Common diseases and pests of tomatoes, as well as methods of their treatment

 Common diseases and pests of tomatoes, as well as methods of their treatment

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Most people in one way or another are engaged in gardening in the open ground, or in the countryside in greenhouses, or in the city on the windowsills at home, but everywhere there is a threat of diseases of tomatoes and their seedlings.

These are bacterial, viral, fungal diseases, various pests, the consequences of improper watering, fertilization and non-observance of other conditions.

So that the gardener is not afraid for his harvest and is ready to defend his plantings, the article will provide information on what tomatoes are sick with and on how to fight diseases.

Fungal infections and their description and treatment

Late blight

The danger of this disease lies in its simple method of transmission from one plant to another and in a wide range of threatened plants, which include peppers, tomatoes, eggplants, buckwheat, apple trees and others. The causative agent of this disease is the Phytophthora fungi, which spread through spores.

The appearance of late blight can be determined by brown-gray spots, often surrounded by a ring of light mold. Due to the disease, the affected leaves die off, which can often lead to the death of the entire plant. Affected fruits lose both their appearance and taste.

On different plants, the manifestation of late blight is different, but we will give the main measures for the prevention and treatment of this disease:

  1. moderate watering;
  2. the use of potash and phosphorus fertilizers;
  3. hilling;
  4. adherence to planting schemes, for some of them to make it more rarefied;
  5. destroy falling fruits and leaves in time;
  6. soil sterilization.

Alternaria or macrosporiosis

The causative agent of this disease is Alternaria fungi, which infect various garden, flower and horticultural crops. It manifests itself depending on the plant with some differences, so let's talk about them. In tomatoes, Alternaria affects the aerial part: leaves, stems, fruits.

It is possible to determine the appearance of Alternaria in tomatoes by the presence of dry, clear spots of gray-brown color. Affected leaves turn yellow and die off, and the fruits lose their appearance and taste. On potatoes, in the presence of Alternaria, dark spots appear on the tubers and leaves.

Reference: when grape plantations are infected, light yellow or silvery spots appear on its leaves, which darken over time, after which the leaves dry out. The berries are covered with a metallic sheen, and then a dark gray fungal bloom.

When signs of alternaria appear, the plants should be treated with a solution of copper sulfate and other fungicides. Spraying should be done every 10-14 days. Early prophylaxis can be carried out using Trichodermin, which should be sprayed on leaves and stems in April or May.


A fungal disease that affects cucumbers, melons, tomatoes, cherries, grapes, strawberries, raspberries and other crops. The causative agent is a fungus of the genus Colletotrichum. This disease spreads in conditions of high humidity and medium temperatures.

Signs of the appearance of anthracnose are brown spots with a dark brown border on the leaves of plants, which grow further over time. As the disease progresses, the spots develop a brown or dark purple rim.

Treatment options will vary depending on the culture affected.

Here are the main anti-anthracnose remedies:

  1. removal of affected parts of the plant;
  2. spraying with a solution of copper oxychloride or 1% bordeaux liquid (for tomatoes);
  3. spraying with a 1% suspension of colloidal sulfur (for cucumbers).


Septoria (white leaf spot) is caused by a fungus of the genus Septoria. It is possible to identify the infection of crops with this disease by dark red or light brown spots, which are surrounded by a yellowish border around the edges. Dark spots are visible in the center of the spots. Infected leaves and stems gradually dry out and acquire a brown color.

High humidity at medium temperatures aids in spreading. The danger of the disease lies in its rapid spread to other plants.

The treatment of septoria will help:

  1. 1% solution of Bordeaux liquid;
  2. colloidal sulfur solution;
  3. copper sulfate solution;
  4. strobes in consumption with various fungicides.


The causative agent is a fungus of the genus Cladosporium fulvum. The appearance of this disease can be determined by the rounded yellow-brown spots, which turn into reddish-brown colors as the disease progresses.

Cladosporia spreads under conditions of high humidity and medium temperature. With a disease, the leaves gradually begin to curl, after which they dry out, depriving the plant of the possibility of photosynthesis, which leads to its death.

To combat cladosporia and its treatment, you need:

  1. ventilate greenhouses;
  2. remove old leaves;
  3. disinfect the soil;
  4. spray with Pseudobacterin-2;
  5. spray Abiga Peak.

