2. The smaller contact Angle can greatly improve the spread of the liquid on the target. The liquid is sprayed on the leaf or the surface of insect pests. The contact Angle is directly related to the surface tension of the liquid. The greater the tension, the larger the contact Angle, and the worse the effect of the drug. If the contact Angle is less than 90 degrees, the liquid will not roll off generally, but when the contact Angle is greater than 90 degrees or above, the liquid will roll off when it is sprayed on the blade. Because of its very low surface tension, silicone can greatly reduce the contact Angle of the liquid sprayed on the surface of plant leaves and pests, so it can achieve better drug effect. Or to 2000 times diluted 0.5% methylaminoabamectin benzoate for example: directly diluted with water after the liquid, sprayed on the leaves of celery, rape, tomato, cabbage, green onion five crops, the contact Angle was 36.5 degrees, 39.6 degrees, 49.3 degrees, 93.6 degrees, 130.2 degrees; The contact angles between the above five crops and the drug solution were directly reduced to 33.2, 35.2, 35.1, 40 and 39.7 degrees, respectively, when the concentration of 0.05% organic silicon surfactant was added to the same drug solution. By comparing the results, there is no doubt that after adding the organic silicon surfactant, the drug liquid can spread and wet better on the crop leaves, thus greatly improving the drug effect.