What Is Bactericidal?
Fungicides are also known as biocides, bactericidal algicides, microbicides, etc., and generally refer to chemical agents that can effectively control or kill microorganisms in the water system-bacteria, fungi and algae. In the international arena, it is generally used as a generic term for agents used to control various types of pathogenic microorganisms.
- Chinese name
- Fungicide
- Foreign name
- Industrial Bactericide
- Pinyin
- sha jun ji
- Definition
- Agents for controlling various pathogenic microorganisms
- Classification
- Bactericide, virus killer, algicide
- Opening event
- Using organic mercury compounds to control wheat smut
- Ingredients
- Inorganic compounds
- Mode of action
- Protective fungicide
- Fungicides are also known as biocides, bactericidal algicides, microbicides, etc., and generally refer to chemical agents that can effectively control or kill microorganisms in the water system-bacteria, fungi and algae. In the international arena, it is generally used as a generic term for agents used to control various types of pathogenic microorganisms.
Background of fungicides
- According to surveys, there are more than 80,000 species of pathogenic microorganisms (fungi, strong bacteria, rickettsia, mycoplasma, viruses, algae, etc.) harmful to plants worldwide. Plant diseases have caused huge losses to agriculture, and crops around the world have reduced their average annual yield by about 500 Mt. There have been many times in the history of severe famine caused by the epidemic of certain plant diseases, and even a large number of people starved to death. The use of fungicides is a cost-effective method for controlling plant diseases.
Main types of fungicides
- Fungicides are also known as biocides, bactericidal algicides, microbicides, etc., and generally refer to chemical agents that can effectively control or kill microorganisms in the water system-bacteria, fungi and algae. It is mainly divided into agricultural fungicides and industrial fungicides.
Agricultural fungicide
- It is a type of pesticide used to control plant diseases caused by various pathogenic microorganisms, and generally refers to fungicides. However, internationally, it is generally used as a generic term for agents that control various types of pathogenic microorganisms. With the development of fungicides, bactericides, virus killers, algicides and other subclasses are distinguished.
Industrial fungicides
- Oxidative sterilization
- Fungicide
- Fungicides are classified according to their source. Except for agricultural antibiotics, which are biologically-derived fungicides, the main species are chemical synthetic fungicides. Fungicides are a class of agents used to control plant diseases. Any agent that has a killing effect on the pathogen or inhibits growth but does not hinder the normal growth of the plant is collectively referred to as a fungicide. Fungicides can be classified according to their mode of action, source of raw materials, and chemical composition.
Fungicides by application area
- Divided into two kinds of industrial fungicides and agricultural fungicides according to the application field.
Fungicides are divided according to the raw material source of the fungicide
Biocide
- Such as sulfur powder,
- Fungicide
Organic sulfur fungicide
- Such as ammonium, sodium dirust, fumezine, zirconium, mancozeb, fumezine and so on.
Organophosphorus and arsenic fungicides
- Such as rice blast net, gram blast powder, ethidium aluminum, methyl cumulant, bacteriostatic, rice foot green and so on.
Fungicides replace benzene fungicides
- Such as methyl tolbutin, chlorothalonil, dicotrim, pentachloronitrobenzene and so on.
Azole fungicides
- Such as Fenru Ning, Carbendazim, Moxacillus, Benconazole, Thicarbin and so on.
Fungicides
- Jinggangmycin, polyoxin, kasugamycin, agricultural streptomycin, antimycin 120, etc.
Fungicide
- Such as Feiweiwei, Shuangxiaoling, Anthracnose Fume, Antiviral Alum M8, Metalaxyl Copper, DT Fungicide, Metalaxyl · Manganese-Zinc, Seed Dressing · Manganese-Zinc, Methylthiobendazim · Manganese-Zinc, Widely Sterilized Milk powder, metalaxyl-Fumei Shuang wettable powder.
Other fungicides
- Such as metalaxyl, sclerotinia, humilis, hydrazone, sterilized dan, kelendazol, tefulin, dicarbendazim, rhizopus, formalin, high lipid film, bacteriotoxin, Propadicarb, quinacridone, dimethomorph · manganese zinc, etc.
Fungicides are classified according to how they are used
Fungicide protective agent
- Protective agent: Before the pathogenic microorganisms do not come into contact with the plant or immerse them in the plant body, treat the plant or the surrounding environment with the agent to achieve the inhibition of the germination of the pathogenic spores or the killing of the germinated pathogenic spores in order to protect the plant from its damage. effect. An agent having such an effect is a protective agent. Such as Bordeaux solution, zinc substitute, copper sulfate, green milk copper, zinc substitute manganese, chlorothalonil and so on.