Gray rot

It is possible to determine the appearance of this disease by the light brown spots that first affect the stems, which are subsequently covered with a gray fluff, and then all this goes to the fruits. The gray rot affects vegetables, berries, flowers, cereals, and fruit. The disease, affecting the leaves and stems, leads to their death, and with a strong infection, the plant also dies, since due to the disease the process of photosynthesis is either hampered or completely impossible.

If there are signs of gray rot, you must:

  1. Treat the plants with a mixture of chalk, wood ash, copper sulfate and 10 liters of water, this is enough for 2-3 square meters of planting.
  2. Use Bordeaux liquid or copper oxychloride. Such drugs as Teldor, Horus, Switch are suitable.

White rot

The causative agent is the fungus Sclerotinia sclerotiorum, which affects a large number of different crops. This disease can be identified by the appearance of a white growth on the leaves, similar to cotton wool, and the leaves themselves become watery. The spread of white rot occurs in high humidity conditions.

The following medications can help treat white rot:

  • Rovral.
  • Abiga Peak.
  • Hom.
  • Acrobat MC.
  • Ridomil Gold.

All affected plants must be removed along with the topsoil, after which the plantings must be sprayed with fungicide solutions.


The causative agent of brown rot is a fungus of the genus Pseudomonas solanacearum, which is found in the soil. It mainly affects potatoes, but it can transfer from it to tomatoes. This disease can be determined by the general wilting of potato bushes, brown stems and soft root part of the plant. If you press on the affected stem, brown mucus will come out.

Tubers also suffer - if you cut them, you can find brown circles. After the development of brown rot, mucus will also begin to be released from the tubers. Well-selected potatoes, phyto-cleaners, which help to exclude damaged and aching tubers, will help to exclude the possibility of the appearance of brown rot.

Powdery mildew

A fungal disease that spreads very quickly, since the spores of the pathogen fungus are easily airborne, as well as together with water or on the tools and hands of the gardener.

Powdery mildew is a white bloom on leaves, stems and peduncles. Also, the leaves will turn yellow, wither and fall off. Powdery mildew symptoms can be modified depending on the plant. Ultimately, the plant can easily die.

To combat powdery mildew, it is necessary to monitor the condition of the plants, remove all affected leaves.

You can use fungicides to treat plantings:

  • Topaz.
  • Coming soon.
  • Jet.
  • Tiovit.
  • Cumulus.

Potash and phosphorus fertilizers can be added to the soil.


Root rot is caused by fungi of the genus Rhizoctonia, Phytophthora Pythium. This disease can be identified by the blackened roots and legs, which then begin to rot, which leads to the death of the plant. Also, if there is a lethargy of the plant, drying of the leaves, the formation of brown spots, it must be borne in mind that this can also be the consequences of the formation of root rot.

It will no longer be possible to cure the affected plants, but measures must be taken to protect the remaining plantings. Recommendations for different plants are different, but here are the main ones:

  • do not abuse watering;
  • remove affected plants along with a small part of the soil;
  • avoid acidic soil;
  • monitor the temperature of the soil;
  • feed the plants, but do not overdo it;
  • avoid high soil moisture or drying out.

Bacterial diseases

Bacterial wilting

The causative agent of bacteriosis is Pseudomonas solanacearum. If an acute form of the disease is affected, it is impossible to identify it, and the plant simply withers and dies. In the chronic variant of the disease, brown longitudinal stripes begin to appear on the stem. The leaves begin to turn yellow, the growth of the plant slows down, the existing fruits grow small and fall off.

When cutting the stem, you can find brown-yellow rings on the vessels of the plant, which are filled with disease-causing mucus. Something similar to apical rot appears on the fruits, the fruits turn brown on the surface. The bacteria are in the soil, after which they enter the stem through the roots.

Tomato stem necrosis

The causative agent is Pseudomonas corrugata. The manifestation of necrosis occurs during the formation of tomato brushes. Spots from necrosis on the stems are brown-brown, elongated and depressed. A bacterial mass accumulates in the vessels of the plant, which then flows out of cracks and wounds.

When cutting the stem, necrosis of the pith can be detected. The necrosis itself proceeds as follows: first, the core is saturated with water, then it becomes glassy, ​​then darkens and dries up. At the same time, outwardly, the stem looks healthy. The leaves at the top of the plant wither, darken and lose their turgor. The fruits are covered with a net of light veins; when cut, they can reveal necrosis of the seed coat.



