Fight against late blight on tomatoes

Many gardeners who grow vegetables in their beds often encounter a plant disease such as late blight on tomatoes. To combat this disease of vegetable crops is appropriate and modern agrotechnical means, and folk techniques.

Fight against late blight on tomatoes

About the nature of late blight

The scientific name of late blight on tomato fruits and other vegetable crops is late blight. Some gardeners who do not have much experience in combating plant diseases may have never come across this name and do not even know what phytophthora is. However, they could see strange spots of black or brown on their vegetables. They look like foci and are present on the leaves of tomatoes and on the surface of the fruits themselves, penetrating the tissues and damaging the seeds. Phytophthora disease appears on infected tomato fruits when the leaves turn black, usually closer to the end of the gardening season, in late summer - before the fall. The harm from late blight lies in causing the inevitable death of tomato bushes under its action.

Without taking appropriate measures against phytophthora on tomatoes, you will have to accept the loss in harvesting a significant part of the future tomato crop with damage to the internal tissue and seeds. Torn affected by a fungus, the fruits are not eaten, their seeds can not be used for subsequent planting, because they are destroyed. Harvested vegetables, taken before their full maturation, are sent to ripen.

The causative agent of late blight on tomatoes and other vegetation with them is the fungus of the same name. It inflicts the most fatal effect on the nightshade family, and among the ones most often affected by this adverse disease are tomatoes.

Primary symptoms and contributing factors

The main signs of late blight on tomatoes during infection:

  • small foci of brown on tomato foliage on its reverse side,
  • a subsequent increase in the size of late blight lesions of the plant and the number of foliage and vegetables with them,
  • drying of tomato foliage and its falling,
  • the acquisition of shoots of tomatoes of a dark color shade,
  • the appearance on the surface of vegetable fruits of foci of a dark gray shade with their subsequent blackening.

Symptoms of late blight tomato disease appear most often in the second half of the summer season. This is due, first of all, to the peculiarities of this calendar period, when there is a difference between day and night temperature regimes, when there is no full heating of the soil, how much is enough for moisture to dry. Under the influence of temperature fluctuations, abundant dew forms on tomato bushes, which does not have time to dry out due to a decrease in the general air temperature, and becomes the most favorable environment for the appearance and development of late blight on tomatoes. Among the reasons where phytophthora appears on tomatoes:

  • persistent rainy days and the early coolness that came with them,
  • excess in the soil of the norm of the calcareous component,
  • excessive condensed planting of tomato bushes,
  • the absence of a well-functioning air circulation in the enclosed space, because phytophthora on tomatoes in a polycarbonate greenhouse often appears,

from which the fungus begins to develop with them even better and at an accelerated pace.

The development of late blight in tomatoes during the onset of heat and dry weather is slowed down. With an increase in temperature conditions to sufficient levels, you can completely get rid of it, since the fungal pathogen late blight dies.

Agrotechnical methods of struggle

For prevention, use some tricks.

Among the methods in the fight against late blight on tomatoes and for the prevention of late blight on tomatoes, experienced gardeners have long adapted to use a number of basic agricultural techniques that can prevent the disease and preserve the vegetable crop and a stable future crop. Good measures on how to deal with late blight on tomatoes and how to prevent late blight on tomatoes are:

  • compliance with the basic rules of crop rotation, which implies planting a vegetable crop after a change of place, adhering to the respite interval for 3-4 years, and prohibiting the planting of tomato bushes in the ground where potatoes, eggplants or peppers were previously grown, although the South Urals plant tomato seedlings after harvesting potatoes in a greenhouse and open soil, believing that the main thing is to warm and loosen the soil correctly,
  • reduction of tomato irrigation in excessively rainy and cloudy weather conditions, replacing this daily procedure with more frequent loosening of soil, carefully passing between the rows of land,
  • restoration of a good acid balance of soil in case of exceeding limestone standards, by adding an additional portion of the peat component, in the process of planting tomato seedlings in open ground or a greenhouse, it is sprinkled with sand from above,
  • the correct distribution of the density standard for planting tomato bushes, in accordance with the instructions for each individual tomato variety, avoiding their excessive thickening,
  • carrying out the main watering of the vegetable crop in the morning to ensure complete drying of moisture on the fruits and foliage by the onset of the night period, in which there is a significant decrease in temperature,
  • the use of predominantly drip irrigation, avoidance of water on the foliage when watering.

In order to prevent the occurrence of late blight on tomatoes, gardeners reviews recommend to grow and use those late-tolerant varieties and hybrids that are highly resistant, not afraid of late blight and resistant to other fungal diseases, for growing in regions cool in summer climatic conditions, for example, in the Moscow region.