Fungicides
- The therapeutic agent pathogenic microorganism has been immersed in the plant, but the plant manifests a disease in a latent period. The drug infiltrates from the plant epidermis into the inside of the plant tissue, and is killed or inhibited by the transmission, diffusion, or production of metabolites, so that the diseased plant is no longer harmed and the health is restored. An agent having such a therapeutic effect is called a therapeutic agent or a chemotherapeutic agent. Such as methyl tolbutin, carbendazim, kasugamycin and so on.
- 3. Eradication agent refers to the application of pesticides that can directly kill pathogens that have invaded plants. An agent having such an eradication action is an eradication agent. Such as Fumei arsenic, sodium pentachlorophenol, stone sulfur mixture and so on.
Fungicides are classified by conduction characteristics
Systemic fungicide
- Systemic fungicides can be absorbed into plant bodies by plant leaves, stems, roots, and seeds, and can be transmitted, diffused, retained, or metabolized by plant body fluids, which can prevent some diseases that penetrate into the plant or within the endosperm of the seed to protect the crop. It is not affected by pathogens or treats infected plants, so it has a therapeutic and protective effect. Such as Carbendazim, Lectobacillus, Lvheng No. 2, Carbendazim, Phytophthoracin, Thiobacillus, Metalaxyl, Ethylphosphine, Methyltobutzine, Dixon, Fenoxin, Metalaxyl Copper, and Antiviral Alum , Double seed dressing.
Non-systemic fungicide
- Non-systemic fungicide means that the agent cannot be systemically absorbed, conducted and retained by the plant. Most varieties are non-systemic fungicides. Such agents are not easy to cause resistance to pathogens and are relatively economical, but most of them only have a protective effect and cannot prevent diseases that penetrate into the plant. Such as zinc sulfate, copper sulfate, dodine, chlorothalonil, green milk copper, surfactants, synergists, sulfur mixtures, plant ash, Bordeaux solution, mancozeb, fomesal, chlorothalonil and so on. In addition, fungicides can be classified according to the use method, such as seed treatment agents, soil disinfectants, spraying agents and so on.
Protective fungicide
- There are mainly the following categories: sulfur and inorganic sulfur compounds, such as sulfur suspending agents, solid stone sulfur mixtures, etc .; copper preparations, mainly Bordeaux liquid, copper ammonia mixture, etc .; organic sulfur compounds, such as Fumei Shuang, Daisen Zinc, Daisen Ammonium, mancozeb, etc .; ammonium phthalimide, such as ketotan, dichlorvan, and sterilant, etc .; antibiotics, such as Jinggangmycin, blasticidin, polyoxin, etc .; other classes, such as Ye Kuling, Ye Kujing, chlorothalonil, Hesui Ning, etc.
History of fungicides
- Early bactericides were inorganic compounds, such as sulfur powder and copper preparations (see Bordeaux Solution), which are still used today. In 1914, I. Riem of Germany first used organic mercury compounds to control wheat smut, marking the beginning of the development of organic fungicides.
- In 1934, WH Tisdale and others in the United States discovered the bactericidal properties of dimethyldithiocarbamate, after which organic fungicides began to develop rapidly. In the 1950s and 1950s, there were three main series of organic sulfur fungicides: Fome, Daisen (such as Daisen Zinc), and trichloromethylthiodimethylcarboximide. In addition, organic chlorine, organic mercury, Organic arsenic fungicides have also been developed. Most of these fungicides are protective agents and have limitations in application.
- Since the 1960s, more chemical types of fungicides have continuously appeared, the most important of which is the advent of systemic fungicides.
- In 1965, Japan developed the organophosphate fungicide rice blast net, in 1966 the United States developed rust-proof spirit, in the United States in 1967, Benzendazol, in Japan in 1969, Thiopenthrin, in 1974, the Federal Republic of Germany, azoxystrobin, and Tricyclazole was developed in the United States, metalaxyl in Switzerland in 1977, and aluminum triethyl phosphate in France in 1978. The systemic agent represented by the above has become the mainstream of fungicide development since the 1970s. At the same time, agricultural antibiotics have also developed rapidly. Organic mercury, organic arsenic, and some organochlorine fungicides are being phased out due to toxicity or environmental pollution issues. The new generation of systemic agents has further expanded the market for bactericides due to improved control effects. By the 1980s, there were more than 200 species of fungicides. According to surveys, worldwide sales of fungicides reached US $ 2.54 billion in 1985, accounting for 18.4% of total pesticide sales.
