Insect-proof net is like window screen, with high tensile strength, UV resistance, heat resistance, water resistance, corrosion resistance, aging resistance and other properties, non-toxic and tasteless, the service life is generally 4-6 years, up to 10 years. It not only has the advantages of shading nets, but also overcomes the shortcomings of shading nets, and it is worthy of vigorous promotion.
1. It is very necessary to install insect-proof nets in greenhouses. It has six functions:
1. Effective against insects.
After covering the insect net, it can basically avoid a variety of pests such as cabbage caterpillars, diamondback moths, and aphids.
After agricultural products are covered with insect-proof nets, it can effectively avoid the damage of various pests such as cabbage caterpillars, diamondback moths, cabbage armyworms, Spodoptera litura, flea beetles, simian leaf beetles, aphids and so on. According to the test, the insect control net is 94-97% effective against cabbage cabbage caterpillars, diamondback moth, cowpea pod borer and Liriomyza sativa, and 90% against aphids.
2. Prevention of viral diseases.
Virus transmission can have disastrous consequences for greenhouse cultivation, especially by aphids. However, after the installation of the insect-proof net in the greenhouse, the transmission of the pests is cut off, which greatly reduces the incidence of viral diseases, and the control effect is about 80%.
3. Adjust the temperature, soil temperature and humidity.
In the hot season, the greenhouse is covered with a white insect-proof net. The test shows that: in the hot July-August, in the 25-mesh white insect-proof net, the temperature in the morning and evening is the same as the open field, and the temperature is about 1 ℃ lower than the open field at noon on a sunny day.
From March to April in early spring, the temperature in the shed covered by the insect-proof net is 1-2°C higher than that in the open field, and the temperature in the 5 cm ground is 0.5-1°C higher than that in the open field, which can effectively prevent frost. In addition, the insect-proof net can block part of the rainwater from falling into the shed, reduce the humidity in the field, reduce the incidence of disease, and reduce the evaporation of water in the greenhouse on sunny days.
4. Has shading effect.
In summer, the light intensity is large, and the strong light will inhibit the vegetative growth of crops, especially leafy crops, and the insect-proof net can play a certain role in shading. The 20-22 mesh silver-gray insect-proof net generally has a shading rate of 20-25%.
5. Prevent fruit drop.
The ripening period of the fruit is in the rainy weather in summer. If the insect-proof net is used to cover it, it will reduce the fruit drop caused by the rainstorm during the ripening period of the fruit, especially in the years when the fruit of dragon fruit, blueberry and bayberry suffer from heavy rain during the ripening period. The effect of reducing the fruit drop is more obvious .
6. Prevent frost.
If it is in the low temperature season at the young fruit stage and fruit maturity stage, it is easy to cause chilling damage or freezing damage. The use of insect-proof net covering is not only conducive to improving the temperature and humidity in the net, but also uses the isolation of the insect-proof net to prevent frost damage on the fruit surface.