To maintain tomato immunity throughout the entire gardening season, one should not forget to feed tomato bushes and process them with the help of immunomodulatory solutions.

In addition, the agrotechnical methods of gardeners in the prevention of late blight on tomatoes include the protection of vegetable crops by covering with a film or non-woven material. This is required, starting from the second half of the summer period, in the evening or in the period of prolonged rains. This will save your crop from unnecessary exposure to morning dew and will protect against the development of late blight.

Kitchen versus late blight

Those gardeners who are skeptical of fungicides and other chemicals and preparations for processing vegetable crops in order to destroy fungal diseases with them, are trying to find the most effective way for themselves to save tomatoes from late blight. Among the ways how to spray tomatoes from phytophthora and how to protect tomatoes from phytophthora are well-known folk remedies that lead to a positive result and allow you to cure plants when they become ill.


In order to carry out prophylaxis against late blight on tomatoes, many summer residents save sick seedlings and tomato bushes from danger in the greenhouse and in the open garden by means of a liter of fermented kefir or serum dissolved in a 10-liter bucket of water. In some cases, they add sugar to kefir in a small amount. Such milk prophylaxis of late blight on tomatoes is made and tomato bushes from late blight on tomatoes are processed weekly, and they begin to spray and wipe the bushes from the moment the ovary appears.

Yeast watering

Faced with the first signs of late blight on tomatoes, when the plants became ill, summer residents often try to defeat and prevent the development of a fungal disease by treating vegetables with simple baker's yeast. To do this, according to a simple recipe, fresh yeast (100 g) is dissolved in a liquid (10 l of water) and then planted infected plants with it. Some summer residents add mustard seeds to the yeast.


Phytophthora fungus will disappear after spraying with a mixture of garlic

Spraying tomatoes from late blight with impurities containing garlic helps to stop and treat tomato late blight disease, resulting in the death of late blight fungi under the influence of garlic. To spray tomato bushes, make a tincture of 1.5 glasses of finely chopped garlic heads and shoots and 10 l of water. The tincture of garlic is aged 24 hours, then filtered and 2gr of potassium permanganate is added there. Such tincture is recommended to spray tomato bushes with an interval of two weeks, it is possible a little more often. The fight against late blight on tomatoes from garlic suggests an approximate consumption rate for one bush of about half a liter.


Salt treatment is also a good tool than to treat tomatoes from late blight when the disease attacked. It is effective due to the formation of a protective film on the foliage of the salt, which prevents phytophthora from entering the plant. Although such a folk method is not intended for treatment, it acts as a good prophylaxis for affected plants. It is possible to spray 250g of water dissolved in a bucket with food or sea salt at the stage when there is already an ovary. Before processing, before spraying on green leaves, those damaged by late blight must first be removed and destroyed. Soda can be used with the same prophylactic effect.

Geology in the fight against late blight fungus

Considering folk remedies for late blight on tomatoes in the fight against late blight, gardeners often turn to natural components. But we must not forget that different varieties of tomatoes react to spraying and are susceptible to processing by folk methods in their own way. An important role in the effectiveness and choice of folk remedies, how to protect tomatoes from late blight, the weather also plays.


Among the popular folk remedies, how to deal with late blight and what to do with tomatoes in the prevention of late blight in tomatoes, simple ash received numerous positive reviews. Due to the content of many microelements in it, it acts as a full-fledged source of useful tools that help vegetable plants withstand tomatoes in the fight against late blight. The cooking technology according to the most popular recipe for an ash product includes several stages:

  • 5 liters of ash are dissolved in a 10 liter quantity of water,
  • the resulting mixture is thoroughly mixed and set for 3 days for infusion, with periodic stirring,
  • after the required time, the infused solution with ash is brought to a 30-liter volume,
  • soap is mixed in the solution (any one is suitable for this purpose, but the advice of experienced gardeners recommend an antibacterial household), the purpose of the presence of soap in the ash solution is to more efficiently stick the solution to the leaves in order to save tomatoes from late blight in a short time.

The resulting folk remedy with ash is required to spray tomato bushes. At the same time, it is recommended to process the vegetable culture with ash so that the treatment against fungal phytophthora on tomatoes is effective, it is recommended at least three times in one garden season. Initial spraying occurs when planting tomato seedlings in open ground or a greenhouse, after 10 days. Re-processing of greenhouse tomatoes or in the open ground from late blight falls into the flowering stage of the vegetable crop. The third spraying as a way to deal with late blight on tomatoes, occurs after the appearance of the ovaries.

