Late blight is one of the most dangerous and common tomato diseases. In order not to lose their crops, gardeners use a variety of methods. We will learn about the most effective means of combating the disease that can destroy up to 80% of the crop.
What is late blight?
Late blight or late blight is a common fungal disease that affects about fifty garden crops. Tomatoes suffer more than other vegetables. The fungus spreads by spores, it is able to quickly and massively infect tomato plantations. A couple of days is enough for all the bushes to be infected.
The fungus affects the fruits and leaves of bushes, which leads to a significant decrease in yield. For the time being, the pathogen hides in the ground. It becomes more active only in the second half of July, when summer nights become damp and cooler.
How does the disease manifest itself on tomatoes?
The presence of late blight on plants can be guessed by the characteristic symptoms. True, when signs of the disease appear, crop losses cannot be avoided.
Phytophthora symptoms:
- fruits are covered with black or gray-brown spots;
- later affected fruits rot and give off an unpleasant odor;
- dark spots first appear on the leaves, then they dry and fall off;
- brown spots appear on the stems;
- during the rain, the leaves of the bushes affected by late blight become shiny, oily;
- tomato flowers become dark, dry up and fall off.
Reasons for the appearance
The main factor contributing to the appearance of late blight is high humidity. If it rains in the summer, phytophthora begins to spread rapidly. This is a disease of "mass destruction", it affects almost all tomato bushes, leading to very large crop losses.
Other reasons for the spread of late blight:
- thickened planting and poor ventilation;
- planting next to potatoes - most often it is he who first gets sick with late blight;
- significant discrepancy between day and night temperatures;
- copious morning dew;
- low daytime temperatures;
- excessive watering in the second half of summer;
- sprinkling irrigation;
- overdose of nitrogen;
- excess lime in the soil;
- lack of manganese, iodine, copper, potassium in the soil.
Fungus - the causative agent of late blight can spread in the wind, water, through garden tools.
Treatment with chemicals
Chemicals are highly effective and are usually used when signs of illness appear. Their minus is toxicity and the ability to accumulate in soil and fruits.
Fitosporin
It is a biofungicide with antifungal and antibacterial action. The drug contains hay bacillus - this is a natural enemy of the late blight pathogen.
The effect of using Fitosporin:
- inhibits the spread of late blight;
- helps to improve the condition of the soil;
- treated leaves and shoots are covered with a protective film that prevents bacteria and fungi from attacking.
The drug can be used at different stages - during seed treatment, when transplanting seedlings, during the lesion period. Fitosporin solution is used to treat not only tomato plantations, but also the soil in tomato rows, gardening tools, dry tops removed for laying in a compost pit.
How to use Fitosporin:
- after the first treatment, re-spraying is carried out - about a week later;
- it is recommended to water the soil with Fitosporin solution once a month;
- for prevention, foliage is sprayed if unfavorable weather conditions are created.
Dosage for spraying - 3 tsp. on a bucket of water. For better adhesion, it is recommended to add 1 tbsp to the solution. liquid soap.
Hom
The preparation HOM is a fungicide based on copper oxychloride. It is a light green powdery product, insoluble in water. HOM is a part of many combined fungicides - Ordan, Kuprolux, Homoxil and others.
The drug has a prophylactic and protective effect. It protects plants from fungus from the moment of spore germination until late blight symptoms appear. If signs of disease appear on the bushes, spraying with HOM will no longer be enough, an additional systemic fungicide is needed.
Features of the use of HOM:
- The drug is effective before the onset of the disease. If the leaves have started to turn brown, it is too late to apply HOM.
- It is allowed to use HOM no more than 4 times during the season.
- An interval of 10 days should be observed between sprays. This frequency is justified given the high risk of infection and in rainy summers.
How to prepare and apply HOM solution:
- Dissolve 40 g of dry preparation or 50 g of suspension in 1 liter of water.
- Mix thoroughly and bring to 10 liters.
- Spray the bushes with the finished composition - 1-1.5 liters for every 10 sq. m of tomato plantation.
- It is necessary to spray the leaves not only from above, but also from below.
The HOM solution should not drain from the bushes into the soil. This can provoke the oppression of beneficial soil fauna, such as earthworms.
HOM is cheap, non-phytotoxic, and does not accumulate in fruits and soil. The disadvantages of the drug include a short period of protection, washing off by rain and a large amount of solution that must be prepared for treatments. HOM provokes corrosion of metal products.
Ordan
The powdered domestic preparation Ordan is used for the treatment and prevention of late blight and other fungal diseases. In the composition - copper oxychloride and cymoxanil. The first component has an external impact, the second - internal.
Ordan oppresses and destroys various pathogens, heals infected areas, and has a complex effect. Pathogens do not have resistance to this drug. Ordan is low-toxic and is completely removed from the soil during the season.