- In 1984, sales of systemic agents in fungicides accounted for 44.2%, and non-systemic agents accounted for 55.8%. For nearly half a century, the development of fungicides has mainly focused on the prevention and treatment of fungal diseases, while the research and development of the prevention and treatment of bacterial and virus-induced diseases has been insufficient. China has mainly developed protective fungicides since the 1950s. Since the 1970s, it has started to develop systemic fungicides and agricultural antibiotics, and stopped using organic mercury agents. Because the application technology of fungicides is relatively complicated, the development speed is not as fast as pesticides, but the role of fungicides in increasing agricultural production has been increasingly recognized by farmers. With the modernization of Chinese agriculture, the development of fungicides will surely accelerate. Instructions
Fungicide operation method
- There are many ways to use fungicides, and each use method is designed according to the law of disease occurrence. The common use methods are: spraying on the ground crops in the field, disinfecting the soil and disinfecting the bacteria.
- For field crop spraying, the factors that affect the field disease prevention effect of fungicides are nothing more than three aspects of pesticides, environment, and crops, but the application technology of fungicides is more demanding than that of pesticides and herbicides, especially It is necessary to fully understand the occurrence and development of diseases, because the occurrence and development of diseases are not as clear as insects and grasses.
- Pay attention to two points when spraying field crops: first is the type and concentration of the pesticide. The choice of the type of medicine depends on the type of disease, so a correct diagnosis of the disease type must be made before the right medicine can be prescribed. For example, rice blast can be selected from rice blast net, rice blast spirit, tricyclazole, etc .; wheat powdery mildew, rust should be selected from triazolol, triazolone, etc .; However, it should also be noted that if the same disease occurs on different crops, sometimes the same agent cannot be used. For example, Bordeaux solution can prevent downy mildew, but it is easy to cause damage to cabbage, so it is not suitable to control downy mildew of cabbage. After selecting the type of agent, the appropriate application concentration should be selected according to the type of crop and growth period, the type and formulation of fungicide, and environmental conditions.
- Methods to improve the effect of fungicides:
- Reasonable concentration
- Regardless of whether it is a water or wettable powder drug, it needs to be diluted with water before spraying. Different concentrations of bactericides are required, so the ratios must be strictly followed according to the instructions. A reasonable concentration is more conducive to the effectiveness of the bactericides. If the ratio is arbitrarily, too high a concentration will cause phytotoxicity to the crops; too low a concentration will not meet the control requirements.
- Suitable spraying time
- The time of spraying the fungicide has a direct relationship with the control effect. Premature spraying will cause waste of the drug and reduce the control effect; too late the pathogen has caused harm to the crop. Therefore, it is necessary to take medicines in a timely manner according to the occurrence of different diseases, predictions and specific conditions. In general, the time of administration of the bactericide can be selected before or at the beginning of the onset.
- Improve medication quality
- The quality of bactericides used includes the number of drugs used, the number of times used and the quality of sprays. The amount of medicine should be appropriate. Too much medicine will increase the cost and cause harm, and too little medicine will not achieve the effect of prevention and control. Therefore, increase or decrease according to the specific situation. The number of doses can be determined by the residual period of the agent and the weather conditions. Generally, it is sprayed every 10-15 days for a total of 2-3 sprays. In case of rain after application, make up spray. The method of improving the quality of the medicine is to spray the fog point evenly and finely, spraying the stems and leaves of the plants.
- Prevent phytotoxicity
- There are many reasons for bactericidal damage caused by fungicides, which are affected by the medicament itself, different crop sensitivities, crop growth stages and climatic conditions. In general, medicines and crops with higher water solubility have a greater chance of causing harm in the seedling stage and booting flowering stage, high temperature and drought, fog weight and high humidity, and so need to be handled with caution. [1]
Important fungicide functions
- New Jieer
- Different fungicides work differently. Protective fungicides that are applied to the surface of a plant before they infect them are called protective fungicides, that is, protective agents; those that can destroy infected bacteria at the application site are called eradicative fungicides; they can be absorbed by plants and can Systemic bacteria are known as systemic fungicides, which are transmitted to the site where the germs infect. Therefore, in practice, fungicides are often simply divided into protective and systemic action modes. Their mechanism of action can also be roughly divided into two categories:
- 1. Interfering with the respiratory process of germs and inhibiting the production of energy.
