Late blight of tomatoes
Late blight is a disease of plants caused by a mycelial unicellular parasite - late blight. Most often it affects plants representatives of the Solanaceae family: potato, eggplant, pepper, tomatoes, but can also attack other crops such as strawberries and buckwheat. Methods for combating tomato late blight, a description of treatment with drugs and folk remedies are collected in the material.
Read also: Potatoes: description of 73 best varieties (Photo & Video) + Feedback from gardeners
Description
The name of the fungus "phytophthora" in translation means "destroying plants." The disease can affect the whole plant in just 3 days, and the entire planting on the site - in 1.5–2 weeks. In the case of tomatoes, the disease is very dangerous, because it affects the plant during fruit ripening, when it is impossible to fight it.
Phytophthora may contain:
- on seeds
- in the ground
- on garden tools
- plant remains
- in the material from which is made greenhouse or greenhouse
late blight on leaves
The infection is transmitted mainly from potatoes. The spores of the fungus overwinter in the soil in a potato field or in tubers.
Favorable conditions for the active life of a unicellular microorganism:
- high air humidity
- low temperature
- soil with a high lime content
- unthinned planting where fresh air circulates poorly
- sudden temperature changes
- morning dews and frequent fogs
- weakened plants, in the care of which the rules of agricultural technology are not observed
Read also: Sea buckthorn: description, cultivation, useful properties and contraindications, treatment, preparations for the winter - a symphony of benefits and taste! (Photo Video) + Reviews signs
Manifestations of late blight
You can diagnose late blight on tomatoes by the following visible manifestations:
- Foliage has a white coating
- The lower part of the leaves darkens, covered with brown spots. Then the entire leaf plate turns black and dries. The plant sheds its leaves
- The stems of the plant darken, after a while they also dry out.
- Brown spots form on the fruits, the tomatoes become mummified or begin to rot. Brown streaks appear on harvested immature tomatoes for 1-2 days of storage
A characteristic symptom of fungal infection is that the spots can be gray or brown and usually have an irregular shape. Tomato fruits get sick through the stalk, so they can look healthy outwardly. Phytophthora spots appear even at the stage of tomato ripening.
Blackening of fruits is a symptom not only of late blight, but also the result of excessive watering, dry soil or an excess of fertilizers. Phytophthora is easily confused with other diseases on tomatoes - their distinguishing features are summarized in the table.
| External manifestation of the disease | Possible reason |
|---|---|
| Brown fruits and roots of tomato on the surface | The plant does not have enough moisture, it tries to absorb water from the air |
| black spots on tomatoes | Lack of minerals (boron, magnesium) |
| Brown spots appear on the bottom of the fruits, they rot inside | Blossom rot |
Read also: The best 46 varieties of tomatoes for a greenhouse: a description with a photo and reviews about them
Treatment
For the treatment of tomatoes from late blight, the following methods are used:
- Use of chemicals, biofungicides, antibiotics
- Spraying plants with folk remedies from available ingredients
- The use of mechanical means of protection
Industrial preparations
Fungicides for tomatoes
The most popular chemicals for fighting the fungus - fungicides and features of their use in the fight against late blight on tomatoes are collected in the table.
| Name | Recommended dosage per 10 liters of water | Application |
|---|---|---|
| Quadris | 10 g | Safe for people and animals, it is recommended to carry out up to 3 treatments per season, but no more than 2 times in a row. |
| Ridomil Gold | 25 g | 4 sprays are carried out per season: during the growth period, and then every 14 days, under favorable conditions for the fungus - 1 time per week. |
| Thanos | 12–13 g | The best remedy, according to many gardeners, forms a protective film on the leaf, suppresses pathogenic microorganisms and stops the disease. Sprayed during the growing season, and then 1 time in 10 days. |
| Topaz | 2 ml | It has a wide range of effects, is safe for humans and other plants. Processing is carried out every 10 days. |
| Speed | 20 g | Suitable for spraying, soaking seeds or cuttings. |
| Fundazol | 10 g | It is used to prevent and combat the first signs of the disease. The frequency of processing is every 10-12 days. |
| Acrobat MC | 40 g | Used to prevent or combat the first signs of the disease, repeat every 14 days. |
The fight is also carried out with the help of:
- Bordeaux liquid. Plants are sprayed with a 1% solution every 8–10 days until the fruits turn red. Stop processing 15 days before harvest
- Copper vitriol. Dissolve 50-60 g of the substance in 20 liters of water, spray the plants before flowering
When using fungicides, remember that phytophthora quickly adapts and develops immunity to a particular drug, so the chemicals need to be changed periodically.