Features of using Ordan:
- the drug is used at all stages of tomato development, except for flowering - so as not to poison the bees;
- the treatment is not carried out in sunny weather, so as not to cause burns;
- it is prohibited to carry out processing of wet plants;
- the maximum number of sprays per season is 2-3;
- the consumption rate in the open field is 80 ml of working solution per 1 sq. m
How to prepare and use Ordan's solution:
- Dissolve 50 g of powder in a bucket of water.
- Spray the leaves and stems on the day the solution is prepared.
Ridomil Gold
This systemic contact fungicide is Swiss made. Contains two active ingredients - mancozeb and mefenoxam, respectively for external and internal protection. The drug affects a wide range of pathogens and does not allow relapse. It is effective in running stages, does not burn, does not freeze, does not precipitate.
Cons of Ridomil Gold:
- expensive;
- toxic;
- high consumption for 1 sq. m;
- accumulates in the ground;
- kills beneficial fungi in the soil.
How to prepare and use the solution:
- Dissolve 50 g of powder in 5 liters of water.
- Mix thoroughly.
- Add up to 10 liters and spray the beds in the morning - if there is no dew, or in the evening.
- Use the prepared solution within 2-3 hours.
Thanos
Thanos is a contact systemic fungicide intended for the prevention and treatment of fungal diseases. Contains two active ingredients - cymoxanil and famoxadone. The first substance has a triple effect - heals, prevents and protects, the second - kills fungal spores.
Water-soluble granules do not freeze or crystallize, do not dust and dissolve perfectly in water. The drug has a wide spectrum of action, in addition to phytophthora, it saves tomatoes from phomosis, mildew, various rot and other diseases.
Thanos advantages:
- combined action;
- does not accumulate in fruits and soil;
- economical;
- fast-acting;
- convenient form of release.
Thanos has no flaws. The main thing is to observe the dosage and follow the instructions.
How to prepare the solution:
- dissolve the drug according to the dosage indicated on the package;
- pour the compound into the sprayer tank and add water.
The protection is effective for two weeks. During the season, the drug is used up to 4 times. The minimum interval between treatments is 15 days. The first spraying is recommended 2 weeks after transplanting.
Traditional methods against phytophthora
Admirers of natural farming successfully replace chemical preparations with various folk remedies. Their plus is absolute harmlessness to humans, minus is the need for regular treatments.
Here are some of them:
- Salt. The salt solution, getting on the aerial parts of the plant, covers them with a thin protective layer that prevents the penetration of fungi into the plant tissues. The saline solution is a prophylactic agent that only provides external protection to the plant. Prepare a solution by diluting 250 g of salt in 10 liters of water.
- Soda. 1 tbsp. Dissolve soda in a bucket of water. To prevent the solution from dripping from the leaves to the ground, add liquid soap to it - 1-2 tbsp. Thanks to the detergent, the composition will "stick" to leaves and shoots. Spraying is carried out at a frequency of 1 week, as well as after every rain.
- Kefir or whey. This method is based on the ability of lactic acid bacteria to suppress fungi and other pathogenic flora. It is used for prophylactic and therapeutic purposes. Dilute whey / kefir in water in a ratio of 1: 1/1: 10. If there is no kefir, you can replace it with milk. For 1 liter of milk, add 20 drops of iodine and dilute it in the same way as kefir. Dairy processing can be done daily.
- Ash. Dissolve 5 kg of wood ash in a bucket of water. Insist for 3 days, stirring the ash solution from time to time. Bring up the volume to 30 liters, add a couple of tablespoons of liquid soap and spray the tomatoes every week.
- Hay. The method is based on the ability of the hay bacillus to prevent the development of the pathogen. Take 1 kg of rotted hay, pour a bucket of warm water. Add 100 g of urea and leave for 3 days.
- Hot water. The advantage of the method is its low cost. Bring the water to a boil, let it cool slightly, and pour it into a rain showerhead. Water the soil with hot water so that the water does not get on the plants. Watering frequency - once a week.
- Yeast. They are used as follows: dilute 100 g of yeast in 10 liters of warm water. Insist 1-2 days and spray the bushes.
- Vinegar. Dissolve 1/2 cup 9% vinegar in 10 liters of water. Spray the entire aerial portion of the tomatoes. Alternate vinegar treatments with other folk remedies.
- Garlic tincture. Garlic tincture is versatile, it repels pests and protects plants from bacteria and fungi at the same time. Grind the garlic arrows and heads in a meat grinder. Pour 1.5 cups of raw materials with a bucket of water and leave for 24 hours. Spray the tomatoes every half month.
Pharmacy preparations
It turns out that pharmaceutical preparations help not only people. Many inexpensive and popular drugs sold in pharmacies can protect plants from late blight and many other diseases.
