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Late blight called the plague of tomatoes, the most terrible disease of nightshades, it is from this disease that the entire tomato crop can die. How many tomatoes are cultivated by gardeners, so much their "war" with late blight lasts. For decades, farmers have come up with new ways to combat the causative agent of tomato disease, there are a variety of remedies for this disease: from the use of drugs to completely exotic methods, like copper wire on the roots of tomatoes or spraying bushes with fresh milk.
What is late blight, how can you cope with it and what provokes this disease? And, most importantly, are there varieties of tomatoes that are resistant to late blight - these issues are discussed in this article.
Why late blight is dangerous for tomatoes and what provokes it
Late blight is a disease of plants of the Solanaceae family, which excites the fungus of the same name. The disease manifests itself in the form of watery spots on the leaves of tomatoes, which quickly darken, acquiring a brown color.
The fungus quickly spreads throughout the plant, following the leaves, the stems are infected, and then the fruits of the tomatoes. Late blight of the fetus manifests itself as a thickening under the tomato skin, which darkens and becomes more and more. As a result, all or most of the fruit turns into a deformed brown substance with an unpleasant putrid odor.
The danger of late blight lies in the excessive vitality of fungal spores and their very rapid spread. In a few weeks, the entire harvest of the gardener can die, sometimes no way to combat this disease is effective.
The environment in which spores are stored and reproduced is soil. Late blight is not afraid of extreme heat or low winter temperatures - the contaminated soil in the new season will again contain spores and pose a threat to any plants of the Solanaceae family.
Potatoes also do not need to be planted close to the beds with tomatoes, because this culture contributes to the very rapid spread of phytophthora.
The following factors can awaken late blight spores sleeping in the ground:
- low temperature in the summer season;
- lack of air, poor aeration of tomato bushes;
- high humidity is an excellent breeding ground for microorganisms;
- exceeding the dose of nitrogen fertilizers;
- lack of elements such as potassium, iodine and manganese in the soil;
- shade or partial shade on the site, the predominance of cloudy weather;
- excessive watering;
- overgrowth of weed crops between tomato bushes;
- moisturizing tomato stems and leaves.
In order for the fight against late blight to have a result, it is first of all necessary to eliminate all factors contributing to the development of a fungal disease.
Late blight in beds and greenhouses
It is believed that the peak of late blight occurs at the end of summer - August.This month, the nights become cool, the temperature drops to 10-15 degrees, in most regions of the country the season of prolonged rains begins, and cloudy days are becoming more and more.
All this is the best fit for fungi - spores begin to multiply rapidly, capturing an ever larger territory.
Farmers consider the early varieties of tomatoes to be a salvation from late blight. It cannot be said that the tomatoes of these varieties are resistant to late blight, just the fruits on such plants have time to ripen before the epidemic begins, the peak of late blight "skips".
However, the climate of not all regions of Russia is suitable for growing early ripe tomatoes in the beds - in most of the country, summers are short and cool. Therefore, early varieties are often planted in greenhouses.
It would seem that this is the salvation from the terrible disease of tomatoes. But, unfortunately, everything is not so - in closed greenhouses, the risk of developing the disease is even higher, this is facilitated by the microclimate of the greenhouse. A particular danger is concealed by:
- poorly ventilated greenhouses;
- too thick plantings, not pinned tomatoes;
- high humidity;
- too high a temperature combined with frequent watering;
- land contaminated by previous plantings in greenhouses;
- watering is not a root type - you can only moisten the ground under the bushes, the plants themselves must remain dry.
The fact is that spores of the fungus are perfectly preserved in wood, waking up and affecting plants every season. Wood processing is ineffective; only super-early hybrid tomatoes are planted in these greenhouses, the resistance of which is the highest.
therefore selection of varieties of late blight-resistant tomatoes for a greenhouse is an even more difficult task than finding tomatoes for open ground.
What varieties of greenhouse tomatoes are resistant to late blight
No matter how hard breeders and botanists try, varieties of tomatoes that are absolutely resistant to late blight have not yet been bred. Every year, more and more late blight-resistant varieties appear, but so far there is no such tomato that will not get sick with a fungus with a 100% guarantee.
But there is a group of tomato varieties that theoretically can get sick with late blight, but for this several factors must coincide at once (for example, high humidity and low temperature or planting plants in a wooden greenhouse infected with spores).
Determinant tomatoes have the following features:
- grow to the third or fourth ovary and stop development;
- their fruiting is stretched;
- fruits are not the same size;
- the bushes do not have or have a small number of side shoots, so the plantings are not thickened and are well ventilated;
- give good yields;
- often characterized by early ripening.
Unlike undersized varieties, indeterminate tomatoThey grow up to 1.5-2 meters, have many stepchildren, differ in later ripening periods and the simultaneous return of fruits. Such plants are best grown in greenhouses, but it is imperative to monitor the humidity inside and often ventilate the greenhouse. It is tall tomatoes that are more suitable for growing for commercial purposes - the fruits are of the same size, perfect shape and ripen at the same time.
"Resonance"
The cultivar is one of the few indeterminate tomatoes that can withstand late blight. A crop with an early ripening period bears fruit as early as three months after planting.
The bushes are not very tall - up to 1.5 meters. Tomatoes are large, round, red in color, the average weight is about 0.3 kg.
