Pesticide formulation pesticide
1. powder (D)
Powder is the most widely used dosage form in the early period of the founding of new China. The powder is easy to be manufactured and used. It is mixed and crushed with raw materials and inert fillers (talc, clay, Gaoling clay, diatomaceous earth, acid clay etc.) in a certain proportion to make the fineness of the fineness reach a certain standard. The standard of our country is that 95% of the powder can be screened by 200 targets, that is, the diameter of the powder is below 74 microns, and the average particle size is about 30 microns. The commonly used standard of powder in foreign countries is that 98% of the powder can pass through 325 mesh screens, the maximum diameter of the powder is 44 microns, and the particle size is 5? 15 microns. However, the fineness of powder is closely related to its efficacy. The powder with a particle size greater than 37 microns has poor efficacy and the most effective particle diameter is below 20 microns. Therefore, the quality problem of powder processing is urgent to be solved in China. Powder is popular with people in arid or mountainous areas where water is difficult. Because it is easy to use and does not need water, it can be directly sprayed on crops with a simple duster, and has high work efficiency, little adhesion to crops and less residue. It is not easy to cause phytotoxicity. In addition to direct for dusting, but also dressing, soil treatment, preparation of bait granule and the prevention and treatment of diseases, insects and rodents in the grass. The powder should be carried out in the early and late crop foliage is wet or dew, because the silt on the surface of crops mainly rely on the role of deposition attachment or electrostatic adsorption, but its adhesion is very small, in the crop water on the surface of membrane, adhesion of particles is improved, can improve the control effect. The disadvantage of powder is that when used, particles with diameter less than 10 microns are easily lost and wasted due to the influence of surface air flow. They also cause environmental pollution and affect people's health. At the same time, when processing, the dust is much, and it has great influence on the health of the operator. But for the closed environment of greenhouses and greenhouse for dusting control diseases and insect pests, can make full use of fine powder in the air floating movement ability and role, can make the plant leaves are on the rear, evenly drug deposition, improve the control effect, but not on the outside of the greenhouse environment pollution. The use of powder is a better method of spraying in greenhouse and greenhouse.