Provide the tomatoes with adequate ventilation. At night temperatures of +18°C, leave doors or windows open around the clock.

Advice from experienced farmers

Experienced gardeners recommend:

1. To prevent diseases, pay attention to preventive measures. Regularly treat the greenhouse with preparations based on Bacillus subtilis or Trichoderma.
2. In autumn or spring, disinfect the greenhouse with copper sulfate, sulfur bomb or peracetic acid. Dig up the soil using the bayonet of a shovel.
3. Maintain crop rotation and change the soil in the greenhouse every 5 years. This will get rid of increased infectious background and soil toxicity.
4. Carry out regular control of insect pests - carriers of viral infections and bacteriosis.
5. Plant tomatoes at a sufficient distance for ventilation. Take into account the varietal characteristics of tomatoes and the need to form several or one stem.
6. Choose varieties for planting that are resistant to diseases that are common in your region.

Conclusion

If you find brown spots on tomatoes, determine the cause of their appearance. In case of illness, use fungicides or antibacterial drugs for treatment.

Destroy pests and eliminate micronutrient deficiencies. To prevent problems in the future, follow preventive agricultural practices.