Why spots appear on tomato leaves and how to deal with them

The appearance of spots on tomatoes is an alarming signal about the development of a disease or other negative changes that adversely affect the health of the seedling. Under no circumstances should this moment be missed: if at least one suspicious spot is detected, you need to carefully examine the entire seedling, identify the cause of its formation and begin treatment.

Only in this case can you not only save the tomatoes, but also increase the amount of harvest. In this article we will talk about the causes of stains, their types, how to get rid of them and what preventive measures should be taken.

Why do spots appear on the leaves and fruits of tomatoes?

There are several reasons for the appearance of spots on the foliage and fruits of tomatoes. The most common is the development of a disease to which tomatoes are most susceptible.. Most often, spots begin to appear in mid-summer or towards the end of fruiting.

The reason for this is temperature fluctuations: Hot and dry weather prevails during the day, cool in the evening, foggy in the morning, as a result of which dew appears on the foliage of tomatoes. Temperature changes can lead to the development of a fungal disease, which will cause spots on the plant.

They can appear when there is an excess or lack of useful microelements, or when the seedlings are not properly cared for.

What does the appearance of the spots indicate?

By the appearance of the spots, they determine what disease the plant is affected by and what exactly provoked their formation. Let's take a closer look at the common options.

If you plant seedlings in the heat, in the scorching sun, the tomatoes will get burned. It appears in the form of light yellow spots on the foliage, which subsequently dries out and falls off. Initially, the spots are located along the edges of the leaves, but after some time they can cover their entire area.

Tomato foliage may become covered with silvery spots. Many gardeners who encounter this phenomenon for the first time are alarmed by this. The formation of these spots is not caused by a disease; they appear during sudden temperature changes and due to a disruption in the physiological development of the plant, and the reason for this is insufficient development of the qualitative characteristics of hybrids before releasing seeds for sale.

If tomatoes are lacking nitrogen, then them the foliage begins to turn yellow, dry out and eventually fall off. After some time, the plant stretches out, becomes covered with yellow spots, and the stem becomes soft, the veins on the leaf turn red-bluish.

For potassium deficiency Tomato leaves turn yellow, curl up and begin to dry out at the edges. Their color becomes darker, yellow-brown spots appear, which become larger over time and form a border.

With a lack of phosphorus Purple spots appear on tomato leaves. At first, the stems and foliage of tomatoes become dark green, and the old leaves on the reverse side acquire a purple tint. The roots of the plant wither, the foliage curls, and the stem becomes stiff and brittle. After some time, the leaves curl upward and are pressed tightly against the stem.

Possible diseases depending on the types of spots

By the appearance and color of the spots, you can determine what disease the tomatoes are affected by. Let's take a closer look at what spots appear with various tomato diseases.

Alternaria blight

With Alternaria blight, tomato leaves turn yellow, brown-brown spots appear on their surface, and spots appear on the top of the fruit. The spots have a round shape, an oval depression of a grayish-brown color, and pronounced zoning. Later, the spots acquire a black tint - the primary sign of Alternaria blight.

Anthracnose

Defeat anthracnose most often occurs towards the end of the growing season. With this disease, the leaves wither and chaotically located depressed spots appear on the fruits. Initially they are small, the same color as tomatoes, and then gradually enlarge, darken and become grayish-brown in color.

Mosaic

Tomato mosaic is a type of viral disease spread by insect pests, contaminated seeds or soil. Once infected, tomato leaves develop a mosaic pattern of yellow and green spots. In young plants the pattern is more clearly visible than in older ones.

Important! Infection of nearby growing tomatoes occurs quickly, so when a disease is detected, it is necessary to get rid of the affected plant as soon as possible - it will not be possible to save it, since the mosaic cannot be treated.

Cladosporiosis

At cladosporiosis First, the lower part of the bush is affected, rusty spots appear on the foliage, after some time they spread to the upper leaves. Later, a velvety dark coating appears on the bush.Tomato inflorescences and fruits are less likely to be infected, but if this happens, they turn brown and fall off.

Attention! Cladosporiosis is a dangerous bacterial disease that can destroy an entire crop in a matter of days.

Septoria

Septoria is one of the most dangerous fungal diseases for plants. When affected, a white coating forms on the leaves and the edges darken. Initially, the lower foliage is infected, and then the disease spreads throughout the plant. If, after detecting such spots, no timely action is taken to eliminate them, then black dots will appear inside the white spots, the leaves will begin to wither and fall off.

