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Fusarium Wilt (Fusarium oxysporum f. Sp. Niveum) is a devastating vascular soil-borne diseases, the wilt pathogen soil Xi ranks bacteria, highly resistant to adverse environmental capacity, it is difficult to prevention and treatment of the many ways in which people are increasingly turning to Biological Control. Actinomycetes as an important the biological pesticides resource bacteria much concern about and viable agents play an important role in the application process. Biocontrol agents on the environmental compatibility and safety advantages unmatched by traditional chemical pesticides, but it has many advantages, there are also a lot of problems and difficulties, such as soil complex and changing environment, a single inoculant control effect is not ideal presented in the application process push without wide phenomenon. Based on this consideration, for the good traits of biocontrol services in production, to play a greater space actinomycete biocontrol agents of disease prevention, improve control efficiency and stability of the watermelon wilt, wilt this study of biocontrol strain screening, fermentation conditions, colonization ability on the basis of the research, from the multi-strain combination of advantages complementary perspective to carry out multi-bacterial compound of traits of different strains of biocontrol, variable single agents actinomycetes combination of synergistic disease prevention, provides a theoretical basis for actinomycetes composite inocula feasibility of prevention and control of soil-borne diseases. 1 through the determination of the antibacterial activity of biocontrol actinomycetes bacteria colonization ability, first study the biocontrol activity of a single strain, the ability to reproduce, the growth rate, which screened three biocontrol agents with good traits: strain 153 growth and reproduction of fast, strong resistance, low nutritional needs; SC11 Fusarium fungus the relative the strongest antibacterial and resistant, and the ability to produce chitinase; SF6 endophyte promoting effect significant. Optimization shallow dish fermentation conditions to determine the best solid culture conditions: the three biocontrol actinomycetes best matrix formulation of 85% shrimp meal of rice, 12% wheat bran 3%; seed inoculation amount was 25% solution is the most appropriate ; SC11 best seed liquid strain age of 144 h, SF6 and 153 are 96 h; different optimal incubation time of different strains, including SC11, 153 for 9 days, SF6 is 8 days. In the optimization of culture conditions, not only to increase the bacterial count, accelerate the speed of growth and reproduction of the strains, biocontrol inhibition of target bacteria. 3 by a plate culture, heat treatment, ultraviolet treatment, and other method as screened inocula suitable carrier, wherein chitosan, a non-farming soil and crude chitin have a significant protective effect of the growth of Actinomycetes. The powder is mixed with a carrier, and 55 ± 2 ℃ heat storage after 7 days, to obtain a higher survival rate control to achieve a significant difference in the level of these three materials was chosen as a biocontrol composite preparations common carrier. 4 three biocontrol agents for complex, Exploration mixed powder the watermelon wilt control effect and watermelon plant growth promoting role. Pot experiment results show that the disease have a certain effect of disease prevention, of composite agents and 3 single strain of watermelon, and the most ideal combination effect SC11 153 SF6. Composite inocula control efficiency of 47.47%, significantly higher than the best single strain of anti-efficiency the SC11 (25.87%). Strains can be achieved through synergies between complementary advantages, play a more desirable biocontrol effect. Composite inocula watermelon plant growth promoting effect, can enhance plant growth, improve stress resistance and thus prevent disease.
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