Furacilin
This cheap antibacterial and antifungal agent suppresses the development of fungal spores and destroys disease-causing fungi. Conveniently, the working solution can be prepared for the entire season to be used as needed. To prevent the solution from losing its properties, it must be stored in a dark place.
Preparation of furacilin solution:
- Crush 10 tablets. If you throw them whole in water, they will dissolve for a very long time.
- Pour the resulting powder with hot water.
- When all the particles have dissolved, bring the volume up to 10 liters.
When preparing a solution of furacilin, only non-chlorinated water is used.
Metronidazole (Trichopolum)
The drug fights against anaerobic flora and all sorts of protozoan microorganisms. It is also effective in the fight against fungal infections.
How to prepare the solution:
- Dissolve 20 tablets in 1 liter of water.
- Stir and pour into a bucket. Bring up the volume to 10 liters.
- Add liquid soap. To enhance the effect, you can pour in a bubble of brilliant green.
Do not store the solution, it must be used within a few hours. It is recommended to repeat the spraying the next day.
Iodine
Iodine is both a top dressing and an effective antiseptic. It is often used in combination with other products - added to milk, kefir, ash solution.
Application of iodine:
- Dilute 20 drops of the preparation in a bucket of water.
- Spray the tomatoes with this solution.
- Open the iodine vials and arrange them around the greenhouse. Iodine vapors will help to strengthen the immunity of the seedlings.
Boric acid
The drug has antiseptic and insecticidal properties. It is used to protect plants from late blight, as well as in case of boron deficiency. Spraying with boron improves the formation of ovaries and strengthens tomato bushes, accelerates the ripening of fruits. The drug is used both for spraying and for watering.
How to prepare the solution:
- Pour 1 tsp boric acid into a bucket of water. Water temperature - + 50 ... + 55 ° С.
- Use when the crystals are completely dissolved, otherwise the above-ground part may be burned.
Calcium chloride
This drug is a food additive and has detoxifying properties. He is able to save the fruits of tomatoes when the leaves of the bushes are already affected. For spraying, use a 1% solution.
How to prepare and apply the solution:
- Buy a 10% calcium chloride solution from a pharmacy and dilute it in 2 liters of water.
- Add some liquid soap for a sticky effect.
- Spray the bushes. Treat the stalks especially carefully.
Processing is carried out before flowering - for prophylaxis, and when signs of late blight appear.
Zelenka
Zelenka is an excellent antiseptic that can kill fungal infections. It is recommended to alternate brilliant green with iodine, boric acid and manganese. Prepare a solution by diluting 40 drops of brilliant green in a bucket of water. They are sprayed with tomatoes for preventive and medicinal purposes.
Hydrogen peroxide
This popular antiseptic not only kills pathogens but also oxygenates plants. Peroxide solution can be used for seed treatment, spraying and watering the soil.
How to prepare and apply the solution:
- In 1 liter of warm water, dilute 2 tbsp. l
- The solution is unstable, so start spraying the tomatoes immediately.
Potassium permanganate
Potassium permanganate is an antiseptic that is actively used at all stages of plant vegetation. They disinfect not only seeds, but also the soil. Also, a solution of potassium permanganate has shown itself as an effective antifungal agent. Prepare a solution by diluting 1 g of the drug in a bucket of water.
Other methods
Along with fungicides and folk remedies, other methods are used to combat late blight. The advantages of alternative methods are simplicity, low cost and efficiency.
Bordeaux mixture
This popular remedy is a mixture of quicklime and copper sulfate. The prepared solution is sprayed only on the affected parts of the plants. Four treatments are carried out per season. The intervals between spraying are 7-12 days.
How to prepare and apply the solution:
- Mix 100 g of copper sulfate and 150 g of lime (quicklime) in a bucket of warm water. Follow the sequence of actions - first dissolve vitriol, then lime.
- Spray tomatoes using protective equipment. The weather should be clear and calm. The optimal time is morning and evening. The consumption rate is 1 liter of solution per 5 sq. m
It is forbidden to prepare the Bordeaux mixture solution in a metal container. We recommend using plastic, glass or wood dishes.
Copper sulfate
This versatile and inexpensive remedy has antimicrobial and antifungal effects and helps against a wide variety of diseases.Practical experience shows that the remedy effectively prevents late blight.
Benefits of copper sulfate:
- suitable for different cultures;
- kills spores on plants and in the ground;
- considered a low-hazard substance;
- it is partly a fertilizer, since it contains copper, which is necessary for the vital activity of cells.
Lack of copper leads to inhibition of the development of tomatoes - they do not form ovaries and fruits, and the leaves turn brown and die off.
Dosage, g / 10 l:
- for soaking seeds - 1;
- for spraying bushes - 10;
- for soil disinfection - 100.
How to prepare 1% watering solution:
- Dissolve 100 g of powder in 1 liter of warm water heated to + 40 ° C.
- Make a blue solution in a bucket with 9 L of water.
