Insect screen can prevent insects from entering the greenhouse, and it is usually installed at the air inlet, window, doorway and other openings. The mesh size of insect control net should be able to prevent insects from entering. The installation of insect screen will increase the local resistance of the vent, which should be considered in the estimation of greenhouse ventilation.
According to the crops planted in the greenhouse, the season of using the net and the objects to be protected, the mesh size of the net should be selected. The mesh is too large to have the desired effect; the mesh is too small to have good effect, but the ventilation resistance increases. In order to achieve a good effect of insect control, there is a corresponding relationship between the mesh size and the insect size of the insect control net. The insect control net should be selected according to the insect species to be prevented. Several factors should be taken into consideration when choosing insect control net.
The natural habits of insect invasion should be clear about the time of occurrence of insect pest, whether it occurs in the whole growth cycle of crops or in a short time. If the pest only occurs in a short period of crop growth cycle, we can consider a cheap and slightly poor quality insect control network.
It is necessary to consider the insect species that may be damaged, and different kinds of insects may invade in different seasons. In the case of many kinds of pests, we should choose the insect net with good quality, high strength and resistance to pests. Insect species should compare the mesh size of insect prevention net with that of insect, and determine the mesh size of insect prevention net according to the smallest insect species to be prevented.