Septoria - a contagious disease that can easily infect seedlings growing nearby. The cause of septoria can be poorly treated soil in which fungal spores remain, or the use of infected seeds when planting seedlings. Tomato septoria infection mainly occurs in July, as high humidity and suffocating heat prevail during this period.

Late blight

Late blight - the most common fungal disease of tomatoes. It is formed due to fungi, the spores of which spread quickly, affecting other plants. Spores develop best in shady and damp places. With this disease, the tomato foliage turns black, dries out and falls off, then the same thing happens to the fruits of the plant.

Leaf mold

Leaf mold, or brown rot, appears more often in greenhouses than in open ground. It first affects the lower leaves and then spreads to the upper parts of the plant.

In advanced cases of the disease, tomato foliage completely dies and falls off.This leads to disruption of the photosynthesis process, resulting in a significant reduction in yield.

Reasons specific to greenhouses and greenhouses

Common causes of leaf damage when growing tomatoes in greenhouses:

• lack of moisture;
• contaminated soil;
• improper soil treatment before planting;
• excess or deficiency of beneficial microelements;
• lack of fresh air;
• high humidity;
• hot weather conditions;
• periodic temperature changes in the greenhouse;
• remnants of infected seeds in the soil from last year.

For open ground

The reasons for the appearance of spots on tomatoes in open ground are the same as in greenhouses. There is only one difference: in closed ground, plants are less likely to suffer from diseases.

Additionally, the following factors contribute to the appearance of spots on foliage and fruits in open ground:

• exposure to sunlight;
• temperature fluctuations;
• water getting on the leaves of seedlings when watering;
• incorrectly selected fertilizer;
• treatment with strong chemicals.

Spots characteristic of the leaves of tomato seedlings

Spots on seedlings may appear due to white rot. This is a type of fungal disease, infection with Sclerotinia libertiana Fuckce.

Initially, the disease appears on the lower part of the plant, in places where fruits and leaves are damaged. Development is stimulated by temperature changes, high humidity and dense planting of seedlings.

After infection, the lower leaves of tomatoes become discolored and covered with a white coating. The disease spreads throughout the plant, the leaves dry out, begin to rot and become covered with a fluffy white coating. The fruits of infected plants have a watery structure, their surface cracks, and a white coating also forms on them.

What to do

To treat tomatoes from fungal and bacterial diseases, you can use traditional methods:

1. Treat the seedlings with a 0.1% solution of Bordeaux mixture. If necessary, repeat the procedure every two weeks until the tomatoes begin to ripen. The harvest can be harvested for the first time a week after the last treatment.
2. Dilute 1 tbsp in a bucket of water. l. copper oxychloride and treat the tomato bushes with this solution.
3. Treat the soil surface with wood ash.
4. Treat tomatoes with kefir solution. To do this, dilute 5 glasses of kefir in 10 liters of water. The first treatment is carried out 10-14 days after transplanting the tomato seedlings to a permanent place. The frequency of spraying tomatoes with this solution is once every 7 days. Treatment helps prevent the development of fungal disease.

How to deal with late blight in tomatoes? At the first symptoms treat tomato bushes and soil with a 1% solution of potassium permanganate. If folk remedies do not help save tomatoes from late blight, then chemical solutions should be used to combat the disease.

Dilute 20 g of Oxychom powder (or two tablets) in a bucket of water and process the tomatoes. The drug is used at the first signs of this fungal disease. In total, no more than three sprayings are carried out. After the last treatment, ripe fruits can be used for food no earlier than 5-6 days later.

Prevention measures

To avoid plant infection, preventive measures should be followed:

1. Select seeds carefully before planting.
2. Do not plant tomatoes in the same place every year.
3. In the fall, digging up the soil will help get rid of fungal larvae and spores.
4. After harvesting, thoroughly clean the area.
5. Before planting seedlings, disinfect the soil.
6. If tomatoes are grown indoors, then in the spring and autumn, disinfect the surface and soil in the greenhouse.
7. If infected plants previously grew in the area chosen for planting, replace the soil.
8. After planting plants in the ground, periodically treat them with folk remedies against fungal infections.

Conclusion

If seedlings are grown incorrectly and agrotechnical rules are not followed, the risk of tomatoes becoming infected with diseases increases. If there are any spots on the leaves of plants, it is recommended to urgently identify the cause and begin treatment in order to preserve the plantings and save the harvest.