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1. The mesh number, color and width of the screen shall be considered when selecting the insect proof screen for the greenhouse

If the mesh number is too small and the mesh size is too large, the pest control effect will not be achieved; In addition, if the number is too large and the mesh is too small, it can prevent insects, but the ventilation is poor, resulting in high temperature and too much shading, which is not conducive to crop growth.

For example, in autumn, many pests began to move to the shed, especially some moth and butterfly pests. Because of the large size of these pests, vegetable farmers can use insect control nets with relatively small mesh, such as 30-60 mesh insect control nets.

However, if there are many weeds and whiteflies outside the shed, it is necessary to prevent whiteflies from entering through the hole of the insect control net according to their smaller size. It is recommended that vegetable farmers use a dense insect control net, such as 40-60 mesh.

For example, the key to the prevention and control of tomato yellow leaf curl virus (TY) is to select qualified insect resistant nylon gauze. Under normal circumstances, 40 mesh nylon gauze mesh is enough to prevent tobacco whitefly. Too dense ventilation is not good, and it is difficult to cool down at night in the shed after planting. However, the mesh of the mesh produced in the current mesh market is rectangular. The narrow side of the mesh of the 40 mesh mesh can reach more than 30 meshes, and the wide side is often only more than 20 meshes, which cannot meet the requirements of stopping whitefly. Therefore, only 50~60 mesh mesh can be used to stop whitefly.

In spring and autumn, the temperature is low and the light is weak, so white insect proof net should be selected. In summer, in order to give consideration to shading and cooling, black or silver gray insect proof net should be selected. In areas where aphids and viral diseases are serious, silver gray insect prevention nets should be used to drive away aphids and prevent viral diseases.

2. When selecting the insect proof net, pay attention to check whether the insect proof net is complete

Some vegetable farmers report that many newly bought insect proof nets have holes, so they remind vegetable farmers to expand the insect proof nets when purchasing and check whether the insect proof nets have holes.