- If the crystals are not completely dissolved, strain the solution through a piece of gauze.
- Use the composition within 9 hours. The next day, the solution will be ineffective.
Mulching
Mulching is a universal agricultural technique that allows you to achieve several goals at once. You can use peat or compost for mulch.
Mulching effect:
- preventing the soil from drying out;
- exclusion of excessive watering;
- protection against fungi that live in the soil.
Mulching is especially necessary when planting tomatoes without tying up, when the bushes are partially in contact with the ground. If you do not add a layer of mulch, the pathogen, rising through the leaves in contact with the soil, penetrates the stem. If this happened, then the phytophthora cannot be stopped. All that remains is to collect the fruits and put them for ripening.
Use of copper wire
Phytophthora fungi are extremely sensitive to all copper-containing drugs. They are afraid of copper in any form and form. This is the basis of the next way to combat late blight. For this, you need a coil of thin copper wire.
Procedure:
- Wrap the wire around the stems of the tomatoes at the root collar.
- Cut a piece of wire about 3-5 cm long and pierce the stem at the base with it. Bend the ends of the wire to the ground.
This method can only be applied to well-developed bushes. Otherwise, you can destroy the plants.
Plant processing rules
In order for the effect of the drugs used against late blight to be maximized, certain rules must be observed:
- spray treatment is carried out only on calm and sunny days;
- when using toxic drugs, it is necessary to wear protective equipment;
- it is forbidden to prepare chemical and some other solutions in metal dishes to avoid oxidation.
Late blight-resistant varieties
Planting varieties resistant to late blight is one of the most effective methods of preventing this disease. Unfortunately, there are no tomatoes that would have absolute immunity to late blight. But there are varieties that resist this disease better than others. These are mainly early maturing hybrids.
The varieties resistant to late blight include Blizzard, Budenovka, Yagodka, Dubrava, De Barao, as well as hybrids Otradny, Grotto, Lark and others.
Prevention of late blight on tomatoes
Preventive protection of tomatoes from late blight is primarily in the observance of agricultural technology. Measures to prevent fungal infection of tomato plantings depend on where they are grown - in a greenhouse or in an open field. In both cases, it is necessary to process the seeds by placing them in a potassium permanganate solution for 30 minutes before sowing.
In the greenhouse
The greenhouse has ideal conditions not only for plants, but also for pathogens - fungi, bacteria and other infections. The causative agent of phytophthora actively develops in moist stagnant air, which often reigns in greenhouses.
Preventive measures:
- If the greenhouse / greenhouse is not used for the first year, cleaning and disinfection is necessary.
- The room is cleaned of cobwebs and plant debris.
- In the greenhouse, the soil is completely changed.
- Disinfection is carried out using different methods. One of the simplest and most effective is fumigation. A metal container filled with glowing coals is brought into the greenhouse. Woolen fabric is placed on top of them. The room is fumigated for 24 hours. The second option is spraying with disinfectants, Fitosporin or Baikal.
- When planting seedlings, sprinkle with tobacco dust or wood ash.
- Airing the greenhouse, preventing condensation.
In the open field
Prevention of late blight in the open field requires an integrated approach. It is necessary to comply with irrigation norms, crop rotation and other rules of agricultural technology.
Preventive measures:
- Soil deoxidation by adding lime. To restore normal soil acidity, it is necessary to add peat for digging.
- When planting seedlings, dry sand is thrown into each hole - about 3 tbsp. l
- In the area where onions, potatoes, beets, cucumbers or carrots grew, tomatoes are not planted for at least 3 years.
- The plot for tomatoes is chosen sunny, without stagnant water.
- Watering - in the morning or late in the evening, at the root. If summer is wet, watering is canceled.
- The soil is loosened regularly to provide air access to the roots.
Possible mistakes in the fight against late blight
Despite the abundance of means and methods to combat late blight, this disease appears in many gardens every summer. The cause of the disease is often gross mistakes made by gardeners.
Common mistakes:
- The use of sprinkling when watering the beds. Tomatoes can only be watered at the root. The optimal method of soil moistening is drip irrigation.
- Incorrect feeding. In order for tomatoes to successfully resist the pathogen of late blight, they must be fed with potassium-phosphorus fertilizers. You can not abuse nitrogen fertilizing.
- Watering during illness. If late blight has already appeared on the tomato plantation, watering them is strictly prohibited. Increased humidity will only increase the development of pathogens.
- Application of several methods. You cannot use different methods of struggle at the same time. It is especially harmful to combine chemicals. Plants die from an excess of "chemistry", and their fruits accumulate a critical amount of poisons.
Despite the destructiveness of late blight for tomatoes, it can be successfully dealt with. There are dozens of simple and effective ways to not only treat this fungal infection, but also prevent it.
Author of the publication
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Russia. City Novosibirsk
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