How to treat beetroot cercosporosis and prevent the occurrence of this disease in the future

Paracelsus used beets in the 16th century to treat anemia. But despite its healing properties, the plant itself is subject to many diseases... One of them is cercosporosis. Read about the symptoms of the disease, measures to combat it in our article.

What is beet cercospora

Cercosporosis is a fungal infection. The causative agent is Cercospora beet (Cercospora beticola). Hibernates in the form of mycelium in dead leaves and petioles, remains in seed glomeruli. The pathogen remains viable only in the upper soil layers (no deeper than 10 cm) or on plant debris located on the soil surface. In spring, it forms spores, which are the primary source of infection.

Infection occurs through the penetration of spores into plant tissues through stomata and mechanical damage.

The incubation period in summer is 7-10 days, in cool spring or autumn - up to 30 days. For sporulation of the fungus, a temperature of 15-35 ° C is favorable. When it rises to 40 ° C, the development of the pathogen stops. The fungus spreads quickly at a humidity of 98-100%, a level below 88% is detrimental to the pest. Sunlight inhibits the formation of spores.

Cercosporosis leads to pathological changes in the work of the leaf apparatus. In infected plants, the level of transpiration (physiological evaporation of water) increases, which leads to an imbalance of nutrients in the tissues. The assimilation of carbon dioxide decreases 10 times, nitrogen metabolism worsens.

Maintaining the vegetation of the leaves is due to the forces of the root crop. By the fall, new leaves may grow and the rows will look healthy. However, full-fledged root crops will not be formed, the yield will decrease by 30-70%. When storing such beet rots.

The disease is most common in western Ukraine, Kazakhstan and the Krasnodar Territory. In the Central Black Earth Region and Siberia, it is found less often and on a smaller scale.

Reference.Cercosporosis affects not only beets, but also potatoes, soybeans, peas and other crops.

Reasons for the appearance

The appearance of fungus on plants is caused by a heat lasting more than 40 days with temperatures above 25 ° C during the day and above 15 ° C at night. A mandatory factor is humidity over 70% for a long period. With a rainfall of 180-200 mm during the summer, the likelihood of infection increases many times.

Symptoms

The first signs of the disease can be found in June-July.

Small rounded spots of light brown color appear on the leaves, surrounded by a pronounced red-brown border. At first, the diameter of the lesions does not exceed 0.5-0.8 mm, as the infection develops, they increase to 2-4 mm.

First of all, the disease is noticeable on the outermost leaves in the outlet. Slightly depressed elongated light brown spots are visible on the petioles and stems.

With increased humidity, a velvety gray coating appears on the lesions.

If you do not fight with cercospora, the leaf plates twist, wither and die off. Tops falls on the ground, the aisles open.

To maintain life, the plant spends nutrients intended for the growth of root crops on the vegetation of young leaves.

Control methods

Infection control methods are divided into two groups: agrotechnical and chemical. There are no effective alternative methods of treating beet cercospora.

Agrotechnical measures

Before planting a vegetable, measures are taken to destroy the overwintered pathogens of infections. The site is examined, all the remnants of rotten plants are removed.Presowing soil preparation consists of deep digging, if this has not been done since autumn, and thorough loosening to a fine crumbly state.

During the growing season, it is important to maintain the topsoil in a loose state, which improves air access to root crops and retains moisture.

It is necessary to weed the beds in a timely manner. Weeds oppress beets, serve as a source of diseases and various pests.

Feeding will relieve planting of starvation diseases. At the first signs of cercosporosis, potassium-phosphorus fertilizers should be applied.

Reference.Agrotechnical measures are aimed at maintaining overall health and strengthening plant immunity.

Chemicals

In June and the first half of July, at the first signs of the appearance of pathogens of cercosporosis, beets are treated with fungicidal preparations.

Effective against them:

1. "Fundazol" ("Benomil") belongs to the class of benzimidazoles, has a broad spectrum of action against most fungal infections. It is used for plant treatment and seed dressing. The action is based on a violation of the reproductive function of the fungus. The drug has a systemic effect, as it is partially absorbed by plant tissues; most of it remains on the surface of the leaves and has a contact effect on pathogenic organisms. Available as a 50% wettable powder. To treat the beds, 10 g of the drug are diluted in 10 liters of water. Consumption of working solution: 1.5 liters per 10 m². The emergence of pest resistance to pesticides is possible, so it needs to be alternated with others. The substance is not toxic to bees, but dangerous to humans, animals and fish.
2. "Kuprozan" ("Hometsin") is a contact fungicide. It is a mixture of 4 parts of copper oxychloride and 1 part of zineb. Produced in powder form. To prepare a working suspension, take 40 g of the drug per 10 liters of water. Consumption - about 1 liter per 10 m². Low toxic to bees, has a moderate toxic effect on humans and animals.
3. Copper oxychloride (HOM) - an inexpensive drug of protective contact action. It is recommended to be used as a preventive measure before symptoms of the disease appear. The frequency of treatments is 3 times per season with an interval of about 2 weeks. A plant treatment liquid is prepared from 40 g of the substance per 10 liters of water. Spraying is carried out at the rate of 1 liter per 10 m². Possesses moderate danger to humans.

Spraying against cercosporosis is carried out only in wet weather, after heavy rain or dew. The air temperature in this case should be 20-25 ° C. Cold weather treatments (about 15 ° C) are ineffective. In dry and hot periods, fungicides are not recommended.

Treatments must be carried out no later than 30 days before harvest.

Important! It is imperative to work with chemicals in closed clothing, a hat, rubber gloves, a respirator and goggles. After work, the face and hands are thoroughly washed, the clothes are washed.

Prevention

There are several effective methods to protect beet plantings from the causative agent of cercospora.

First, you need to follow the rules crop rotation. To avoid the accumulation of pathogenic microorganisms helps sowing beets in their original place no earlier than two years later.

Secondly, immediately after harvesting the root crops, the remains of the tops are completely removed from the beds. They can be used as animal feed.

Thirdly, the areas for beets are dug deeply in the fall. Fungal spores at a depth of more than 10 cm will lose their viability during the winter.

Finally, varieties that are resistant to disease should be selected. For example, Incomparable A-463, Mulatto, Bravo, hybrid Rocket F1.

Conclusion

Cercosporosis of beets is a serious disease that reduces the yield by 30-70%, the quality and keeping quality of root crops. The causative agent of the infection, the cercospora beet fungus, develops in a humid and warm environment.The first signs appear in June-July as small rounded spots with a reddish-brown border. At an advanced stage of the disease, the leaves curl, wither and die off. Control measures consist in proper agricultural technology (timely weeding, loosening, feeding) and treatment with fungicides.

An excellent prevention of cercosporosis is crop rotation, deep autumn digging of plots for beets, cleaning of all plant residues from the beds. An attentive attitude to plants, regular examinations for the presence of pests and infections will help to notice the problem in a timely manner and eliminate it without significant efforts.