- 2. Interfering with the biosynthesis of bacterial organisms such as proteins, nucleic acids, and sterols. Protective fungicides are mostly products with a broad bactericidal spectrum and low bactericidal power. Systemic fungicides generally have a strong bactericidal power and a narrow bactericidal spectrum. Some of these species have specific selective toxicity to certain pathogens. Because the systemic point of action of the systemic agent in the bacteria is relatively single, pathogens are susceptible to resistance due to mutations in genetic genes. In order to avoid or delay the development of drug resistance, an appropriate protective agent and a systemic agent can usually be selected for mixed application or rotation. This can be used to complement each other to obtain better control effects. According to the characteristics of disease occurrence, various application methods such as seed treatment, foliar spraying and soil treatment should be adopted during use.
Fungicide Industrial Application
Application of biocides in industrial circulating cooling water
- 1. Quaternary ammonium fungicides: dodecyldimethylbenzyl ammonium chloride, dodecyldimethylbenzylammonium bromide, tetradecyldimethylbenzylammonium chloride, polyquater Ammonium salts, etc.
- 2. Chlorine-containing bactericides: chlorine gas, chlorine dioxide, sodium dichloroisocyanurate (Ultrachloride), sodium trichloroisocyanurate, etc.
- 3. Peroxide fungicides: hydrogen peroxide, peroxyacetic acid, etc.
- 4, oxazoline: isothiazolinone, benzoisothiazolinone, etc.
- 5. Aldehydes: glutaraldehyde, etc.
Application of Fungicide in Waterborne Coating Industry
- Oxazoline: isothiazolinone, benzoisothiazolinone, etc.
Fungicide precautions
- General pesticide instruction manuals have recommended concentrations,
Fungicide determination method
- The insecticidal or bactericidal virulence of pharmaceuticals is often expressed as "lethal medium dose", that is, the median lethal dose (mg / kg) required to kill half (50%) of the biological population is often abbreviated as LD50. If the concentration represents a dose, it is the "lethal concentration", abbreviated as LC50. Bactericide is expressed by ED50 or EC50, which is the dose or concentration required to inhibit 50% of spore germination.
Fungicide spore germination assay
- Spray different chemical solutions on the surface of a glass slide or a plate, and quantify the spore suspension dropwise. After contacting the chemical solution, after a certain incubation time, inspect the percentage of spore germination under a microscope.
Bacteriostatic zone
- Mix the suspension of pathogenic spores or hyphae with the agar medium. After condensing, place a circular filter paper (about 6 mm in diameter) sterilized and dipped in different concentrations of the drug solution on the surface of the medium. After a period of time, due to the diffusion effect of the medicinal solution, the growth of germs is inhibited, that is, an "inhibition circle" is formed. The size of the inhibition circle is measured to compare the virulence of the fungicide.
Biocide growth rate assay
- In the method of adding a chemical solution to the agar medium and condensing the bacteria, after 24 to 48 hours, observe the growth of the colonies, calculate the growth rate, and compare the growth rate with the control group without the agent.
Development prospects of fungicides
- The market speed of pesticide active ingredients is now significantly slower than in the past. Among them, the rate of herbicide decline is the most obvious, and pesticides have also declined to a certain extent. However, the market introduction of new fungicide products has been very strong, especially in recent years.
- In 2009, there were a total of 17 new pesticides published worldwide, and 9 fungicides accounted for more than 50%. Among them, 3 were amide compounds, 3 were strobilurin compounds, and 1 was triazolopyrimidine. Compound, a quinoline compound, and an antiviral agent, fluorophosphine. During the "Eleventh Five-Year Plan" period, a total of 34 domestic pesticides with independent intellectual property rights obtained pesticide registration licenses, of which 17 were fungicides, occupying half of the country. The main varieties are flumorph, oxystrobin, pyracoxazole, Enoxime, aureus, etc.
- Reasons for Good Global Bactericide Production and Application Prospects
- 1. The degree of agricultural intensification has been continuously strengthened;
- 2. Frequent extreme weather has stimulated the demand of the fungicide market;
- 3. The demand for bactericides in the non-pesticide field continues to increase rapidly and the profit margin is large;
- 4. Some patents of high-efficiency fungicide varieties will expire during the "12th Five-Year Plan" period;
- 5. During the "Twelfth Five-Year Plan" period, the state will continue to increase technological innovation, and fungicide varieties with independent intellectual property rights will continue to be developed and put on the market;
- 6. The growing area of genetically modified crops will have a great negative impact on pesticides and herbicides, but will have little effect on fungicides.