Research Progress of Biological Control Techniques in Plant Disease Control

Because chemical pesticides have the advantages of high control efficiency, high speed, wide insecticidal and antibacterial spectrum, low cost, and ease of use, they have become a major means of preventing pests and diseases from capturing harvest in agricultural production. However, the long-term use of large quantities of chemical pesticides can easily cause soil degradation, environmental pollution, and pathogen resistance. Biological control is non-toxic, harmless, non-polluting, non-resistive and highly effective. It not only meets people's demand for green food, but also provides guarantee for the sustainable development of agriculture. As a result, the research, development, and application of biological control were mentioned on the agenda, and they were valued by governments of all countries. There are a wide variety of biocontrol bacteria, and fungicides, bacteria, actinomycetes and viruses are widely used in production. The fungi include Trichoderma, Chaetomium, yeast, P. lilacinus, Verticillium spores, mycorrhizal fungi, etc. The bacteria mainly include Bacillus, Pseudomonas, and other plant growth-promoting bacteria (PGPR). Radioactive soil Agrobacterium and Pasteurella etc. Actinomycetes are mainly Streptomyces and its variants; Attenuated strains of viruses; Non-pathogenic mutant strains of pathogenic bacteria.
1 Development and utilization of biocontrol fungus 1.1 Trichoderma fungal fungus Trichoderma spp. is a resource-rich biocontrol fungus in the soil. It has important biological control value and has a promising future. It can parasitize 29 plant pathogenic bacteria in 18 genera. Antifungals can be measured using a plant disease detector. The most common are Trichoderma harzianum, Trichoderma viridis, Trichoderma viridis, Trichoderma longibrachiatum, Trichoderma koningii, and green fungal mold. They are widely found on the surfaces of soil and plant diseases, seeds and bulbs. People applied Trichoderma spp. to control Sclerotinia sclerotiorum, pepper whitefly disease, tobacco black shank disease, watermelon wilt disease, rice sheath blight, and grape gray mold. Trichoderma has received much attention since its development and development. There are many molding preparations. For example, ECOFIDE, which is based on T. viride, has been used in India to control a variety of soil-borne diseases in field crops and vegetables. Yang contract statistics, etc. In 1997, there were 11 registered Trichoderma preparations at home and abroad, including 5 H. harzianum strains, 1 strain of Trichoderma spp., 2 Trichoderma viride strains, and 3 other Trichoderma strains.
1.2 There are more than 300 species of Chaetomium in the genus Chaetomium, which can prevent blight of grain seedlings, cane damping-off, reduce the incidence of tomato blight and apple spot disease, and Rhizoctonia solani, Brassica oleracea Phytophthora, genus genus, genus Botrytis, botrytis and their genus Alternaria pathogens also have a certain inhibitory effect.
1.3 Yeast Yeast is mainly used for the prevention and treatment of post-harvest diseases in fruits and vegetables. Fan Qing et al. believe that the use of a suspension of Trichosporon spp. can completely inhibit the occurrence of Botrytis cinerea and Penicilliosis. In addition, yeast can also antagonize E. amylovora and B. cinerea.
1.4 Paecilomyces lilacinus, Verticillium verticilliformis, and Arthrobactrum fungus nodules Fungi mainly include A. robustus, A. irrigularis, A. conoides, A. oligospora and A. dactyloidea. Liu Xingzhong et al. used the culture materials of Paecilomyces lilacinus in the specimen storage tool series to apply soil to the soybean cyst nematode for 2 to 3 years, resulting in a large number of empty cysts. Lin Maosong et al. controlled the egg parasitism efficiency of southern root-knot nematode with Verticillium spores to 90.8%.
1.5 Mycorrhizal fungi Mycorrhizal fungi can effectively increase the absorption of phosphorus and nitrogen by plants, especially under adverse conditions, and can increase the disease resistance of plants. The inoculation of mycorrhizal fungi showed that the inoculated plants significantly increased the photosynthetic rate of the leaves, increased the dry matter quality of the plants or increased the amount of microorganisms in the soil, improved the microecological environment of the root zone soil, and accumulated the nutrient basis for the growth of the next generation crops.
