Important functions of Fungicide
There are two ways of action of fungicides: one is a protective fungicide, and the other is a systemic fungicide. The protective fungicide directly contacts the pathogenic bacteria in vitro or on the surface of the plant, killing or inhibiting the pathogenic bacteria, making it unable to enter the plant, thereby protecting the plant from the pathogen. These fungicides are called protective fungicides. They have two functions: one is to contact the pathogen after spraying, and directly kill the pathogen, that is, "contact sterilization"; the other is to spray the agent on the surface of the plant. In the above, when the pathogenic colony is exposed to the agent on the plant body and is poisoned, it is called "residual bactericidal effect".
Different fungicides work differently. It is called a protective fungicide, that is, a protective agent, which is applied to the surface of plants before the infection of the pathogen; it can eliminate the infected bacteria at the application site, and is called a scavenging fungicide; it can be absorbed by plants and The system is called a systemic fungicide, which is also a systemic fungicide. Many scavengers are also systemic. Most of them have chemotherapeutic effects. Therefore, it is often practical to simply separate the bactericide into two modes of action: protective and systemic. Their mechanism of action can also be broadly divided into two categories:
1. Interfere with the respiratory process of pathogens and inhibit the production of energy.
2. Interfering with the biosynthesis of living organisms such as proteins, nucleic acids, and sterols. Most of the protective fungicides are products with a wide spectrum of sterilization and low bactericidal power. Systemic fungicides generally have stronger bactericidal power and narrower bactericidal spectrum, and some of them have specific toxicity to certain pathogens. Since the action point of the systemic agent in the bacteria is relatively simple, the pathogen is easily resistant by mutation of the genetic gene. In order to avoid or delay the occurrence of drug resistance, it is usually possible to select a suitable protective agent and a systemic agent to be mixed or rotated, so that a long and short complement can be obtained to obtain a better control effect. In the use, various application methods such as seed treatment, foliar spray and soil treatment should be adopted according to the characteristics of the disease occurrence.
