Bactericides are generally classified into protective fungicides, systemic therapeutic fungicides, and eradication fungicides. Many fruit farmers and even some farmers technicians in the process of choosing pesticide fungicides for apple orchards, due to the lack of comprehensive understanding of pesticide fungicides, although the number of medications is quite large, but the effect of disease prevention and treatment is not satisfactory, not only increase the orchard Pesticide investment, and increased the resistance of the bacteria. Therefore, it is necessary to further clarify the prevention and control mechanism of pesticide fungicides, to achieve scientific classification, reasonable selection, and standardized use. 1 Types and characteristics of commonly used pesticide fungicides 1.1 Protective fungicide After use, a layer of gas-permeable, water-permeable and light-transmitting dense protective film is formed on the surface of the leaves and fruits of the tree. This protective film can inhibit the germination and invasion of the spores of the bacteria, thereby achieving the purpose of sterilization and disease prevention. Mostly, it is a broad-spectrum pesticide fungicide, which can destroy the activity of various enzymes of physiological metabolism of bacteria, has many effects on germs, is not easy to produce drug resistance, and an agent can prevent and cure various diseases. It mainly includes mancozeb pesticide disinfectants, mineral source protectants and copper preparations. 1) Mancozeb pesticide disinfectant. The sterilization range is wide, generally no drug resistance occurs, mainly to control the infection of pathogens, to control rust on fruit trees, early defoliation, anthracnose and so on. It is usually used in various periods before the occurrence of the disease and after the control of the bacteria. Commonly used products are Mancozeb, Dasheng M-45, Spray, Yibao, Xinwansheng, BAK, Cobo and so on. 2) Mineral source type protective agent. It is a selective bactericidal, acaricidal and insecticide . Its active ingredient is sulfur, which plays a major role in protection. It can control a variety of fungal diseases such as rot, anthracnose, powdery mildew, rust, etc., and is effective against larvae and nymphs of wintering worms and scale insects. Commonly used products are sulfur, stone sulfur, crystal stone sulfur, polysulfide, sulfur suspension and so on. 3) Copper preparations. This is a good plant protection agent. Its active ingredient is copper ion. It has good control effect on fungi and bacteria. It has repellent effect on various pests. It can prevent anthracnose, powdery mildew, brown spot, rust and black. A variety of diseases such as star disease and bacterial ulcer disease. Mainly Bordeaux liquid, similar products are basic copper sulfate, green depot, green milk copper and so on. 1.2 systemic therapeutic pesticide fungicide After use, it can penetrate into the tree or be absorbed by the tree body and then conduct in the body, directly affecting the pathogen or affecting plant metabolism, killing or inhibiting the pathogenic process of the pathogen, clearing and alleviating the disease, and its action point is relatively simple and can only be destroyed. The activity of one or two kinds of enzymes is easy to produce drug resistance. It mainly includes agricultural antibiotics, organic heterocyclic preparations (benzimidazoles and thioureas, etc.). 1) Agricultural antibiotics. It has strong systemic action and can be absorbed by the roots of the tree and run upwards, and can penetrate into the leaves, but it has no bactericidal effect. It mainly has a strong inhibitory effect on plant pathogenic bacteria, and can cause germs spore germination tubes and hyphae. The end is swollen into a spherical shape, loses the ability to invade, inhibits the elongation of hyphae, hinders the formation of hyphae, sclerotia and lesions, and has good control effects on the branches and leaves of fruit trees. For the early or early stage of the disease. Commonly used products are agricultural anti-120, polymycin, polyoxomycin, pluriticmycin, Baolian, polyoxane, Jinggangmycin and so on. 2) Organic heterocyclic preparations. The systemic action is strong, and it has special effects on fungal ascomycetes and basidiomycetes, and some are also effective against semi-known bacteria, and are generally used in various stages of disease occurrence or fruit growth. Commonly used products are methyl thiophanate (methylthiocarbazone), carbendazim, triadimefon (pustrin), diniconazole (speed Poly), Fuxing, Shigao, myclobutanil, myclobutanil + mancozeb Zinc, iprodione, terazos and the like. 1.3 eradicative pesticide fungicide The most commonly used products are peroxyacetic acid products. When the bacteria are exposed to peroxyacetic acid, they will produce strong reducibility, forcing the decomposition of peracetic acid, producing strong oxidation, rapidly oxidizing the bacteria into inactive substances, and the sterilization is thorough and rapid. The best non-polluting drug to replace arsenic. Indications of rot disease, ring disease, anthrax and so on. Commonly used products are chlorophyllin, 9281, fungus, and carbendazim. 