In recent years, tomatoes in greenhouses often have viral diseases, causing tomato production to be reduced or even lost. Because the disease is not controlled by specific drugs, it is easy to infect and causes huge losses. Therefore, the farmers often talk about "virus and discoloration." One of the most obvious physiological manifestations of viral diseases is leaf rolling. Some farmers often do not clearly understand the true cause of leaf curling in tomatoes. As a result, some leaf diseases that are not viral diseases are often mistakenly referred to as viral diseases, causing unnecessary deforestation. In greenhouses, there are leaf curls on tomato plants. In general, there are many situations such as leaf curling, leaf curling due to physiological diseases, and rolling leaves caused by diseases and insect pests. The production should be treated differently.
1. Virus disease damage. Virus disease can easily lead to curling of tomato plants and leaf curling. In severe cases, only leaf veins and no mesophyll are involved. Viral diseases are transmitted through infected aphids, whiteflies, or sap, and high-temperature and dry conditions are favorable for this. After tomato plants were infected with the yellow mosaic virus, the plants were dwarfed, the young leaves of the terminal buds were slender, spirally rolled down, and the middle and lower leaves rolled upward. After infection with the yellow leaf curl virus, the young leaves of the top buds are pale, yellow, and the leaves curl upward. Once a tomato is infected with a virus, drug control is very difficult. Therefore, prevention should be the main method and comprehensive management should be implemented. Control measures: selection of disease-resistant varieties; implementation of crop rotation to reduce the initial infestation source; soaking seeds with 10% trisodium phosphate solution for 30 minutes to disinfect the seeds to eliminate germs on the surface of the seeds; spraying 1000 times potassium permanganate in the early stage; Use 10% net 1500 to 2000 times the liquid to kill the aphids and whiteflies.
2. Physiological roll. The condition of the soil can be seen from the curling condition of the tomato. If the soil water is too saturated, the tomato leaves will be rolled up. If the soil is dry, the tomato leaves will be rolled down. At this time, the watering of the tomatoes will be timely. Before and after the harvest of the tomato, the first ear was slightly rolled, or the whole leaf was curled into a tube and became brittle. This was mainly due to high temperature and drought, and the stomata of the tomato was closed and the leaf curled. Preventive measures: timely watering and fertilizer application after fruiting, covering the shade net, cover during sunny day and night, exposing at night, and not covering cloudy days.
3. Tea is damaged. The tea planted pods gathered larvae and young larvae to suck the sap in the young part, resulting in narrowing, thickening, stiffness, shrinkage or distortion of the leaves. Symptoms are narrowing of the leaves, stiffness, erection, shrinkage, or distortion, and finally, baldness. The control agent can be sprayed with 1.8% afordin 3000 times spray, 1.0% Emamectin EC (Haizheng Sanling or cloud addition, green card, etc.), or 2.5% Uranus EC, or 10% diluting SC, etc. The focus is on the young part and the top of the leaf, once in 7-10 days, and even spraying three times, the effect is obvious.
4. The lack of disease. The lack of phosphorus showed purple backs, brown spots on the leaves, the lower leaves rolled up, the leaves turned yellow, and the tip dark brown withered. Can be applied to soil by applying phosphate fertilizer, or foliar application of 0.3% potassium dihydrogen phosphate solution. Magnesium deficiency manifested in the first inflorescence fruit expansion period. The lower part of the plant's gray leaves lost chlorosis and yellowing appeared between veins. Then it expanded upwards to form yellow variegated leaves. When severe, the leaves were stiff or rolled up on the edges, and necrotic spots appeared between veins. Brown block band. Magnesium deficiency can be solved by applying 100% solution of full-element fertilizer or foliar spray magnesium sulfate.
5. Hormonal injury. In the use of plant hormones to prevent flowering and fruit drop, if 2,4-D is accidentally picked up on young leaves or growing points, there will be bending of the leaves or growing points, the new leaves will not be able to spread properly, and the green leaves will be distorted. Prevention and control measures: Select the appropriate concentration when using, generally use the concentration of 15 ~ 20 mg / kg, the concentration is lower when the temperature is high. When using, be careful not to spray the liquid onto the leaves or growing points. Do not spray it. After the occurrence of phytotoxicity, some growth-promoting nutrient liquids can be applied, such as natural brassinolide spray and love overdose.
Sweeteners are food additives that sweeten soft drinks. Sweeteners can be divided into nutritional sweeteners and non-nutritional sweeteners according to their nutritional value. According to its sweetness, it can be divided into low sweetness sweetness and high sweetness sweetness I flavor; According to its source can be divided into natural sweeteners and synthetic sweeteners. Natural sweeteners include stevia, grosvenin, licorice, disodium glycyrrhizinate, tripotassium glycyrrhizinate and trisodium.
Mogroside V,Compound sweetener,Stevia Leaf Extract,Monk Fruit Extract,Fructus Monordicae Extract
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