Biofungicides
Biofungicide Fitosporin-M
To date, a new generation of microbiological preparations has also appeared, which include bacteria to fight the fungus. They are less effective than conventional chemicals, but much safer for humans.
The generic drug is Fitosporin - it spreads through the vascular system of the tomato and suppresses pathogenic microorganisms - fungi or viruses. The recommended dosage for spraying is 5 g per 10 liters of water.
The substance is used for soaking planting material, watering the roots and treating the soil before planting tomatoes. The frequency of processing tomatoes is 8–15 days, depending on the weather, climate and plant condition.
Antibiotics
Antibiotic Trichopol is considered an effective means of combating phytophthora. The active substance of this drug is metronidazole. For processing, it is necessary to use 5 tablets per half a bucket of water, spraying the planting 2 times a month.
Tablets are dissolved in a small amount of water, and then topped up with the main amount of liquid. Liquid soap is added to the solution so that the drug sticks to the foliage. Spraying should be started immediately - the solution is not stored.
The procedure is carried out in dry, calm weather without strong wind. Then the planting is left alone for at least 7 days, re-spraying is carried out no earlier than after 14-15 days. From the moment of the last spraying to the appearance of the first fruits, at least 21 days must pass.
Infected tomato bush
Process the stem and leaves, paying special attention to the lower part of the plant. If it rains immediately after treatment, spraying should be repeated the next day.
If you exceed the dosage, then there is a risk of burning tomato leaves. To treat the roots, 45–55 ml of the drug is poured under each bush.
You can also use a cheaper analogue of Trichopolum - Metronidazole. It is also used for prevention: dressing seeds, watering seedlings when picking. The dosage is higher than when using Trichopolum - 20 tablets per bucket of water. Liquid soap and brilliant green are added to the solution for additional disinfection.
Folk remedies
fruits affected by the fungus
Means for the treatment of fungal infection of plants can be prepared at home. The main advantage of such substances is their safety for humans and the possibility of processing tomatoes even after the appearance of fruits.
Experienced gardeners recommend such recipes for phytophthora at home:
- Spraying with garlic water. It is necessary to grind 100 g of garlic into gruel (you can not only fruits, but also leaves of the plant), pour 200 g of boiled water, let it brew. After 1 day, strain the infusion and add 1 g of potassium permanganate. Dissolve the mixture in 7-10 liters of water for spraying
- Iodine. It is used as an antimicrobial agent in the composition of a milky-iodine solution. For cooking use 15-25 drops of iodine and 1 liter of milk per 1 bucket of water
- Yeast. Dissolve 40 g of fresh yeast in 5 liters of warm water, stir and pour the solution over the tomato bushes that have been attacked by the fungus
- Milk serum. Cow's milk is diluted with water in equal proportions and the tomatoes are sprayed daily.
- Wood ash. For 5 liters of water, take 2.5-3 kg of crushed ash, mix thoroughly, leave for 1 day. Then the water is drained, leaving a residue, and 10 liters of new water are added along with 10 ml of liquid soap (in order for the preparation to “stick” to the leaves). Processing is carried out 3 times: after planting seedlings, before flowering and before the formation of the ovary
- Rotten hay or straw mixed with water in proportions of 1 to 10 and a handful of urea insist 4 days, then filter and use for spraying
Mechanical elimination methods
Piercing a stem of copper wire
In the case when the fungus struck the entire plant and no attempts were made to cure the disease in time, the only way out is remove the affected tomato from the site along with the root system.
Affected stems and leaves should not be thrown with the rest of the grass into the compost pit., otherwise, during subsequent feeding, the site will be re-infected. In such cases, damaged plants are disposed of by burning them, and tomato stalks are treated with a solution of calcium chloride.
Phytophthora lives in the ground at a depth of no more than 10–15 cm., therefore, deep digging in the fall will help get rid of the source of pathogens of the fungus.
Piercing the stem with copper wire will also help treat the plant for infection. It must first be calcined on fire, cleaned with fine sandpaper and cut into small pieces up to 5 cm long. Each copper twig is inserted into a tomato stem at a height of 12 cm from the ground level, the ends are bent down.
It is impossible to wrap the stem around the stem with copper wire. If desired, at the stage of planting seedlings, you can wrap the roots with copper - then the plant will have strong immunity not only to late blight, but also to other infections.
This method helps to enrich the plant with oxygen and normalize the level of chlorophyll in tomatoes.
