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 can play four roles:
①It can effectively prevent 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, they 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 caterpillars, diamondback moth, cowpea pod borer and Liriomyza sativa, and 90% against aphids.
②It can prevent disease. 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 route of the pests is cut off, which greatly reduces the incidence of viral diseases, and the control effect is about 80%.
③Adjust the temperature, soil temperature and humidity. In the hot season, the greenhouse is covered with a white insect net. The test shows that: in the hot July-August, in the 25 mesh white insect control net, the temperature in the morning and evening is the same as that in the open field, and the temperature is about 1 °C 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 prevent 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.
④Has shading effect. In summer, the light intensity is large, and the strong light will inhibit the vegetative growth of vegetables, especially leafy vegetables, 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%.
2.the selection of insect nets need to pay attention to several issues:
At present, many farmers use 30-mesh insect-proof nets, and some farmers use 60-mesh insect-proof nets. At the same time, the colors of insect nets used by farmers are also black, brown, white, silver, and blue. So what kind of insect net is suitable?
First of all, choose insect nets reasonably according to the pests to be prevented.
Secondly, choose different colors of insect nets according to different needs.
Generally compared with summer in spring and autumn, when the temperature is lower and the light is weaker, white insect-proof nets should be used; in summer, black or silver-gray insect-proof nets should be used in order to take into account the shading and cooling; in areas with serious aphids and virus diseases, in order to drive To avoid aphids and prevent virus diseases, silver-gray insect nets should be used.
Again, when choosing an insect-proof net, you should also pay attention to check whether the insect-proof net is complete.
However, it is recommended that when used alone, brown and silver-gray should be selected, and when used in conjunction with sunshade nets, silver-gray and white should be selected, and the mesh is generally 40-60 mesh.