How to manage greenhouse tomatoes in foggy days?

Later, the shed film was opened for ventilation, and 1 was used to reduce the humidity and increase the light.

Everyone should do everything possible to reduce the humidity in the shed. If possible in the morning, you can properly open the tuyere (about 10 minutes) to discharge moisture. In addition, even if it is cloudy, the drafting felt should be pulled out, otherwise the plants will not be able to carry out photosynthesis and will become weaker and weaker. If the conditions are good, you can also use a fill light to increase the light;

2. Strengthen cultivation management and do farm work well.

The more severe weather conditions are encountered, the more careful management is needed, such as destroying redundant leaves, reducing nutrient consumption on the one hand and reducing humidity on the other. Also, once leaves, flowers and young fruits with serious diseases are found, they must be picked up in time, wrapped and thrown away, and don't bother, otherwise a large number of sick and disabled people will be left behind, which will easily cause large-scale diseases. Pay attention to getting rid of the sick and disabled.

3. Choose appropriate chemicals to prevent and treat diseases scientifically.

Use of smoke generating agent:

During this period, diseases with low temperature and high humidity were the main diseases. If you take precautions, you can consider smog. Because the smoke is simple to use, does not increase humidity, and the medicine is evenly dispersed, it is suitable for use in foggy days, but we must pay attention to the weather forecast to ensure that the tuyere can be opened the next day. As for the types of smoke agents, chlorothalonil can be used to control most fungal diseases, and procymidone, iprodione and other smoke agents can also be considered to control gray mold and Sclerotinia sclerotiorum. It also has a certain effect on some leaf spot diseases.

Preparation of organic copper:

Due to the high humidity, water film will appear on the leaves, leading to tomato canker and bacterial rash. Therefore, we can consider using copper clothianidin (Mycobacterium bronchisepticum), copper succinate (DT), copper rosin acid, copper nitrohumate and other organic copper preparations to prevent bacterial diseases, and copper can also prevent fungal diseases. I would like to remind you that it is best not to choose inorganic copper preparation, because inorganic copper preparation releases copper ions relatively quickly in rainy days.

Leaf spot diseases such as tomato early blight are caused by higher fungi, so azoxystrobin+triazole can be considered.

4, after a sunny day, pay attention to prevent flash seedlings and sunburn.

In continuous foggy days, plants will have certain adjustment ability to adapt to adverse environment. However, if the weather is clear and sunny after the rain, the light in the greenhouse will be strengthened and the temperature will rise, but the soil temperature will rise relatively slowly. So it is easy to flash seedlings and get sunburned in the sun. Therefore, it is suggested that you should pay attention to shading at noon after sunny days. You can use shading nets or reduce the grass felt by one third, so that crops can gradually adapt to this process.