What to do if the autumn and winter tomato "soy sauce fruit" is ugly and hard to sell

If you want to sell vegetables at a good price, "value" is very important. In autumn and winter, the "soy sauce fruit" that is easy to appear in tomato planting is a disease that greatly affects the "look". So, how did "soy sauce fruit" happen? How to prevent this disease in production?

1. Symptoms Tomato "soy sauce fruit" means that there are brown or soy sauce-colored patches on the surface of the fruit. The lesions vary in size and only appear on the peel. After the peel is peeled, the inner color is normal. In the early stage, the color of the surface of the fruit is light and difficult to be found. Later, it becomes dark brown to brown with obvious edges and slight depressions. The disease usually starts from the shoulder of the fruit, and the fruit texture is hard and not soft. It usually occurs during the fruit swelling period, but it is not discovered until the fruit color change period.

Second, the law of the incidence of tomato "soy sauce fruit" is generally more serious on autumn and winter tomatoes, and the shed partial application of nitrogen fertilizer, low temperature, high humidity, poor ventilation, excessive cultivation density, the disease is more serious, the same shed indoor greenhouse In general, large-fruited varieties are more susceptible to disease than cherry tomatoes. Varieties with thin skins are more susceptible than those with thicker skins. Varieties with fast fruit expansion during fruit expansion are more susceptible than those with slower expansion.

3. Causes of disease 1. Calcium deficiency leads to a decrease in the hardness of the cell wall of the tomato peel, resulting in a thinner peel, which is susceptible to infection. There are two main reasons for the lack of calcium in tomatoes:

Fertilization is unreasonable. In tomato cultivation, vegetable farmers apply a large amount of nitrogen fertilizer in pursuit of yield, and excessively apply high potassium fertilizer during the fruit expansion period, which reduces the calcium absorption of tomatoes and causes calcium deficiency in plants.

Determined by the transport properties of calcium in plants. The transportation of calcium in plants mainly relies on transpiration, and it is difficult to redistribute in plants. Therefore, the calcium content in fruits is much lower than that in leaves, resulting in calcium deficiency in fruits. The lack of calcium in the fruit reduces the hardness of the skin cell wall and increases the chance of disease.

2. Improper temperature management Another reason for the occurrence of tomato "soy sauce fruit" may be due to improper management that causes poor color conversion of tomatoes, resulting in abnormal changes in the color of tomatoes during the color conversion process. Under normal circumstances, chlorophyll is gradually decomposed during the color conversion period of tomato, and a large amount of lycopene is formed, which makes the fruit present a bright color.

For example, when the temperature of tomato color conversion period is too high or too low, it is not conducive to the formation of lycopene. The most suitable temperature for lycopene formation is 24°C. Above 28°C, the formation of lycopene stops; below 15°C, the formation of lycopene decreases significantly.

3. Excessive humidity. In actual production, tomatoes are severely affected in autumn and winter. At this time, the sheds with low temperature, high humidity and poor ventilation are severely affected. The incidence rate of the front face in the same shed is higher, but in different sheds, the incidence of high humidity is higher than that of low humidity sheds.

4. Viral diseases are caused by the occurrence of "soy sauce fruit" due to the infection of the fruit. In this case, the leaves are often uneven, deformed and other viral disease symptoms, and the disease usually occurs in a certain area, and the surrounding area is light, that is, there is one disease. center.

Fourth, prevention and control methods Tomato "soy sauce fruit" prevention is more important than cure. Because once soy sauce spots appear on the fruit surface, it is difficult to change. Therefore, vegetable farmers must do a good job in prevention.

1. Balance fertilization to avoid partial application of nitrogen fertilizer and excessive application of potassium fertilizer, and spray calcium fertilizer and boron fertilizer on the leaves during the fruit expansion period.

2. Appropriately reduce the humidity in the shed. Watering is the primary factor affecting the air humidity in the shed. Drip irrigation can be used if conditions permit, or small water can be used to avoid flooding. The humidity in the shed can be reduced by means of split ventilation or covering the crushed straw in the operation line.

After watering, increase the temperature and remove moisture in time. On the basis of controlling the temperature of the shed, the better the moisture removal measures, the less dripping of the shed film, the more helpful it is to prevent the disease; you can choose a non-drip film; if you find the shed film When the internal condensation is serious, you can also use the silicone water spray to improve the ductility of the water droplets on the shed film and avoid condensation.

3. Temperature control The color change period of tomato should be controlled at about 24°C during the day, with the highest temperature not exceeding 28°C and no lower than 12°C at night. A suitable shed temperature is conducive to promoting the red ripeness of the fruit, which not only ripens quickly but also has good coloring, and the fruit has good commercial properties. Therefore, in management, it is necessary to prevent the temperature of the shed from rising, falling, or dropping suddenly, and the top wind should be used to release the wind, and the cold air should not be directly blown into the shed from the bottom.

4. Reasonably close planting to keep the field ventilated and light, and timely remove the old leaves and yellow leaves under the plant. Don't pick too much leaves. Leave a few leaves on the top of each ear of fruit to prevent the surface of the fruit from being burned by strong light.

5. Prevention in advance For the "soy sauce fruit" caused by viral diseases, it is necessary to prevent and control viral diseases in advance. First, prevent glare, planthoppers, and drought, hang yellow boards, and use spirotetramat and cyantraniliprole , Thiamethoxam, Flupyridone and other agents are sprayed alternately to control whitefly, Bemisia tabaci and other planthopper pests; and Ningnanmycin, lentinan, morpholinoguanidine hydrochloride and other agents are sprayed for prevention and control. Control the virus.

6. In the production of medicament prevention and control, 23.4% dipropynyl sulfonate 1500 times liquid, 70% propisen zinc wettable powder 600 times liquid, 75% mancozeb wettable powder 600 times liquid or 440 g/L refined 800 times liquid of chlorothalonil suspension agent and so on for prevention. 3 to 5 days after spraying, timely supplement of foliar calcium fertilizer and immune inducer to supplement nutrition can play a good control effect.

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