2 Reasonable choice, standard use 1) When the leaves are frozen in autumn and winter and in the early spring, the ground and branches of the orchard are sprayed with anti-bacterial fungicides, which can completely kill various wintering bacteria of fruit trees and reduce the number of diseases in the current year. In the prevention and treatment of rot disease, the therapeutic effect of peracetic acid products is extremely obvious, the cure rate is 85% to 90%, and the disease healing is fast. After about 20 days of treatment, fresh healing tissue can be clearly seen. At the same time, in this period, the mineral source type protective agent is sprayed on the branches, and while protecting the tree body, the wintering cockroaches and cockroaches in the branches and rough cracks can be effectively controlled. Because the mineral source type protective agent is easy to cause phytotoxicity when the temperature is higher than 32 °C, the control effect is too bad when it is lower than 4 °C. Therefore, it is safer and effective only after defoliation in autumn and winter and before germination in early spring. 2) In the prevention and control of fruit trees during the growing season, in order to prevent the infection of the bacteria before the occurrence of the disease, the protective pesticide fungicide should be selected for prevention and protection; if the bacteria has invaded or the fruit tree has already developed, the systemic therapeutic fungicide should be used. To treat and control the spread and spread of the disease. After the pathogen is controlled, a protective fungicide is used. Specifically, in the prevention and treatment of one year, protective fungicides should be used in the early stage to protect against prevention. In the lighter years of the disease, the protective pesticide fungicide is generally used to better control the disease; in the middle and late stages of the heavier year, the systemic therapeutic fungicide is used for prevention, control and remediation. 3) It is not possible to use a single pesticide bactericide, preferably 2 to 3 pesticide bactericides. For example, after apple Xiehua is the infection period or the onset period of various diseases such as apple ring disease, spotted leaf disease, anthracnose disease, etc., if only a systemic therapeutic fungicide such as methyl thiophanate or carbendazim is selected, only Prevention and control of ring rot disease, anthracnose disease, can not prevent spot defoliation; if agricultural antibiotics or iprodione is selected, it can only prevent spot defoliation, can not effectively prevent ring rot and anthracnose, and add protective fungicide, then Play a role in protection and treatment. At the same time, in addition to the prevention and treatment of the above diseases, it can also treat a variety of other diseases. Triadimefone is a first-generation triazole pesticide fungicide, mainly for controlling fruit tree rust and self-pollination; diniconazole is a second-generation triazole fungicide, in addition to controlling fruit tree rust and powdery mildew, it also controls black spot disease. And early defoliation; Fuxing, Shigao, Xinsheng, Xiansheng and other third-generation triazole fungicides, although the control object is the same as the second generation, but its systemic, permeability, and dispersibility are better than the first 2 generations. 4) In the prevention and control of fruit tree diseases , it should be based on the principle of protective pesticide fungicides and the use of systemic therapeutic fungicides. Based on the prevention and prevention, comprehensive prevention and treatment can not be treated after the onset of illness. When the disease is particularly severe, it is difficult to control the disease even if a systemic therapeutic fungicide is used. Therefore, prevention must be the mainstay, scientific choice, and comprehensive prevention. Metal Warehouse,Metal Frame Warehouse,Prefab Metal Frame Warehouse,Metal Structural Warehouse Foshan Shengbang Steel Structure Co.,Ltd , https://www.sbsstructure.com