What does macrosporiosis of tomatoes look like and why summer residents are so afraid of it: we get to know the enemy closer and win

Macrosporiosis of tomatoes is the cause of crop loss for many summer residents. This disease can affect the plant at any stage of development, starting from seedlings... To keep plantings healthy and get a rich harvest, you need to learn to recognize the pathogenic process at the initial stage. Check out the description of tomato macrosporiosis, photos with signs of the disease, methods of prevention and control.

What is this disease and how does it affect tomatoes

Macrosporiasis (dry spot) is a fungal infection of tomatoes. The disease develops, as a rule, on weakened plants due to lack of nutrients.

Macrosporiosis affects the stems, leaves and fruits of tomatoes. The disease can completely destroy plants and crops within two weeks. Fungal spores infect the soil, compromising the well-being of subsequent plantings.

Symptoms and external signs

At the initial stage, signs of damage are noticeable on the lower leaves: rounded dry brown spots with clear outlines and a characteristic concentric pattern appear. Gradually, the fungus spreads to the stems and upper leaves.

Infected stems have brown and slightly depressed elongated spots.Then comes the fruit. The lesion starts from a peduncle or a crack and spreads to the entire tomato in the form of dark brown, rounded, depressed spots. The structure of the fruit changes, it is no longer suitable for consumption.

Soon the disease covers the entire bush, individual lesion spots merge, the leaves dry up en masse and die off. While developing, the fungus begins to sporulate. At the same time, the spots acquire a velvety black coating.

Reasons for the appearance and infection

The cause of the disease is the penetration of microspores of a pathogenic fungus into plant cells. This occurs with mechanical damage to the stems and leaves. Immunity of tomatoes, weakened by pests and lack of necessary nutrition, does not resist the spread of infection. Hot and humid weather helps the development of macrosporiosis.

Causative agent of the disease

The causative agent-pathogen is a fungus of the class of imperfect Macrosporium solani Ellis. The best conditions for its germination are the presence of moisture in the form of drops and a temperature of 18-20 ° C. The incubation period is temperature dependent. At 22-24 ° C, it is 2-3 days, at elevated (30-32 ° C) or low (14-16 ° C) temperatures, it increases to 7-12 days.

Spores of the pathogen overwinter in the soil and on plant debris and remain viable for more than three years.

Terms of distribution

The causative agent of macrosporiosis is spread by wind and raindrops. Infection of tomato tissues occurs through the stomata of leaves and places of mechanical damage.
The disease develops especially rapidly in hot weather with heavy rainfall or dew. An increase in air temperature to 20-22 ° C and humidity to 80-90% always precedes the appearance of dry spotting on tomatoes.

How and what to treat

Despite its seriousness, macrosporiosis is treatable. There are many effective recipes in the arsenal of experienced gardeners.

Chemicals

At the first sign of dry spotting, you should immediately spray the tomato bushes with one of the following:

1. 0.4% copper oxychloride (oxychloride) solution: 40 g of the drug per 10 liters of water.To increase the adhesion of the solution to the leaves, it is recommended to add a little 1% milk. Solution consumption - no more than 1 liter per 10 m2.
2. 1% bordeaux liquid: Dissolve 100 g of copper sulfate and 100-150 g of slaked lime separately in 1 liter of hot water, bring each solution to 5 liters, strain the lime suspension and add a solution of copper sulfate. Consumption - 1.5-2 liters per 10 m2.
3. 0.4% cineb solution: Dilute 40 g of powder in 0.5 l of water, mix thoroughly, bring the volume to 10 l. Consumption of working solution is about 1 liter per 10 m2.

Complex fungicidal agents are also suitable for processing tomatoes: Polychom, Polykarbatsin, Ridomil. They should be used according to the instructions.

When working with all chemicals, safety requirements must be observed: use gloves and respirators, at the end of work wash your hands and wash clothes.

Spraying with chemicals is carried out 3-4 times per season.

Important! The use of fungicidal preparations should be stopped no later than three weeks before harvest.

Traditional methods

For those who prefer natural remedies, there are folk ways to combat macrosporiosis:

1. Infusion of garlic and hot pepper. Chop 200 g of garlic in a blender or meat grinder, add 3 liters of water and leave in a dark place for two days. Strain the infusion, add 0.5 teaspoon of ground hot red pepper. Spray the tomatoes with the resulting extract once every ten days.
2. Iodine solution... Dissolve 20 drops of iodine in 8 liters of water, add a little dishwashing liquid to improve the retention of the solution on the foliage. Spray tomatoes once a week if signs of fungal infection appear.
3. Infusion of mullein. Place 1 kg of rotted hay and 3 kg of fresh cow dung in a container. Pour 10 liters of water. Insist for three days. Then strain the infusion and process plants with signs of the disease 1-2 times a week.

Agrotechnical techniques

If macrosporiosis has significantly affected tomato bushes, you can try to save the crop. To do this, you need to remove the unaffected fruits and put them for ripening, having previously dipped them in hot (60 ° C)

Preventive measures

Prevention of any disease is easier than cure. The following set of measures will help prevent dry spotting:

1. Seed dressing - processing of planting material for the purpose of disinfection. The most accessible substance is potassium permanganate (potassium permanganate). To prepare a 1% solution, 1 g of the drug should be dissolved in 100 ml of water. Seeds soak tomatoes in the resulting liquid for 45 minutes, then rinse well with clean water.
2. Top dressing plants with microelements and pest control that weaken the protective functions of tomatoes.
3. Alternating landings so that the tomatoes are planted in the same area no earlier than two years later.
4. The location of the beds with tomatoes as far away as possible from other crops prone to macrosporiosis, such as potatoes.
5. Autumn soil disinfection bordeaux liquid or copper sulfate.
6. Ensuring good ventilation in order to avoid high humidity when growing tomatoes in a greenhouse.
7. Regular treatment of instruments with disinfectants or boiling water.
8. Burning crop residues after harvest.

Gardener tips

Dry spot attacks tomatoes at any stage of growth. Therefore, during the entire growing season, they need attention and care. To maintain their own protective functions, plants need watering, loosening the soil and feeding.

Even after successfully treating tomatoes for macrosporia, the soil in the greenhouse should be replaced. Sow mustard on an infected garden bed after harvesting tomato tops in early autumn.
If possible, it is better to give preference varietiesresistant to this disease.

Conclusion

Macrosporiasis is a serious fungal infection of tomatoes that can destroy the entire crop in a matter of days.The causative agent - the fungus is spread by the wind, affects all parts of the plant, loves a warm and humid environment. It is able to remain viable in soil for three years.

The disease is fought with the help of fungicides: traditional Bordeaux liquid, copper oxychloride and others. There are also a number of safe folk methods. The main preventive measure is maintaining the health and natural immunity of tomatoes. Seed dressing and reasonable crop rotation will help avoid contamination of the site.