How to manage fruit trees in greenhouses in rainy and hazy days

Since November this year, all parts of the country will experience low temperature, rain and snow, and severe smog. Due to continuous rainy, snow, and haze weather, it has extremely adverse effects on the production of fruit trees in greenhouses. In order to minimize the impact of rainy, haze and adverse weather, the reporter recently interviewed Wang Guishen, a technical instructor of the Ministry of Agriculture and Rural Affairs. He specially puts forward the following management suggestions:

Humidity management of fruit trees in greenhouse

The humidity in the greenhouse should be maintained at 60-75%, which is conducive to its budding. If the humidity is too high, ventilate in time. Interval ventilation can be implemented, each interval is about 2 hours, and each ventilation time is 30 minutes. If the haze is severe and the humidity outside the shed is significantly higher than that in the shed, do not let the wind blow. Starting at 10 am, the vents will be closed until 16 pm. At the same time, control the watering. Generally, water once after the shed is buckled. Generally, do not water during the flowering period. After watering, you can cover the silver film to control humidity, increase the ground temperature and improve the light in the shed. If the soil is severely dry during the flowering period, water should be watered under the mulch.

Temperature management of fruit trees in greenhouse

Although due to the influence of haze weather, there is insufficient sunlight in the shed, but due to the recent rapid rise in temperature, the current temperature management in the shed is still mainly controlled. If the temperature is too high and the temperature is too high, it will cause the fruit trees to sprout quickly and bloom slowly, and the phenomenon of first bud and then flower is easy to appear, which makes the leaf buds preferentially compete for storage nutrients, resulting in lower fruit setting rate and early shedding of young fruits. Therefore, the temperature should increase slowly during this period, and keep it for 2-3 days for every 2-3°C increase, and then increase gradually. Finally, keep the highest temperature not to exceed 28℃, and the lowest temperature at night is about 10℃.

Do a good job in light management of fruit trees in greenhouses

Due to insufficient light in continuous cloudy days, it has a negative impact on the normal growth of the tree, especially the normal flowering. Therefore, the tree body lighting should be increased as much as possible. Even if you encounter extreme cold weather, you should take advantage of the high noon temperature to see more light. The coverings on the shed should be peeled and covered frequently, not only to add light, but also to keep warm. And clean the debris on the shed in time. At the same time lay reflective film in the shed. Prevent the tree from being hungry due to insufficient light to photosynthesize. When the temperature rises rapidly at noon after a long period of cloudy to sunny, attention should be paid to the proper "return to the curtain" to prevent discomfort in the tree.

Strengthen fertilizer and water management

In the greenhouse, watering and nitrogen fertilizer application should be controlled to enhance the tree body's ability to prevent overgrowth and reduce the occurrence of diseases and insect pests. When the weather turns fine, the tree can be properly topdressed according to the growth of the tree. Phosphorus and potassium fertilizers are the main topdressing, and a small amount of urea is added. In order to improve the efficiency of photosynthesis, CO2 gas fertilizer can be added in the shed to increase the CO2 concentration.

Pest Control

The main pests and diseases of fruit trees in the greenhouse are aphids, red spiders, leaf miners and perforation disease, scab, anthracnose, root cancer and so on. Especially pay attention to the advance prevention of diseases. To control Myzus persicae, spray with 70% imidacloprid 4000 times solution in the early stage of bud germination. To control red spiders, use Mite Dijing or Nissoran 2500 times liquid. To prevent leaf miners, spray with dichlorbendon 3 or emamectin benzoate 3000 times. To prevent perforation, scab, and anthracnose, spray 80% tebuconazole 5000 times solution and 5% chlorobromoisocyanuric acid 3000 times solution when the flower is red, and spray 2% Ningnanmycin 1000 times before the fruit is ripe liquid. To prevent and cure root cancer diseases, use Genailing 400 times to irrigate roots.

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