Pyrethrin is prepared by solvent method. It is a perennial root plant, pyrethroin (mainly found in flowers) is a typical nerve agent, in which the main components are pyrethroin I and, isolated by L. Luzica and H. Staudinger in 1924. It has the effect of touch, killing, gastric toxicity and repellent, and can play a role in the peripheral nervous system, central nervous system and other organs. Strong knockdown force on pests, wide insecticidal spectrum, low use concentration, low toxicity to people and livestock, safety to plants and environment.

            Matters needing attention :⑴ pyrethrin light is easy to decompose, the spraying time is best selected in the evening. ⑵ Pyrethroin should not be mixed with alkaline pesticides such as sulfur mixture, Bordeaux fluid, and resin mixture. ⑶ Commercial preparations should be kept in a closed container to avoid high temperature, humidity and direct sunlight. ⑷ pyrerum is a powerful touch killing agent, the agent must contact the insect body to be effective, otherwise the effect is not good.