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Tobacco brown spot, Tobacco early blight, Tobacco grey spot, Tobacco grey mold, Tobacco southern stem and root rot were collected from Nanping, Sanming, Longyan of Fujian province during 2009~2011, and the pathogens were conformed by symptoms observation, pathogens isolation and pathogenicity test, they were Alternaria longipes, A. solani, A. tenuissima, Botrytis cinerea and Sclerotium rolfsii, and the biological characteristics of these five diseases were systematically investigated for further research and better control of them. Biological characteristic results of these five diseases showed that 4~36℃was fit for the mycelia growth of A. longipes, but the optimum temperature was 30℃, and the optimum temperature for A. solani, A. tenuissima B. cinerea and S. rolfsii were 24℃, 28℃, 22℃, 34℃; the optimum pH of the mycelia growth for A. solani, A. tenuissima, B. cinerea and S. rolfsii were 6.0, 6.0, 5.0 and 7.0; the PDA was the best medium for mycelia growth of these five diseases, but Sodium tartaric medium was not fit for the mycelial growth of A. longipes, A. solani and B. cinerea, and NaNO2 was not fit for S. rolfsii; the continuous illumination was benefit for the mycelia growth of A. longipes, A. solani, A. tenuissima and fit for S. rolfsii to form sclerotium, while it had no significant effect on B. cinerea, S. rolfsii , the continuous darkness was advantage for mycelia growth of B. cinerea, S. rolfsii, but it had inhibitory action on A. longipes and A. solani, and no significant effect on A. tenuissima; UV irradiation on B. cinerea, S. rolfsii have certain inhibitory effect on their mycelial growth, increasing the UV irradiation time can reduce the formation of sclerotium of S. rolfsii; the optimum C/N is 20:1 for these five diseases. Study on host range of B. cinerea, the inoculation test showed that the leaves of Cucumis sativus, Solanum lycopersicum, Brassica oleracea, B. chinensis, Celosia cristata could be infected by B. cinerea, and Vigna unguiculata could not be infected.
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