Growing tomatoes, gardeners are faced with many different diseases of tomatoes. One of the most common is vertex rot, which affects fruits in both open and protected ground. In some years, crop losses from vertebral rot are 20-30%.
The characteristic signs of the disease are the formation at the top of the fetus of brown, flat, concentric, several sunken spots. The affected tissue under the epidermis softens and rots. Such fruits often fall and produce low-quality seeds.
In places of apical rot manifestation, various saprophytic fungi can be populated, most often of the genus Alternaria. Then, due to the sporulation of the fungus and the formation of a mass of black conidia, the affected tissue becomes black. One of the main reasons for the appearance of vertex rot, many researchers consider high temperatures and lack of moisture.
In dry and hot weather, evaporation of moisture from leaves intensifies, the root system does not have time to replenish the aboveground mass of plants with water, and this causes the outflow of part of the moisture from the fruits to the leaves. Under such conditions, a part of the fetal cells dies. The increased manifestation of apical rot occurs on soils with insufficient or excessive amounts of calcium. Significant top rot damage is also observed on saline soils.
Since the top rot of fruits is associated with the alternation of dry and moist soil, as well as with insufficient absorption of calcium by plants, in order to prevent the disease, it is necessary to regulate the water and nutritional regime during plant vegetation. Watering in a timely manner, avoiding overdrying and overheating of the soil, as well as apply the foliar top dressing with special preparations.
In the case of calcium deficiency, the treatment of plants with preparations is very effective, which, in addition to the main nutrients (nitrogen, phosphorus, potassium), also contains calcium and boron trace elements available to the plant. Calcium intake inhibits boron deficiency.
With a lack of boron, the weak bloom is observed, the growth point dies, the root growth stops. Boron is considered a calcium synergist (synergists are substances that act in such a way that the activity of their mixture exceeds the sum of the activity of the components). Therefore, in order to increase the effectiveness of calcium chelate, boron is added to the composition of some drugs. For example, Brexit Mix contains 15% calcium and 0.5% boron.
This preparation does not contain nitrogen, and calcium is in it in the form of a complex based on a natural agent – lignosulfonate, which allows achieving high efficiency with foliar top dressing. Processing is carried out with an interval of 10-15 days at the rate of 10 g of the drug per 10 l of water. If there is a lack of calcium in the soil, it must be liming before plowing.
Antistressants and Stimulants
In addition, various stressful situations, as well as natural factors (frost, drought, hail, etc.), and human exposure (chemical treatments, mechanical damage to the roots) can lead to significant crop losses and lower product quality. Under the influence of stressful conditions, the plant loses its ability to absorb nutrients and stops in growth and development. Therefore, it is very important in such cases to use antistressants and growth stimulants, which help to overcome adverse development conditions. There are a lot of such drugs today. One of them is a tomato rescuer, which consists of plant amino acids, polysaccharides, prohormonal compounds. Thanks to this composition, the drug stimulates metabolic processes, the absorption of nutrients. Amino acids perform transport functions to deliver nutrients and water to plant cells, stimulate chlorophyll synthesis, enhance the ability of the root system to absorb water, and increase resistance to low and high temperatures. The drug is effective for foliar top dressing. It is used at a concentration of 0.25% for the first time 10-15 days after transplanting, the following treatments are done every 2 weeks as needed. Good results are obtained with the combined use of Brexit and a tomato rescuer. Very effective antistressants and plant growth stimulants based on humic acids. For example, quantum contains about 85% of biologically active substances – humic and fulvic acids. Its action is enhanced at critical temperatures. With poor plant development and drought, it has a beneficial effect on the plant during foliar treatments alone or in tank mixtures with other drugs. It is used in a concentration of 0.02-0.05%.
For faster ripening of the fruits, enhancing their color, the accumulation of high content of sugars and vitamin C, before starting natural staining, the drug SVIT, 02-04%, is used together with the megafol preparation. Sheet processing with SWEET does not cause aging of the plant and dying off of the leaf apparatus, but in stressful situations (drought, high humidity, low temperature) it allows to maintain high-quality indicators of fruits.