Insect net is a new type of agricultural covering mater […]
Insect net is a new type of agricultural covering material that emerges after the agricultural film and rain cover. It is made of high-quality polyethylene with anti-aging, anti-ultraviolet and other chemical additives. It is drawn by wire drawing and looks like window screen. It has the characteristics of tensile, heat resistance, water resistance, corrosion resistance, non-toxic and tasteless. In addition to the advantages of the shade net, the vegetable insect net has the biggest feature of preventing insects and preventing diseases and greatly reducing the amount of pesticides used. It is the key technology for pollution-free vegetables. The introduction of this new technology in Zhenjiang City in 1995 has been extended to 18 provinces and cities nationwide and has achieved remarkable economic, social and ecological benefits. At present, pollution-free vegetables produced by insect-resistant nets in cities such as Nanjing and Shanghai are particularly favored by the public.
First, the principle of pest control and disease prevention of insect nets
The insect-proof net uses artificially constructed barriers to reject pests outside the net to achieve the purpose of preventing insects, preventing diseases and keeping vegetables. In addition, the light reflected and refracted by the insect net has a certain repellent effect on pests.
Second, the role of insect nets
1. Insect-proofing. After the vegetables cover the insect-repellent net, they can basically eliminate the pests such as cabbage caterpillar, diamondback moth, cabbage moth, Spodoptera litura, yellow-curved beetle, locust leafhopper, and aphid. According to the test, the control effect of the insect-proof net on cabbage cabbage was 96%, the control effect of Plutella xylostella was 94%, the control effect on Viburnum chinensis was 97%, and the control effect of Liriomyza sativa was 95%. More than 90.
2. Anti-viral Virus disease is a catastrophic disease on a variety of vegetables, mainly caused by insects, especially aphids. Since the insect net has cut off the main transmission route of pests, it greatly reduces the infection of vegetable viruses. According to the test, after covering the insect net, the control effect of spring tomato virus disease was 88.5%, the yield increased by 24%, the control effect of cabbage virus was 79%, and the yield increased by 22%.
3. Adjusting the temperature and soil temperature Tests show that: in the hot July to August, in the 25-mesh white insect net, the morning and evening temperatures are flat with the open field, while the sunny noon is about 1 °C lower than the open ground. In the early spring from March to April, the insect-proof net covered the shed is 1~2°C higher than the exposed ground, and the 5cm ground temperature is 0.5~1°C higher than the open ground, which can effectively prevent frost.
4. Shading and temperature adjustment The opacity rate of the 25-mesh white insect-proof net is 15-20%. The relative humidity of the air inside the net is about 5% higher than that of the open ground, and about 10% higher after watering, which has a certain moisturizing effect.
5. Anti-storm, anti-strong wind After the rain hits the insect net, the precipitation decreased by 21.6%. It has become drizzle on the Internet, and the impact is weakened, which is conducive to the development and growth of vegetables. The wind speed in the insect net can be reduced by 15-20%, and it has better anti-typhoon effect.