Surely many of those who have their own garden, at least once had to see the consequences of the tobacco mosaic virus. In this article, you will learn how to prevent the appearance of this disease in tomatoes.
Brief historical background
This disease was first recorded at the end of the 19th century in the process of growing tobacco. Bright marks appeared on the infected bush. Over time, he began to lose shape and eventually died. After that, the disease gradually spread to neighboring plants and after a short time the whole plantations became unsuitable for further cultivation.
The only available control method at that time was the complete destruction of infected seedlings. Similar measures made it possible to preserve the remaining plants. Many years after the discovery of this disease, Dr. Ivanovsky managed to identify its cause. She turned out to be a tobacco mosaic virus.
Development Mechanism and Biology
The causative agent of this disease is characterized by resistance to external factors. It has been established that the virus is able to persist even at elevated temperatures.
Tobacco mosaic completely infects plant tissue at the cellular level. The cause of its occurrence is the partial decomposition of chlorophyll and damage to chloroplasts. As plastids break down, carbohydrates decrease. As a result, the mechanism of dying off of individual tissue sites is activated. The causative agents of the disease are Solanum virus 1, Cummis virus 2 and Nicotina virus 1.
Main symptoms
Initially, the leaves on which the tobacco mosaic appeared become mottled. The color of the spots may vary. They are whitish, bright green or light yellow. Gradually, the leaves begin to wrinkle and deform, acquiring a filiform or fern-like shape.
In addition, tobacco mosaic leads to grinding and uneven ripening of fruits. The development and growth of an infected plant is slowed down. Due to the violation of water metabolism, the leaves and stems dry out. Young shoots are the first to die. Damaged fruits become covered with brown marks and begin to rot.
How does infection happen?
Tobacco mosaic of tomatoes can be transmitted as a result of contact with infected crops or with mechanical damage that occurs during processing. Often, infection occurs during a dive of thick seedlings.
Tobacco mosaics also spread using vectors such as bedbugs, aphids, and other insects. The virus can be transmitted through seeds and fruits carried by animals and birds. The main breeding ground for infection is soil located under the roots of diseased tomatoes. This is due to the fact that plant debris can be stored in it. Especially rapidly developing mosaic in conditions of high humidity. It has been established that raindrops flowing from the leaves of infected plants can also become an infection carrier.
Tobacco mosaic: treatment and prevention
This infection can destroy about 20% of the total crop. Therefore, it must be fought. To protect your plants, you must use exclusively high-quality planting material. Seeds, boxes and other garden tools are recommended to be treated with a five percent solution of potassium permanganate. Such manipulations must be carried out for four consecutive days.
To prevent possible infection of the future crop, preventive measures should not be neglected. So, it is important to vaccinate tomatoes with an aggressive strain. When planting plants in a greenhouse, appropriate protective measures must be taken. To disinfect the seeds, it is recommended to pre-soak them in a twenty percent solution of hydrochloric acid and rinse thoroughly under a stream of clean running water. You should also steaming the soil, pouring it with boiling water for two or three hours.
At least once a week, seedlings are recommended to be treated with milk diluted with ordinary water in a ratio of 1:10. Among other things, it is important to timely replace the soil in the greenhouse, removing a ten-centimeter layer from it along with the remains of plants.
One week before planting in the soil and fourteen days after it, seedlings should be sprayed with a one percent solution of boric acid. Thanks to this, it will become more resistant to viruses. You can not neglect the measures aimed at the destruction of insects, which can become potential carriers of the mosaic pathogen. Also, in order to prevent the likely spread of tobacco mosaic of tomatoes, experts recommend processing greenhouses, collecting and burning autumn foliage and old plant roots.