Environmental protection is a very important issue in agricultural production in recent years. Physical control of pests and diseases is becoming more and more popular under the trend of emphasizing the transformation of agricultural production mode. Many greenhouse farmers choose to install insect-proof nets, which is economical and practical, and also meets the requirements of ecological agriculture, reducing the damage of pesticides to soil and crops. What I want to introduce today is the knowledge about insect-proof nets.
Why install insect-proof nets?
1. Effective pest control. After covering the insect control net, the insect pests such as cabbage caterpillar, diamondback moth and aphid can be basically eliminated. Agricultural products covered with insect control net can effectively avoid the damage of many pests such as cabbage caterpillar, diamondback moth, cabbage armyworm, Spodoptera litura, yellow curl beetle, ape leaf insect, aphid and so on. According to the experiment, the control effect of insect control net on cabbage caterpillar, diamondback moth, cowpea pod borer and Liriomyza sativae was 94-97%, and the control effect on aphids was 90%.
2. It can prevent diseases. Virus transmission will bring disastrous consequences to greenhouse cultivation, especially aphid transmission. However, after installing the insect-proof net in greenhouse, the transmission route of insect pests was cut off, and the incidence of viral diseases was greatly reduced. The control effect was about 80%.
3. Adjust temperature, soil temperature and humidity. In the hot season, the greenhouse greenhouse was covered with white insect-proof net. The experiment showed that the temperature in the morning and evening of 25 mesh white insect-proof net was the same as that in the open field during the hot July-August period, and the temperature in the sunny noon was about 1 C lower than that in the open field. From March to April in early spring, the temperature in shelter covered with insect-proof net was 1-2 C higher than that in open field, and the temperature in 5 cm was 0.5-1 C higher than that in open field, which could effectively prevent frost. In addition, insect-proof net can prevent part of rainwater from falling into the shed, reduce the field humidity, reduce the incidence of disease, and reduce the evaporation of water in the shed on sunny days.
4. Shading effect. In summer, strong light can inhibit vegetable vegetable nutritional growth, especially leafy vegetable. Insect-proof net can play a certain role in shading. The shading rate of 20-22 mesh silver-gray insect-proof net is 20-25%.
Insect-proof net is like window screen, with high tensile strength, anti-ultraviolet, heat, water, corrosion, aging 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 sunshade net, but also overcomes the shortcomings of sunshade net. Therefore, it is worth promoting vigorously. Then the question arises: What kind of insect-proof net should we choose?
Model selection
In autumn, many insect pests begin to migrate to the shed, especially some moths and butterflies. Because of the large size of these pests, vegetable farmers can use relatively few insect control nets, such as 30-60 mesh insect control nets. But for more weeds and whitefly outside the shed, we should prevent whitefly from entering the hole of the insect control net according to its smaller size. It is suggested that vegetable farmers use a denser insect control net, such as 40-60 purpose.
Color selection
For example, thrips have a strong preference for blue. It is easy to attract thrips outside the shed to the surrounding area by using blue insect-proof net. Once the insect-proof net is not covered properly, a large number of thrips will enter the shed and cause harm. When using white insect-proof net, this phenomenon will not occur in the shed, but when used in conjunction with sunshade net, to choose. White is the best choice. A silver-gray insect-proof net has better repellent effect on aphids. The black insect-proof net has obvious shading effect and is not suitable for use in winter or even cloudy days.
In general, in spring and autumn season, compared with summer, the temperature is lower and the light is weaker, so white insect control net should be chosen; in summer, black or silver-gray insect control net should be chosen to take account of both shading and cooling; in areas where aphids and viral diseases occur seriously, silver-gray insect control net should be chosen to avoid aphids and prevent viral diseases.