         At present, in the comprehensive prevention and control of pests, chemical control still occupies a very important position. Grasping the mechanism of action of different fungicides, control spectrum, mode of action and resistance risk and resistance mechanism is the important guarantee for the scientific use of bactericides in disease prevention and control, and delay the drug resistance of pathogens. Chemical agent is a broad concept, in addition to the role of antibacterial bactericidal agents, but also includes some plant immune activator and plant pesticides, different control measures and different types of agents reasonable use are significance of the disease for the prevention and treatment of quality, efficiency And the reduction of chemical agents.
         May be a lot of farmers have found that some of the effective fungicides are more and more weak on the disease control now  , which is because the people lack the scientific use of pesticide technology, the phenomenon of pesticide abuse, the future need to strengthen the national confrontation Drug management of this link.
         It is generally believed that the bactericidal spectrum of a class of compounds (such as triazole fungicides, methacrylic acid ester fungicides) that are similar in chemical structure may be the same, but in practice it has been found that the same product bactericidal spectrum in the same fungicide There will be a big difference. Therefore, to determine a new compound of the control object, must be through rigorous biological activity test to confirm, and can not simply analogize the existing similar products sterilization spectrum. At the same time, the study also found that some fungicides, although the compound structure is different, but its role in the pathogen in the same target, the use of these two agents or after the use of rotation, but will accelerate the emergence of drug resistance, In the production to avoid these errors.
          To carry out the new drug resistance risk assessment, combined with drug resistance mechanism and mechanism of action and other research results, the development of field science crop disease management program, the rational use of pharmaceutical rotation and scientific compound have a very important role to guide the pesticide enterprise product promotion and Delay the production of resistance and resistance to governance .