The culture tolerates extreme heat and lack of watering. Tomatoes can be transported, stored for a long time, used for any purpose.
"Dubok"
Determinate tomato, compact bushes - up to 0.6 meters high.Early culture - the fruits can be plucked 2.5 months after planting the seeds. Tomatoes are small in size, painted red, have the shape of a ball, and their weight is about 100 grams.
This variety is considered one of the most resistant to late blight, tomatoes ripen together, the crop yield is high.
"Gnome"
The bushes are small, grow to a maximum of 45 cm. The culture is early, tomatoes ripen after 95 days. The tomatoes are small, about 50-60 grams each, round and red.
There are few lateral processes on the bushes, so you do not need to pinch them. The variety gives good yields - about three kilograms of tomatoes can be harvested from each plant.
"Orange miracle"
The culture is tall, with an average growing season, it is necessary to harvest in 85 days. Tomatoes are painted in a rich orange color, have the shape of a ball, but a little flattened. The color of tomatoes is due to the high content of beta-carotene, so tomatoes are very healthy.
Tomatoes are large, weigh about 0.4 kg. Plants resist late blight well and can be grown in hot and arid regions.
"Grandee"
The bushes are of a determinant type, their height is maximum 0.7 meters. Tomatoes ripen in medium terms, endure difficult climatic conditions.
Tomatoes are round and large, the weight can be 0.5 kg. The pulp of the fruit is sweet, sugary, very tasty.
Bushes of this variety must be pinched, removing the lateral processes.
"Lark"
The variety is of a hybrid type, characterized by ultra-early ripening. The culture is resistant not only to late blight, but also to several other diseases that are dangerous for tomatoes.
The bushes are of a determinant type, however, their height is quite large - about 0.9 meters. The Lark produces good yields. The tomatoes are medium in size, weighing about 100 grams. The fruits are considered tasty, suitable for processing and preservation.
"Little Prince"
A low-growing plant with compact bushes. The yield of tomatoes is not very high, but the culture staunchly resists late blight. The main protection of these tomatoes from a dangerous fungus is a short growing season, tomatoes ripen very quickly.
Tomatoes weigh a little - about 40 grams, have a good taste, are great for pickling.
"De Barao"
Indeterminate tomatoes, which need to be grown in greenhouses. Plants stretch up to two meters, they need to be strengthened with supports. The culture has a strong immunity against late blight, even despite the late ripening period, this variety rarely suffers from fungal ailments.
Tomatoes ripen four months after sowing, are plum-shaped, weigh about 60 grams. A distinctive feature is a very rich cherry hue of the fruit, sometimes tomatoes are almost black.
Up to five kilograms of tomatoes are harvested from the bush, they can be stored for a long time, used for any purpose.
"Cardinal"
A greenhouse crop that grows up to 180 cm has an average growing season. The fruits are distinguished by an interesting heart shape, a large weight - up to 0.5-0.6 kg. The variety gives a good yield, has a high taste.
Late blight will not touch these tomatoes if the greenhouse is well ventilated and excessive humidity inside it is not allowed.
"Carlson"
These tomatoes ripen 80 days after planting. The bushes are quite high - up to two meters. The shape of the tomatoes is elongated, at the end of the fruit there is a small "nose", they weigh about 250 grams.
From each such tall bush, you can collect up to ten kilograms of tomato. Such tomatoes are stored for a long time, can be transported, they are very tasty.
How to deal with late blight
As mentioned above, phytophthora is easier to prevent than to defeat. This is a very persistent disease for which it is difficult to find a "treatment". To identify the disease in the early stages, the gardener should check the bushes and leaves daily, pay attention to light or dark spots on the leaves - this is how late blight begins to develop.
It is better to remove an already ailing tomato bush from the garden so that neighboring plants do not become infected.If most of the tomatoes are affected, you can try to cure those plants. For these purposes, many means are used, in some cases some "medicines" help, in others - they turn out to be absolutely useless, then you need to try something else.
Modern gardeners most often use such means. from late blight:
- "Baktofit", diluted in water, according to the instructions, and applied under the bush together with watering;
- fungicidal drugs used to irrigate bushes;
- Bordeaux mixture;
- copper oxychloride;
- folk remedies such as iodine, milk, mustard, manganese and even brilliant green.
You can help plants resist late blight at all stages of development. For this:
- Process tomato seeds before planting with a manganese solution.
- Spill the ground with boiling water or potassium permanganate, fungicidal preparations.
- Water the bushes only at the root, carefully making sure that no drops of water fall on the leaves.
- In rainy and cool weather, especially carefully monitor the plants, carry out regular processing of the bushes.
- Mulch the soil between the tomato bushes.
- Stop any processing 10-20 days before fruit ripening.
- Planting mustard and basil between rows of tomatoes - these plants kill phytophthora spores.
- Remove tomato leaves that touch the ground.
- Tie up the stems of tomatoes, lifting the plants so that they are better ventilated.
Phyto-resistant tomato varieties are not a 100% guarantee of a healthy harvest. Of course, such tomatoes better resist the causative agent of the disease, their natural resistance has been multiplied by breeders. But only an integrated approach to the problem of late blight can be considered truly effective:
- purchase of resistant varieties;
- seed treatment;
- disinfection of soil;
- compliance with the rules for growing tomatoes;
- timely and regular processing of plants.
This is the only way to be sure of your tomato harvest!