Read also: Landscaping your site with your own hands - (130+ Photo Ideas & Videos) + Reviews Prevention
Spraying tomatoes
The disease is better prevented than later spend a lot of time and effort on its treatment, especially since preventive measures give good results.
If chemicals are used for prevention, then the first treatment must be carried out at the stage of ovary formation, and then it is carried out every decade. Another option to prevent infection is to water the tomatoes every other time with water with the addition of fungicides.
After the fruits have appeared on the plant, chemicals are not used, gardeners are switching to safe for humans means of protection and prevention. So, it is recommended to use:
- Rock salt mixed with water in the ratio of 100 g per 5 liters. Still green fruits are sprayed with this brine: salt forms an invisible protective film on them
- Weekly spraying with a solution of fermented kefir or fermented baked milk can be carried out (1 liter of dairy product per 10 liters of pure water)
- Spraying with infusion of garlic, nettle, onion, bird cherry leaves
Green tomatoes plucked for ripening can be subjected to heat treatment as a preventive measure: warm for 2-3 minutes at a temperature of 60 degrees. It is impossible to eat fruits affected by the fungus.
How to reduce the risk of infection
Tomatoes in the garden
Tips on how to reduce the likelihood of late blight infection of tomatoes:
- Planting material must be dressed or treated with fungicides before planting.
- Soil with excess lime content is fertilized with peat
- When planting tomato seedlings, calcined river sand is placed at the bottom of each hole.
- It is worth adhering to the basic principles of crop rotation: melon, carrots, cauliflower and beets are bad predecessors for planting tomatoes on the site.
- Thin out the planting in time so that air circulates around each plant
- The lower leaves on the stems of tomatoes should be removed, and the soil under planting should be mulched.
- Tomatoes should be watered in the early morning or late evening strictly under the stem to prevent splashing and moisture on the leaves.
- Be sure to loosen the aisles
- Watering should be reduced at high humidity
- To carry out top dressing of tomatoes with complex mineral mixtures, the introduction of which strengthens the immunity of plants
- Do not plant various representatives of the Solanaceae family nearby. If this is not possible, then plant rock plants between the beds for protection: peas, corn, beans
- You can re-plant tomatoes in the same place only after 4-5 years.
Read also: Perennial flowers (TOP 50 species): garden catalog for giving with photos and names | Video + Reviews
Greenhouse care
Tomatoes in a greenhouse
Tomatoes are often grown in greenhouses, where a special microclimate is created that does not contribute to the infection of vegetables by a fungus. In the greenhouse, tomatoes are reliably protected from phytophthora, because there are no temperature changes in it, dew or fog are not terrible.
However, the greenhouse must be regularly ventilated to ensure the supply of fresh air to the plants.
For greenhouse tomatoes, the danger is the so-called southern late blight, which differs from the usual one in that it first affects the root of the tomatoes.
The disease is clearly visible on seedlings: the fungus affects the root leg, creating brown constrictions on it. Seedlings break, rot and dry out. To combat this disease, seedlings are treated with a 1% solution of sodium humate. The reason for its occurrence is phytophthora spores in the untreated walls of the greenhouse.
To prevent the spread of the fungus, it is advised to start with sanitizing the walls of the greenhouse or greenhouse with fungicides, removing cobwebs, dirt, and plant debris.
You can also use the following methods of disinfection of the room:
- Fumigation with smoke from a piece of natural wool burning in a bucket of coals
- The use of tobacco-ash powder. To prepare it, take 400 g of tobacco dust and 7 kg of wood ash, crushed to a powder.
- Using drugs Fitosporin or Baikal EM
It is better to change the entire soil in the greenhouse, but you can get by with only the top layer of soil. You can bury the seeds of marigolds, mustard or dill in the ground for fertilizer and treatment.
Preventive spraying of tomatoes in the greenhouse occurs with the same frequency as in the open field: after rooting of seedlings, before the appearance of the first flowers and first fruits.
In autumn, the earth is dug up, removing all the remains of plants, dried tomato stalks are pulled out along with the roots and burned. In this case, the subcortex of the soil with complex mineral mixtures will become a mandatory measure of agricultural technology.
Read also: Projects of country houses for 6-10 acres: 120 photos, description and requirements | The most interesting ideas Resistant varieties and hybrids
tall tomatoes
There are no varieties that are 100% protected from phytophthora infection. At the same time, early varieties that give a harvest before August, and specially bred hybrids, show high resistance to phytophthora.