2 Development and utilization of biocontrol bacteria At present, biocontrol bacteria used for plant disease control mainly include Bacillus, Pseudomonas, Agrobacterium and Pasteurella.
2.1 Plant growth-promoting rhizobacteria (PGPR)
PGPR, as a class of biocontrol bacteria with the most potential for disease prevention and application, can not only promote plant growth, increase crop yield, but also increase disease prevention capacity. Therefore, it has become a hot topic for many scholars. At present, the most studied are Pseudomonas and Bacillus.
Among a wide variety of rhizosphere beneficial bacteria, Pseudomonasspp. is a type of bacteria that has been extensively studied. Due to its unique advantages of simple nutritional requirements, rapid propagation, and strong rhizosphere colonization, it has been the most studied and reported for more than 20 years, proving that it has the most potential for prevention and application. At present, there are many studies on Pseudomonas fluorescence, P.syringae, P. cepacia, and P. pitida. After Xu Tingquan et al. treated seeds of cucumber with Pseudomonas M18, the incidence of cucumber wilt disease decreased by 70% to 80%. Bacillus (Bacillus), due to its fast growth and simple nutrient requirements, can form spores with high resistance to stress, and have inhibitory or control effects against many pathogens and diseases caused by them. Currently used for the biological control of plant diseases are mainly B. subtilis and B. cereus. To date, a variety of bacterial strains have been successfully developed into products and promoted.
2.2 Radioactive Soil Agrobacterium
The genus was studied earlier. The earliest strain used for biological control was the Agrobacterium radiobacter K84 strain for the prevention and treatment of peach root cancer. Genetic engineering strain K1026 was obtained through restriction enzyme digestion and DNA recombination to increase the disease-preventing effect.
2.3 pasteurella (Pasteurella) Pasteurella because of its resistant endospore, easy to attach the nematode body wall and infestation of nematodes, parasites can produce a large number of spores again to achieve infection and stable performance by the plant science The family’s favor became another germicide for nematode control. In addition, endogenous bacteria can also be used to inhibit certain bacteria that cause frost damage and reduce the occurrence of frost damage.
3 actinomycetes (Actinomycetes) the development of the use of actinomycetes is the most widely used Streptomyces and its variants, there are many molding formulations used in production, such as the wellmycin, endotherapy, 768, S-921, Nongkang 120, etc., can be used to control poplar rot rot, botrytis, black spot cucumber, phytophthora capsici, cotton Verticillium dahlia, Rhizoctonia solani and tomato early blight, gray mold, cabbage black rot And cabbage soft rot bacteria. In the future, based on the definition of its effective ingredients, an efficient microbial agent should be developed.
4 Development and utilization of pathogen-free pathogenic strains Regardless of fungal, bacterial or actinomycete pathogens, natural mutations or induced mutations will produce some non-pathogenic strains that can be used for biological control.
5 The attenuated strain of the virus has been used for the production of a viral attenuated strain or satellite RNA to prevent viral diseases. Such as the use of N14 to control tomato mosaic disease; Potato spindle tuber virus mild strains to prevent PSV and the use of satellite RNA added to the formation of CMV attenuated vaccines CMV 5-51 and S12, respectively, for large-scale control of TMV and CMV.

Building Hoist

Construction lifts are usually used in combination with tower cranes on the construction site. The general load is 0.3-3.6 tons, and the operating speed is 1-96m/min. There are many types, which can be divided into two types according to the operation mode: non-paired weight and paired weight.

Construction elevator is often used in the construction of manned cargo construction machinery, mainly used in the city high-rise and super high-rise in all kinds of buildings, also known as construction elevator.

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