How to treat yellow spots on tomato leaves
Yellow spots on tomato leaves, a common occurrence in the practice of a vegetable grower. If such a deviation is observed on plants, it is urgent to deal with them. Spots lower the yield, or even destroy it.
Tomato yellow spot treatment
Different rashes, spotting are the most popular problems that arise, regardless of where the tomato was grown. Often - this is caused by a disease or growing conditions, but in order to start treatment, you need to understand and make the correct diagnosis.
Reasons for the appearance
Causes of occurrence: temperature, humidity, disease, root damage, fertilizing in large quantities or lack of nutrients.
All diseases of tomatoes, do in groups:
- viral - mosaic, curl (coagulation) of foliage;
- fungal - gray rot, septeriosis, late blight, powdery mildew, mold (cladosporiosis), fusaiores and others;
- bacterial - cancer.
Curl or coagulation of leaves
A disease that has its roots in the southeastern regions of the United States and northern Mexico.
Signs - fabrics turn yellow, curl and curl of leaves, older ones are covered with purple.
A viral disease is transmitted by small insects - whiteflies. A flying insect picks up a virus from a host plant (peppers, tomatoes, beans, weeds) and transfers to healthy ones. A large infection occurs when the number of whiteflies is high.
Treatment with insecticides in order to reduce the population of whiteflies is not always effective; spraying the solution lacks the lower parts of the foliage, where a large number of insects live. It is recommended to remove the infected plants and the introduction of fallow. This will reduce the ability of whiteflies to develop pesticide resistance.
The virus enters plants with sap, using aphids (insects) or through agrotechnical processing methods. The virus remains on the inventory, seeds, tools, plant debris, or in the soil for 2 years.
Symptoms of the disease may vary depending on the age of the plant, the type of virus, variety, growing conditions. Yellow spots or mosaic appear, deformation and necrosis of organs, leaves.
Extract of seeds in an incubator at a temperature of 70 degrees for 2-4 days. The cross-protection method is the grafting of a mild form of the virus to a plant; subsequently it generates the plant's resistance to different types of virus.
Infected plants must be removed from the site.
With the help of bleach, tools are treated - they are disinfected. Observe the site and timely clean infected plants, clean the ridge of plant debris - to prevent the spread of infection.
If the leaves are already covered with a mosaic, it is necessary to spray with low-fat milk. A liter of milk is diluted in ten liters of water (room temperature), and one tablespoon of urea is added. Spraying is done once a week until the disease goes away.
Appears on plants, if you do not control watering and humidity in the greenhouse, plant tomatoes on non-sterile soil, sow untreated seeds.
Signs - at first the disease spreads along the stem in the form of gray-brown spots. Gradually captures the entire stem. Then the hue brightens and streaks appear. Due to the defeat of the stem, plant nutrition stops. Leaves above turn yellow.
The main protective method is to control the humidity in the greenhouse, it is necessary to keep it not high. Protect from mechanical damage during the collection and care of the tomato.
When spots appear, you need to brush them with a paste, which contains fungicides - copper sulfate, copper chlorine (HOM), Bordeaux liquid and others.
Signs - the bottom of the leaf is covered with yellow spots, the leaves fall away. The fruits turn black.
There are many means of combating late blight, they all act on the same principle. It is recommended to alternate chemicals - this will give an effective result. Tomatoes are sprayed with solutions: kefir, salted, garlic, cindery, tinder, milk - iodide and others.
The disease is spread by spores. The plant dries, wrinkles, turns brown and dies. Yellow spots on tomato leaves in a greenhouse are most often caused by this fungus.
Signs - first the leaves of the lower tier are yellow, then the whole plant. At the initial stage of the disease, the tomato is covered with yellow, and then red - brown shades.
A number of agrotechnical methods are being carried out that contribute to the destruction of the fungus in the soil. It is necessary to remove plant debris in a timely manner, steam and disinfect the soil, ventilate greenhouses and greenhouses, choose a stable type of tomato.
At the first sign of illness, plants need to be sprayed
Affected plants are sprayed with fungicides (once every two weeks). It is recommended to spray during the growing season. Mechanical methods are supplemented with chemical preparations - HOM, Abiga-Peak, Pram. Processing is carried out in the evening or in the morning.
Signs - the plant acquires a pale green or yellow color, tomato sprouts wither, the upper parts are deformed, twist and fall, the roots die. High fever intensifies symptoms.
If you have a sign of Fusarium, this is a doomed plant. The best you can do is clean the plant and sanitize the place.
Preventive methods provide reliable protection for your crop:
- it is necessary to check the seedlings;
- use sterile instruments;
- when the fruits are formed, we apply only potash fertilizers;
- disinfect seedling roots;
- sow in warm soil.
In the former Soviet Union, a bacterial disease appeared in 1936, in the form of infected seeds.
Tomato cancer is caused by bacteria. Signs of development - greens begin to fade, a yellow line appears along the contour. On young stalks, sepals and petioles, red and brown ulcers appear.
The plant at the stage of vegetation is treated with drugs that include copper. Spray with the antibiotic Fitolavin. Medicines with chitosan and humate will help.
A tomato may become covered with yellow leaves, not only due to illness. A common cause is root damage. Damage of a mechanical nature caused by careless loosening of soil near a tomato. The leaves of the lower tier begin to turn yellow.
The root system of tomatoes has a good recovery, so this goes away on its own. It is recommended to pour soil near the plant with fertilizer of organic origin.
Another reason is poor-quality fertilizer or lack of it. Any plant, including tomatoes, change their color if they lack copper, iron, manganese or sulfur. Yellowing of greenery may indicate nitrogen starvation. As a result of a lack of magnesium - the tomato will cover with yellow pigments.
Tomato leaves can be covered with yellow spots for many reasons: various diseases, temperature, climate, humidity, lack of fertilizer. It is necessary to carry out preventive methods of processing plants. Timely handle pests. It is important to regulate the humidity in the greenhouse and do ventilation. Vegetable growers recommend processing the seeds, adhering to the rules of care, conducting pest control of the soil and tools, and you will get a rich harvest.