Resistant varieties
Low-growing early ripe varieties of tomatoes
Varieties of tomatoes with increased resistance to the fungus are collected in the table.
| Characteristic | Name | Peculiarities |
|---|---|---|
| Undersized varieties | Oak | The height of the stem does not exceed 50–60 cm, the weight of round red fruits is not more than 90–100 g. It is characterized by high yield. |
| Dwarf | An early ripe plant with a stem height of 40–45 cm and round fruits. The yield is up to 3 kg per bush. | |
| Tall varieties | Resonance | Large fruits weighing up to 250 g tolerate transportation well. |
| orange miracle | Mid-season tomato, the fruits of which ripen 80–85 days after planting. Tomatoes reach a weight of 400 g, slightly flattened, orange in color. The variety tolerates heat and drought well. | |
| Early | Perseus | The stems grow up to 75 cm, the fruits are small (up to 150 g), bright red in color, they tolerate long-term storage and transportation over long distances. |
| Lights of Moscow | The fruits are dense, weighing no more than 230–250 g, suitable for storage and transportation. | |
| Mid-season | Academician Sakharov | Salad variety, fruit weight - up to 300 g. |
| orange giant | Fruits are orange in color with a high content of carotene, large and fleshy. | |
| Greenhouse | Tatyana | Mid-season tomato, reaches a height of 60 cm, the fruits are fleshy, red, weighing up to 150 g. A high yield is characteristic - 8 kg per plant. |
| Cardinal | A tall variety (up to 2 m in height), bears fruit 75–80 days after planting. Raspberry tomatoes, massive (up to 0.8 kg), flattened. | |
| Carlson | Productivity - up to 9-10 kg from 1 bush, the fruits are small, elongated, weighing up to 250 g. |
hybrids
Hybrid varieties resistant to fungus
Hybrid varieties bred by breeders have increased immunity to various diseases, including the late blight fungus. The following hybrids have gained popularity among gardeners:
- Soyuz-8 F1. An early ripe variety that has the best resistance to late blight pathogens
- Lark F1. Ultra-early variety with a high degree of setting. The fruits are red, rounded, without a green spot at the stem. Productivity reaches 10 kg per bush
- New Year's F1. Against the fungus, not only the plant is stable, but also its fruits during storage.
- La-la-fa F1. The fruits are large, bright red, stored for up to 2 months
late blight - an insidious and dangerous disease for plants, but knowing its first signs and taking preventive measures of protection, damage can be avoided. Tomatoes, like other nightshades, are saved with the help of fungicides - natural and chemically synthesized. Another way to forget about the dodgy phytophthora is to plant varieties and hybrids of tomatoesdisease resistant.
How to prevent the infection of nightshade phytophthora, what to do if the disease has already affected the plant, tells in training short videos:
VIDEO: PHYTOPHTHOROSIS - The epidemic has begun! We process tomatoes, cucumbers from late blight with me!
Late blight of tomatoes: a description of the signs, treatment of the fungus with fungicides, antibiotics and folk remedies (15 Photos & Videos) + Reviews
This article is very relevant for me, since I grow tomatoes in my summer cottage every year, I have also encountered late blight. It is very disappointing when dark spots appear on the fruits, so I want to thoroughly understand how to deal with this phenomenon. After reading the article, I concluded: in no case should tomato seedlings be planted after potatoes, this is an unsuitable predecessor. However, I have made this mistake before. I usually “save” my tomatoes by picking them while they are still green. And of course, I immediately remove those affected by phytophthora from the bushes. You also need to know what preparations can be used for processing, thanks for the information. In the photo, such a crop is just a feast for the eyes!
I agree - it is difficult to deal with phytophthora, but it is possible. If you strictly follow the rules for tillage, seeds, crops, as well as choose varieties that are resistant to fungal diseases, then late blight will no longer seem like a “terrible beast”. My family struggled with it for several years - they tried, probably, all the methods listed in the article, but we won. You need to start with soil preparation (since the spores of the fungus live there - after harvesting, it must be shed with a solution of copper sulfate or Topaz preparation. It is good if it is possible to sow the soil with white mustard, and then plant it in the soil and spill it with an EM preparation. Seeds before sowing, it is imperative to pickle in a strong solution of manganese.During cultivation, it is imperative to remove the leaves and mulch the soil so that no drops of water fall from it when watering.Well, if the plants still get sick, you must immediately treat both them and the soil with the preparation Topaz (I consider it the best of all listed) and do not waste time on “folk” methods - they are absolutely useless.