Tomato curl

Like many other vegetable crops, tomatoes are often affected by a variety of diseases caused by fungal spores, pathogenic bacteria and viruses. Moreover, both greenhouse tomatoes and those cultivated in a greenhouse can get sick. The reason for the development of infections can be both unfavorable environmental conditions and violations of agrotechnical requirements for the cultivation of a particular plant culture. This article will focus on such a disease as tomato curl.

Tomato curl: the etiology of the virus

Tomato leaf curl: photo of the virus

Of all the diseases that affect tomato bushes, viral infections are considered the most dangerous and almost impossible to treat. Often, the only way out for the owner of problematic tomato beds is to destroy the infected bushes. They have to not only be dug up and removed from the site, but also burned.

Thus, it is possible to prevent the spread of the disease to the extent of an epidemic, when there is a risk of losing the entire crop of tomatoes this season. The curliness of the leaves of tomatoes of a chlorotic nature is just such a dangerous and practically incurable disease.

Chlorosis is an indispensable companion of this disease. In the leaves, the process of chlorophyll formation is disrupted, which leads to their deformation, growth retardation, and color change. If in the normal state the tomato foliage is painted in a dark green saturated color, then the chlorotic foliage has a pale color of light green, or even a yellow hue.

As for the shape of the leaves, the top of the bush really begins to curl - hence the name of the disease. In general, all processes in the plant are inhibited, it looks weak and sick.

The source of tomato leaf curl disease is most often a virus - "Tomato leaf curl virus". The history of its study began in the early 90s, when Californian vegetable growers first encountered it.

Tomato curl virus spread rapidly and in 1994 it was found in Central Asia, on the territory of Turkmen vegetable farms. After another 3 years, the virus reached the Mediterranean and began to infect greenhouse tomato plantings in Italy.

Tomato curl is not one of the most common ailments of this crop, but it poses a serious threat to the crop. Despite the fact that no cases of mechanical transmission of the virus have yet been recorded, it has enough paths of spread.

Infected seed and soil left over from infected tomato plantings retain traces of the virus and are the source of damage. The tomato curl virus is transmitted with the help of insect pests - whiteflies, which themselves can damage the crop, but become even more dangerous as vectors of diseases.

Tomato leaf curl: symptoms and characteristic manifestations of infection

Yellow curl of tomato leaves: photo of the virus

The main symptoms of chlorotic curl infestation in tomato bushes are as follows:

• Due to the violation of the process of chlorophyll formation, tomato leaves gradually change color from dark green to yellow.
• Often, plastic leaves turn yellow not entirely, but only along the edges.
• The contours of the leaves are deformed.They themselves become smaller, begin to curl into a tube, and the tops of the bushes curl.
• The plant affected by the virus begins to lag behind in development, weakens, or even stops growing altogether, which significantly differs from the neighboring bushes.
• The green mass of tomato bushes is thinning, the stems are bare in places, some shoots remain completely without leaves.
• Color production is uneven. Some inflorescences can not hold on to diseased shoots and crumble.
• If the ovaries are formed, they quickly harden, and remain small. Further fruit ripening may not occur.
• The foliage of tomato bushes not only changes color, but also shrivels.

On average, it takes about a month from the moment a plant is damaged by a virus until the first characteristic signs of infection appear. Infection with curly tomato leaves occurs throughout the growing season.

Despite the relative rarity of the disease, in the context of its epidemic spread, significant damage to the crop can be caused. The loss is at best 17% of its total volume, in the worst case, a complete loss of fetuses is likely.

Chlorotic curliness of tomatoes affects not only tomato plantings. Other nightshade crops, as well as varieties of lettuce, are susceptible to this disease.

At the moment, not a single hybrid tomato variety has been developed that would have immunity to the leaf curl virus. Therefore, the disease threatens any vegetable farm.

Tomato curl: treatment

Tomato leaf curl: photo of the virus

As a rule, the yellow curliness of tomatoes reveals itself when the infection has already largely covered the plant. In this case, the treatment will not give results or will require unjustified efforts and costs. Therefore, it will be more expedient to remove the diseased plant from the garden.

Then it must be destroyed. This will reduce the risk of spreading the infection to neighboring tomato bushes. The algorithm of actions when working with infected bushes involves the following steps:

• Before starting work, you need to take care of personal protective equipment - you need rubber gloves.
• A diseased tomato bush should be removed along with the root system, without leaving shoots in the soil. It is necessary to remove foliage and shoots that have fallen from it from the garden. All this must be burned, since the virus can persist in plant debris.
• Using parts of an infected plant for composting is absolutely contraindicated.
• The place for burning infected plants should be at a considerable distance from the beds.
• The remaining tomato bushes should be treated with a solution of Bordeaux mixture (1%) or copper sulfate.
• Garden tools used during work must be thoroughly cleaned and disinfected. Ethyl alcohol is ideal for this purpose.

In cases where the plant is slightly infected, you can limit yourself to removing the infected leaves and shoots. And process the rest of the bush using the tools described above. Broken leaves and shoots should be burned.

Watering mode for tomatoes

One of the factors that significantly affect the risk of developing chlorotic curl in tomato leaves is the level of humidity in the air and soil in the area with tomatoes. Compliance with the watering regime is extremely important, especially for tomatoes that are grown in greenhouses.

