Cause of white spots on tomato leaves
White spots on tomato leaves are an alarming bell for a gardener. If you notice white spots on tomatoes - this is a symptom of one of the rather serious diseases. The main causes of many ailments of cultivated plants are improper care or the invasion of pests. The first step is to find out what you did wrong.
Cause of white spots on tomato leaves
Why are tomatoes sick?
White spotting of tomato leaves is immediately noticeable, it is very difficult to miss. The danger is that literally in a couple of days white spots begin to appear on healthy plants, if radical measures are not taken. The first thing to think about, after which there was a structural change in foliage. Most often, this is preceded by excessive waterlogging of the soil as a result of watering or heavy rainfall or after the seedlings have been moved to a new place.
The main reasons provoking the appearance of fungal infections:
- waterlogging of the soil;
- insufficient amount of vitamins in the soil, mainly calcium and phosphorus;
- elevated temperature, with high humidity.
Why infection occurs
When tomatoes appear white spots on the leaves, this means that you need to urgently look for the cause of the disease and, if possible, carry out treatment. Based on the above, the main reasons for the development of all kinds of diseases and lower yields are improper care of garden crops.
Fungal infections appear as a result of waterlogging of the soil, insufficient air exchange, as well as increased air temperature. Diseases that provoke the appearance of cavities inside the stem and fruits appear as a result of a lack of trace elements and watering.
Description of the most common ailments of the stem and leaf part
A possible cause of the disease can be determined by the localization of the spotting. Often, when transplanting tomatoes into the open ground, white spots appear on the upper leaves when direct sunlight falls on them. In this case, white spotting is caused by a sunburn. This is because the plants were not hardened before transplanting. As a result of a sunburn, tomatoes die very rarely and with normal further care, they can quickly recover and give a normal crop.
The next reason may be septoria - a fungal disease that manifests itself as white spotting, localized initially on the lower edges of the deciduous part, and eventually spreads further and causes damage not only to the stem, but also to the fruit. Most often, infection with fungal spores occurs through infected soil or the seed has already been infected.
Symptoms of the disease begin to progress in July, when favorable conditions for spore growth are observed. Spores begin to grow most quickly in a moist, warm environment.
Mosaic and cladosporiosis as an alarm bell
Most often, a mosaic disease affects tomatoes that grow in the open ground. Its characteristic feature is the appearance of colorful spots on the leaves. It is impossible to cure it, therefore, if all the white or yellow spots have already appeared on the tomatoes, the affected bushes will have to be removed. A photo of a mosaic disease gives an idea of how serious such an ailment is.
White spotted tomato can be the beginning of such a serious disease as cladosporiosis. Over time, the spots become gray or brown and resemble rot in appearance. Not only green shoots and leaves are affected, but also appear on the fruits over time if the disease is in an advanced stage.
Powdery mildew sick tomatoes in a greenhouse
Most fungal infections of tomatoes are transmitted by spores downwind, and mainly develops when grown in a greenhouse. White spotting of tomatoes can be triggered by powdery mildew.
A white coating appears on the inside of the leaves. Most often, the disease progresses in plants that are grown in a greenhouse. As a rule, symptoms begin to appear in March if preventive disinfection of the premises has not been carried out.
White spotting can be observed at all stages of plant development. The disease can occur not only on the stems and foliage, but also on the fruits. More often near the peduncle there is the appearance of a small area of yellow or green color, with a densified structure. Often, this is the result of too bright lighting. It is recommended to slightly dim the light during the flowering period of tomatoes and the immediate ovary, as well as during the ripening of the fruits.
It is necessary to organize optimal ventilation of the greenhouse, regular moderate watering of tomatoes using top dressing. Often in crops grown in a greenhouse, the flesh remains stiff, despite the fact that, it would seem, the fruit is fully ripe. The structure may be uneven, in some places wavy and covered with small cones. Such symptoms are caused by insufficient potassium or a violation of the temperature regime. The way to deal with the disease is the same as in the previous case.
Viral infection can cause hollow fruit. They remain edible, but the pulp has a low juice content. To combat the disease, regular watering with top dressing, planting in places without drafts is recommended. It is not recommended to use chemicals and herbicides, artificial pollination is ideal.
Disease Prevention Methods
As such, treatment for white spotting practically does not exist, basically, these are preventive measures. In order to be able to prevent infection by fungi, the seed material is soaked in a solution of potassium permanganate before planting or treated with fungicides. This is the first step to getting a good harvest. You also need to take care of the quality of the ground mixture in which the seeds will be sown. It is better to purchase universal soil in the store, if the soil is taken from the street, then it is better to fry it in the oven.
Such a move will help prevent any infectious disease and pest infection. So that the leaves do not become covered with white spots when transplanting them into the open ground, first, about a month in advance, it is necessary to begin the gradual hardening of the seedlings, exposing them to lighter rooms in the sun, but in no case under direct sunlight. It is important to remember that the stem and leaf part are responsible for the processes of photosynthesis. Damage due to sunburn, one way or another, even with the full restoration of the leaf part and the stem, will affect the crop.
With burns, the plant can be cured with mineral fertilizers. It is best to transplant the tomatoes in cloudy weather and make a shadow for them in the first few days. Harvest on burnt bushes will be several times less than on completely healthy ones.
What to do if symptoms have already appeared
If white spots have already appeared on the tomatoes, then several treatment options are considered:
- folk methods;
- chemical substances.
It is recommended to use the first two methods to start, and if there is no result, then switch to the use of fungicides. The thing is that any chemical preparation has toxins in its composition that the stem and the fruits themselves absorb. Eating fruits can be done only three weeks after processing, and fungicide treatment should not be carried out if the site is near a reservoir.
The agrotechnical method involves the removal of all plant residues after harvesting. The remains cannot be buried, they must be completely destroyed. Complete destruction of the affected bushes is the main method of combating white spots on tomato leaves. Crop care should also be reviewed. With fungal diseases, the main reasons are too warm weather and waterlogging of the soil. These reasons will be the same, both for plants grown in the greenhouse, and for those growing in the fresh air.
Unfortunately, most fungal spores can withstand temperature extremes and remain viable for a long time. The first step is to reduce the number of irrigations, up to once a week. In greenhouses, it is recommended to cover the soil between plants with dark polyethylene to prevent the spread of fungal spores through the soil mixture. It is advisable to water with a solution of potassium permanganate, as well as spray them themselves stems and leafy part. In combination with a manganese solution, a decoction of ash and iodine is used.
One of the effective folk remedies is watering with garlic broth. In the greenhouse, optimal air exchange should be established. If the reason is excessive moisture and stagnation of air, it is recommended to tie twigs, and lay cardboard under the bushes, try to irrigate without spraying water. For many fungal and infectious diseases, any treatment is useless, therefore, when the first symptoms are identified, it is recommended to completely eradicate all affected plants and treat healthy ones.
Not all tomato diseases can be treated. Most fungal infections are eliminated by the complete removal of the affected bushes, in order to avoid infection of neighboring healthy plants. After removing such crops, all instruments should be sanitized, and treatment should be carried out for healthy shoots.