Copper wire

Increasingly, reviews of summer residents are advised to use ordinary copper wire for the control and prevention of late blight in tomatoes. They believe that copper particles contained in an industrial product can neutralize late blight fungi. For this folk remedy against fungal disease, cut the wire into pieces up to 3-4 cm long. Each of them will have to be calcined, peeled, and then inserted into the tomato stem closer to its lower part. The ends of the wire, in order to avoid injury when caring for the bushes, are bent towards the bottom, but do not wrap themselves around the stem, giving it freedom of growth and development. There are many videos of gardeners on which you can see how to wire correctly from phytophthora on tomatoes.

Nature vs Tomato Phytophthora

Often, folk remedies for the control of late blight in tomatoes basically contain useful and protective properties of plants.

Tinder fungus

Tincture of tinder fungus will help in the fight against the disease

Mushroom tinder fungus acts as a good defender of vegetable crops against the appearance and development of fungal diseases of plants. Tinctures made on the basis of tinder fungus are intended for spraying tomato bushes. Their use allows you to increase the resistance of tomatoes to the destructive effects of late fungus, performing a protective function. The recipe for tincture with mushroom tinder is to pour 100g of chopped tinder and 1 liter of boiling water and insist until it cools. Strained through a bib or gauze solution is watered with tomato bushes. Tall plants should be tried to process from the very top to the bottom. Initial treatment occurs at the stage of the appearance of the ovaries, secondary spraying is done with the timing of the appearance of the first signs of late blight on tomatoes.


Horsetail decoctions help cope with late blight and grow undersized and tall, disease-prone tomatoes without fungus. Dry horsetail (100g) is boiled in a liter of water for half an hour - 40 minutes over low heat. The cooled broth is brought to a volume of 5 liters. Cooked horsetail broth requires spraying tomato bushes. Instead of dry horsetail, you can take fresh, then the norm costs per liter of water will be 150g.


A good way to prevent fungal disease of tomatoes is simple straw, on the basis of which a solution is made for watering or spraying. As the main organic component can be taken rotted hay, fresh grass. They are filled with a bucket (10 l) of water with the addition of a handful of urea and infused for at least 4-5 days, after which it is filtered.

Medicine against late blight

In the fight and prevention against late blight on tomatoes, some summer residents often use chemistry, fungicides and medications, on the basis of which they make folk remedies. Common treatment methods include iodine, potassium permanganate, furatsilin, boron, trichopolum, metronidazole and other drugs.

In the list of ready-made preparations from phytophthora for saving the crop from phytophthora and phytosporosis, farmayod and profit and well-known calcium chloride and Bordeaux mixture are better recommended. At the agrotechnical market there is a contact copper-containing fungicide Hom, which has proved itself among chemical agents against fungus.

Iodine solutions

Having antimicrobial properties, iodine is often taken by gardeners for use in the fight against various microbes, including fungi. There are many recipes for the preparation of iodine mixtures for tomatoes:

  • 9 liters of water will require a liter of milk with low fat content and 20 pipette drops of iodine,
  • in 8 l of water you can dilute 2 l of whey, 100 g of sugar, 15 pipette drops of iodine, you can use milk instead of whey,
  • 1 liter of whey with 40 pipette drops of iodine and a large spoon of hydrogen peroxide is dissolved in a 10-liter bucket.

All solutions prepared on the basis of medical iodine act for the external treatment of affected green plants. Using iodine solutions, you need to process all the foliage and stems of tomato bushes. Particular attention is paid to the underside of the leaves.


Boric acid has established itself as a folk remedy, than you can spray tomatoes and thereby help them resist against fungal disease blight. When sprayed with boric acid, it is dissolved in a bucket of hot water in a proportion of 10 g per 10 l, adding 30 pipette drops of iodine there. In some cases, boric acid and phytophthora iodine in an amount of 10 g of each component are added to a heated aqueous ash mixture (8 l per 2 l).

In another recipe, potassium permanganate (at the tip of a knife) and copper sulfate from phytophthora, which must be diluted in a bucket of water, act as additional components to boric acid (10g). Copper sulfate requires a small spoon. There, along with vitriol and potassium permanganate, it is recommended to put a small piece of laundry soap.


Sometimes, to resist against late blight on the fruits of tomatoes, gardeners resort to chemical drugs, among which the effect shows trichopolum better. A bucket of water will need 10 tablets. 15 ml of green stuff is mixed with them. With the whole mixture obtained, it is recommended to process the vegetable crop at the flowering stage and immediately at the first signs of late blight.


How to choose top dressing for the rapid growth of thuja
How to distinguish geese Linda from other birds
The best varieties of zucchini, or how to achieve the perfect harvest