With a service life of 4-6 years in general and up to 10 years, insect-proof nets are shaped like window screens, with resistance to UV, heat, water, corrosion, aging and high tensile strength, non-toxic and tasteless. They have the advantages of shade nets, but also overcome their shortcomings, worth being popularized.
I. Insect-proof nets' installation for greenhouses is very necessary, which can play a role in four aspects.
Basically vegetables can keep from cabbage worms, diamondback moths, aphids and other kinds of insect pests.
Covered with insect-proof nets, agricultural products can effectively keep from cabbage worms, diamondback moths, tobacco caterpillars, striped flea beetles, daikon leaf beetles, aphids and other pests. According to the test, the effectiveness of the net against cabbage worms, diamondback moths, cowpea moths and American leaf miners is 94-97%, and its effectiveness against aphid is 90%.
Virus transmission can bring disastrous consequences to greenhouse cultivation, especially aphids transmission. But insect-proof nets can cut off the transmission of diseases by pests, greatly reducing the incidence of viral disease, with about 80% control efficacy.
The test showed that in July and August, covered with the 25-mesh white insect-proof nets, the temperature in the morning and evening is the same as the open field, while the noon on a sunny day is about 1℃ lower than the open field. In March and April, the temperature in these nets is 1-2℃ higher than that in the open field, and the 5cm ground temperature is 0.5-1℃ higher than that in the open field, which can effectively protect against frost. In addition, these nets can block part of the rain from falling into the greenhouses, reduce the humidity in the field, decrease the disease, and reduce the evaporation of water in the greenhouses on sunny days.
The strong light in summer will inhibit the nutritional growth of vegetables, especially leafy vegetables. While insect-proof nets can play a certain role in shading and generally the shading rate of 20-22 mesh silver gray nets is 20-25%.