Preventive treatment of plants from tomato curl virus

Tomato leaf curl: photo of the virus

As mentioned above, the quality of the seed plays an important role. Preventive treatment of seeds, as well as bushes of seedlings and even the soil is necessary to prevent them from contracting the virus.

Disinfecting seeds is easy enough. They can be placed in a potassium permanganate solution before sowing. The soil is spilled with it before planting, seedlings are sprayed.

Since the whitefly is the carrier of the virus, it is necessary to take timely measures to protect the tomato plantings from this dangerous pest. You can recognize him by his rather harmless appearance. The whitefly looks like a small white moth.

To prevent its penetration into the site, you should periodically treat the tomato beds with insecticides. There are many effective chemicals available in gardening stores.

The same gardeners who do not trust the finished product have several folk recipes to choose from. For example, infusions of garlic, tobacco crumbs, or dandelions are suitable. You can scare off a whitefly using a fumigator, or vice versa - lure it with a trap and then destroy it.

Another preventive measure that increases the immunity of plants and their resistance to diseases is spraying the bushes with copper solutions.

Soil cultivation in tomato beds

Caring for the soil is no less important than caring for the seed and the tomato bushes themselves. The necessary soil treatment measures include the following procedures:

• Such a simple measure as deep digging of soil at the site and its regular loosening helps to destroy a significant part of pathogens of viral, fungal and bacterial infections.
• Compliance with crop rotation rules will also reduce the risk of infection. Since replanting the same crops on the site increases the likelihood of transmission of the virus to tomato bushes planted in the new season. Therefore, it is necessary to alternate the placement of certain crops on the site.
• In cases where it is not possible to change crops on the site, it is recommended to replace the soil and first carry out the procedure for its disinfection.
• Too high a planting density is not desirable as it increases the risk of a virus outbreak. Keeping a sufficient distance between the tomato bushes will give them some degree of protection from infestation. The optimum spacing between bushes is 0.5 m.

At the moment, preventive procedures are the most effective way to combat the chlorotic curl virus of tomato leaves, since it is practically not amenable to treatment.

Tomato curl virus of non-infectious origin

Tomato leaf curl: photo of the virus

Sometimes the leaves of tomatoes curl for other reasons, not related to infection. However, this does not reduce the risk of crop loss, since as the area decreases, the leaf plates cease to receive enough sunlight and do not produce the substances necessary for fruit ripening.

The following factors can cause curly leaves of tomatoes:

• Lack of moisture in the greenhouse, combined with high air temperatures, leads to leaf deformation. They curl into a tube along their entire length. To prevent this from happening, it is necessary to spray the tomato bushes and regularly ventilate the greenhouse. Another solution to the problem is choosing drought-resistant tomato varieties.
• Sometimes the curliness of the top of the tomato bush is accompanied by a build-up of green mass in the rest of the plant. The reason for this is the excess of nitrogen in the soil and the abuse of fresh manure fertilizers at the time of planting the bushes. It is recommended to feed young tomato bushes with thoroughly rotted compost. At the end of summer, the introduction of dressings based on potassium and phosphorus is shown.
• Rolling the leaves inside out is a sign of a deficiency of such an important and beloved substance as phosphorus. Even at the seedling stage, during a pick, it is necessary to feed young plants with superphosphate. During the season, it is recommended to fertilize the tomato beds several times with phosphorus mixtures.
• The lack of another important macronutrient leads to curling of tomato leaves towards the center of the plate, as well as curliness of new leaves and uneven ripening of fruits. The sides of the tomatoes are covered with yellowish spots. This is due to potassium deficiency, so it is very important to timely replenish its deficiency in the soil.
• Copper deficiency has similar symptoms. As a rule, this applies to those tomato bushes that are planted in peat-rich soil. The flowering of the bushes may not start, or be weak and uneven. The situation can be corrected by fertilizing the beds with tomatoes with a solution of copper sulfate, or other mixtures containing copper.
• Yellow curl on tomato leaves is also often caused by excess moisture in the soil. Especially when combined with a lot of nitrogen. As a rule, in this case, the lower leaves are curled first.
• Overuse of mullein-based feeding can lead to curly leaves. Therefore, it should be remembered that this fertilizer is applied only at the very beginning of the tomato flowering phase. In the process of plant development, it is much more beneficial to feed it with fertilizers based on phosphorus and potassium.
• A sign of a lack of phosphorus can be the appearance of purple veins on the leaves. The regime of watering tomatoes involves carrying out this procedure no more than once every 2 weeks, while a lot of water is required: in a greenhouse, about 10 liters of water are consumed per 1 bush, in open beds - up to 6 liters.
• Another likely reason for curling leaves on tomato bushes is a violation of the rules for carrying out pinching. Knowing that during the rapid growth and development of tomato bushes, regular removal of newly appeared shoots is required, many gardeners cut off the lower leaves with them. As a result, the plants receive stress, the process of their nutrition is disrupted, which immediately affects the remaining foliage and even the inflorescences that begin to fall off. Delayed removal of stepchildren also disrupts the metabolism of the plant and leads to deformation of the leaves. Therefore, it is recommended to carry out pinching when the length of the side shoots reaches 1.5-3 cm. When pinching, as well as when pinching the tops of tomato bushes, it is important to observe the measure and not remove more than 2-3 leaves from one bush. During this period, you should not water the plants, and for better wound healing, you can spray them with the biostimulator "Zircon".