Micro-ecological Analysis Greenhouse Cucumber Fusarium Wilt In Fuzhou

Ecological environment, disease species and occurrence regularity of greenhouse cucumber were investigated Fujian Huangshan Chaoda Modern Agriculture (Holdings) Limited farm. Micro-ecological enviroment of greenhouse cucumber Fusarium wilt was systematically studied, and micro-ecological control technique was preliminarily investigated.1. Relationship between greenhouse eco-environment and cucumber Fusarium wiltTemperature and humidity: the temperature reached about 10℃in February and the maximum relative humidity of day and night could reach 90% or more, even at 100% in night. The low temperature and high humidity led to the early outbreak of Fusarium wilt of cucumber in greenhouse.Soils: As sandy soil cultivation measures usually be used in cultivation of greenhouse cucumber, the Fusarium wilt of cucumber become more serious with increasing soil sand.Pathogens: Fusarium oxysporum accumulated year by year accompanying cropping greenhouse cultivation measures. Root wound caused by incognita is more conducive to cucumber wilt infection.2. Changes in micro-ecological of cucumber under the stress of cucumber wiltThe number of rhizosphere microbe was changed at different growth stages in infected cucumbers. In the germination stage, the number of rhizosphere bacteria of infected cucumber was less than that of normal cucumbers. In fruiting stage stage, the number of rhizosphere fungi and actinomycetes from infected cucumbers was less than that of healthy cucumbers. During the micro-ecological balance stage of cucumber rhizosphere, bacteria played a major role in early stage, but fungi and actinomycetes played majors roles in later stage.According to fungi morphology, 35 species of filamentous fungi and 6 species of yeast were identified from different niches of cucumber. 25 species were identified from the rhizosphere of cucumber. Fusarium sp.., Penicillium sp.., and Trichoderma sp.. were dominant rhizosphere fungi. The infected cucumber had fewer rhizosphere fungi than that of healthly cucumbers. In the flower stage, when cucumber wilt outbroke at its peak, the diversity of rhizosphere fungi was declined to its lowest level. On the root vascular of infected cucumber, Fusarium sp. was the dominant strain and had few species. On the leaf surface of infected cucumber, Trichoderma sp. was the dominant strain. On the surface of flower and fruit of infected cucumber, yeast was the dominant strain and the infected cucumber had more species than normal cucumber.According to actinomycetes morphology, 15 species were identified from the rhizosphere of cucumber. Streptomyces sp. .and Sprocket sp. .were dominant in normal. Contemporarily, Streptomyces sp.. was dominant in infected rhizosphere of cucumber in early stage and Sprocket sp. was isolated in late stage.According to bacterium morphology, physiological and biochemical, and 16S rDNA sequence, 9 bacterial species were isolated and identified from cucumber rhizosphere in greenhouse. Bacillus,Pseudomonas,Bacteroidetes,Empedobacter,Proteus were dominant strains. The number of isolated bacterium species in infected rhizosphere was less than that of normal rhizosphere. Cultured-independent molecular technique was used to analyze the microbial diversity of cucumber rhizosphere soil. There were Fusarisum oxysporum infection rhizosphere soil, Meloidogyne incognita infection rhizosphere soil, complex infection by Meloidogyne incognita and Fusarisum oxysporum rhizosphere soil and normal soil inside and outside greenhouse. Based on denaturing gradient gel electrophoresis (DGGE), Pseudomonas was the dominant bacterium, except complex infected by Meloidogyne incognita and Fusarisum oxysporum. Compared with the normal, the infected had higher diversity index and smaller species eveness by T-RFLP and PCR-DGGE.The quantity of Nitrite bacteria, Nitrobacteria, Cellulose-utilizing bacteria, Ammonifying bacteria and Sulphate reducer decreased in the rhizosphere of infected Fusarisum oxysporum cucumber respectively, but the quantity of Denitrifier, Desulphate reducer increased respectively. Change was unstable to erobic azotobacter in infected Fusarisum oxysporum. There was greater decrease in fall stubble than spring crop. Under Fusarium oxysporum stress, the activity of Catelase, Urease, Cellulase, Phosphatase were declined respectively.3. Technology of micro-ecological control of cucumber Fusarium wilt in greenhouse 2 fungi, 2 bacterium, and 2 actinomycetes were selected from isolated microbe by confrontation to Fusarium oxysporum between the culture plate respectively. They were Empedobacter brevis sp., Bacillus megaterium sp., Chainia sp. , Sprocket sp. , Trichoderma sp., Cephalosporium sp. . The cooperative between antagonistic Trichoderma and antagonistic bacterium was ineffective, the same as that between antagonistic Cephalosporium sp. and antagonistic bacterium. Certain antagonistic effect was found between antagonistic Chainia sp. and Empedobacter brevis sp., the same antagonistic effect as between antagonistic Sprocket sp. and Empedobacter brevis sp. . Other antagonistic strains could be collaborative culture. Selected antagonistic strains Trichoderma sp., Bacillus megaterium sp. , Chainia sp. were studied on fermentation conditions by shaker respectively, accessing to a large number of conditions. The conditions for Chainia sp. fermentation were explored .But for fermentation bubbles, the fermentation parameters were needed to further optimize. By root injury treatment with Fusarium oxysporum, the result showed that prevention was more effective than remedy in pot inoculation test.