Fungicide action method and method of use Fungicide is a type of agent used to prevent and control plant diseases. All agents that have a killing effect on pathogens or inhibit growth but do not hinder the normal growth of plants are collectively called fungicides. There are two modes of action: one is a protective fungicide, and the other is a systemic fungicide. The protective fungicide directly contacts the pathogenic bacteria outside or on the surface of the plant to kill or inhibit the pathogenic bacteria so that they cannot enter the plant, thereby protecting the plant from the hazards of the pathogenic bacteria. This type of fungicide is called a protective fungicide, and its role has two aspects: one is to directly contact the pathogenic bacteria after the agent is sprayed, which is "contact bactericidal effect"; the other is to spray the agent on the surface of the plant In the above, when the pathogenic colony is poisoned by the agent on the plant body, it is called "residual bactericidal effect".