The causative agent is Tomato mosaic tobamovirus. The infected plant slows down in growth, the fruit grows defective, the yield decreases, if the plant is severely damaged, the plants die, and the fruits do not appear at all.

The symptoms of mosaic are the appearance of mottling on the leaves, which turns into a dark or light green mosaic. Deformation of the leaves occurs, their plates wrinkle, and the fruits become smaller.

Attention: the mosaic virus is very resistant, thermal inactivation occurs over 95 degrees Celsius.

The virus is transmitted through aphids and thripsas well as through the gardener's tools or hands.

Chlorotic curl of leaves

It manifests itself in a change in the color of the plant from dark green to lighter colors. Caused by tobacco necrosis viruses and tobacco mosaic.

It is transmitted through contaminated soil and seeds. When tomatoes are affected, the leaves begin to curl and bend. The growth and development of the plant slows down.

Today there are still no hybrids resistant to this disease., so you need to be on your guard.

Non-infectious ailments

Apical necrosis

It occurs in the area of ​​the flower scar in the form of whitish and brown spots that appear on the fruits. With internal lesion, necrosis covers up to 1/3 of the apex of the fetus.

Also, the disease is occasionally characterized by the formation of black and brown depressed spots. Top rot on tomatoes manifests itself with a lack of Ca2, acidity of nutrient solutions, high air humidity, elevated temperature. There are hybrids that are resistant to top rot, such as the F1 Bolero.

Fruit cracking

It can occur under conditions of abundant watering in hot weather or at elevated temperatures, due to which the skin becomes hard, and then cracks. Excessive plucking of the bushes can also lead to cracking, since the plant will have nowhere to put excess moisture, and it will send it to the fruit.

Lack of nitrogen, phosphorus, copper, potassium, calcium can also lead to cracks in the fruit.

A yellow or green spot near the peduncle

This is a fairly common phenomenon and there are several main reasons.:

  • Varietal feature, the so-called GREENBACK of this or that variety or hybrid, for which this is considered the norm, for example, “Black Moor” tomatoes, “mushroom basket”.
  • The second reason is unbalanced diet. The introduction of fertilizers without taking into account the composition of the soil and nutrients that are in an accessible form, high or low acidity, the abuse of fertilizing, especially nitrogen, causes uneven color of the fruit.
  • The third reason for incomplete ripening of tomatoes may be an elementary lack of sunlight due to the "thickening" of the planting, but also, in turn, a lot of sun (with insufficient watering) can negatively affect the ripening of the fruit.

Silvery spots

Basically it is not recognized as any disease, but is only a deviation from the norm. The reasons are as follows:

  • sharp fluctuations in temperature;
  • genetic abnormalities.

Oedema (edema) - edema of the leaves

Also not recognized as a disease. This happens when the soil is warmer than the air or at high humidity. May be accompanied by raised spots that look like white mold. The main reason is the overflow of landings. It is necessary to ventilate greenhouses more often, to normalize humidity.

A photo

Next, you can see a photo of tomato diseases:

Seedling diseases and its treatment

Seedling processing

Plants need to be processed depending on the disease and the type of plant; the most common substances for these purposes are:

  • Copper sulfate and fungicides.
  • Trichodermin.
  • A solution of copper chloroxy or 1% bordeaux liquid.
  • 1% suspension of colloidal sulfur.
  • Pseudobacterin-2.
  • Abiga Peak.


For effective prevention of tomatoes, we recommend the following measures:

  • moderate watering;
  • the use of potash and phosphorus fertilizers;
  • hilling;
  • compliance with planting schemes;
  • destroy falling fruits and leaves;
  • soil sterilization;
  • airing greenhouses (read about all diseases of tomatoes growing in greenhouses here);
  • disinfect;
  • soil to monitor the temperature of the soil.


Pests cause a lot of trouble for gardeners, because they can pretty much spoil the harvest at their summer cottage.
The main pests of tomatoes are:

  1. The scoop is a nocturnal pest, lays eggs on tomato leaves.
  2. Wireworm - damages stems and roots.
  3. Medvedka - gnaws the stems underground.
  4. Whitefly - uses plant sap for nutrition, which causes the leaves to become covered with bloom.


There are a lot of threats to your favorite plants, and you should always be attentive to their condition if you want to taste delicious fruits. Although diseases are quite terrible in their consequences, almost all of them can and should be fought. It is especially important to carry out measures to prevent the occurrence of diseases. Plant gardens, grow plants, keep safety in mind and get a wonderful harvest!

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