What are the characteristics of smoke generating agent?

A pesticide preparation, in which the active ingredients are suspended in a dispersion system similar to smoke after the smoke is ignited. Powdered mixture (fineness of which passes through 80 mesh sieve) made of pesticides, fuels (various carbohydrates such as sawdust and starch), oxidants (also known as combustion improvers such as potassium chlorate and potassium nitrate) and flame retardants (such as clay and talcum powder). Bags or cans are made of kraft paper containing potassium nitrate, and some of them have fuses inserted on them. It can burn after ignition, but it should only smoke without flame. The effective components of pesticides are vaporized by heating, cooled in air and condensed into solid particles with a diameter of 0. 1 ~ 2 microns. Smoke particles deposited on plants not only have good contact and stomach toxicity to pests, but also tiny smoke particles in the air can enter insects through the respiratory tract of pests, resulting in toxic effects. The use of fuming agent also has the advantages of high working efficiency and low labor intensity. As mentioned in the first section of this chapter, the application of smoke agent is greatly influenced by natural environment, especially airflow, and is generally suitable for pest control in places with large plant coverage or closed space, such as forests, warehouses and protected areas. The disadvantage of using smoke agent in farmland is that the "smoke cloud" disappears when it floats. This defect can be overcome to some extent if the smoke particles formed in the smoke agent formula can be properly enlarged. According to the test, add appropriate amount of anthracene, calcium carbonate, magnesium carbonate, etc. Smoking agent tends to make smoke particles bigger, which may be related to the fact that when substances and smoking agents are heated, they generate opposite charges with drugs, and the opposite charges attract each other to form larger smoke particle flocs. In China, closed protected cultivation has been promoted, and fungicides and fumigants have been widely used, such as chlorothalonil and procymidone. Pyrethroid insecticides and aerosols are also used.