Study On The Identification And Biological Characteristics On The Pathogens Of The Three Diseases Of Hippeastrum Hybridum

The leaf blight,red spot disease and leaf spot are three serious diseases in the process of cultivation of the Hippeastrum,which are caused serious influence to the ornamental and economic value of the Hippeastrum.In this paper,pathogens causing the three kinds of diseases above were separated and identified,preliminary research on biological characteristics of the three pathogens was carried on,and the sensitivity to 11 kinds of different fungicides were tested.The main research results are as follows:1.Accroding to Koch’s Postulation test,combined with morphological identification and molecular identification,the pathogens of leaf blight,red spot disease and leaf spot on Hippeastrum are attributed to Fusarium oxysporum,Colletotrichum hippeastri and Curvularia geniculata.2.For Fusarium oxysporum,the suitable temperature range of mycelial growth was 8~36℃,and the best optimum temperature of the mycelial growth,sporulation and conidial germination are the same temperature 28℃.The lethal temperature of mycelia and spores were 60℃ maintaining 10 min.The p H value range of mycelia growth and sporulation was p H2 to p H12,and the p H value range of conidial germination was p H3 to p H11.The best optimum p H value of the mycelial growth,sporulation and conidial germination was p H6,p H6 and p H7 respectively.Light has no effect on mycelial growth,but unfavorable to sporulation and conidial germination.Among all the tested carbon source,glucose,maltose,mannitol and lactose could promote the mycelial growth and sporulation.The glucose was the most conducive to the mycelial growth,and mannitol is most conducive to sporulation.In addition to trisodium citrate the remaining seven kinds of carbon sources are conducive to the sporulation,and glucose was the most conducive to the conidial germination.Among all the tested nitrogen source,urea and sodium nitrite was the most conducive to the mycelial growth.Urea,sodium nitrite and L-lysine was the most conducive to the sporulation,and urea and sodium nitrite could promote the conidial germination,but the effect was not obvious.Among the selected 11 kinds of fungicides,mycelia growth and sporulation were completely inhibited by sulphur·carbendazim,mancozeb,tebuconazole,oxime·tebuconazole,carbendazim·thiram,myclobutanil·thiram.3.For Colletotrichum hippeastri,the suitable temperature range of mycelial growth,sporulation and conidial germination were 8℃ to 32℃,10℃ to 30℃ and 10℃ to 32℃respectively,and the best optimum temperature of the mycelial growth,sporulation and conidial germination were the same temperature 24℃.The lethal temperature of mycelia and spores were 55℃ maintaining 10 min.The p H value range of mycelia growth,sporulation and conidial germination were p H2 to p H12,p H3 to p H12 and p H3 to p H11 respectively.The best optimum p H value of the mycelial growth,sporulation and conidial germination was p H6,p H6 and p H7 respectively.Light has no effect on mycelial growth,and the constant dark conditions were conducive to sporulation and conidial germination.All of 8 kinds of carbon sources were against the mycelial growth and sporulation,and only lactose and fructose could promote conidial germination.All of 7 kinds of tested nitrogen sources could promote the mycelial growth and sporulation,and only sodium nitrate and ammonium hydrogen phosphate could promote the conidial germination.Among the selected 11 kinds of fungicides,mycelia growth and sporulation were completely inhibited by sulphur·carbendazim,difenoconazole,metalaxyl-M·mancozeb,mancozeb,tebuconazole,oxime·tebuconazole,carbendazim·thiram,myclobutanil·thiram.4.For Curvularia geniculata,the suitable temperature range of mycelial growth was 10~34℃,and the suitable temperature range of sporulation and conidial germination were the same temperature 12~34℃.The best optimum temperature of the mycelial growth,sporulation and conidial germination are 28℃,28℃ and 30℃ respectively.The lethal temperature of mycelia and spores were 60℃ and 55℃ maintaining 10 min respectively.The p H value range of mycelia growth,sporulation both were p H2 to p H12,and the p H value range of conidial germination were p H3 to p H1.The best optimum p H value of the mycelial growth,sporulation and conidial germination were p H6,p H7 and p H7 respectively.The constant dark conditions were conducive to the mycelial growth,sporulation and conidial germination.Among all the tested carbon source,mannitol and maltose could promote the mycelial growth.In addition to trisodium citrate the remaining seven kinds of carbon sources are conducive to the sporulation,and mannitol showed best.Fructose and mannitol has the effect to promote the conidial germination,but no significant effect of promoting.Among seven kind of the tested nitrogen source,urea and diammonium hydrogen phosphate were conducive to the mycelial growth.Sodium nitrite and L-lysine were conducive to the sporulation,but the effect of L-lysine was not obvious.All of seven kinds of the tested nitrogen source were against the conidial germination.Among the selected 11 kinds of fungicides,mycelia growth and sporulation were completely inhibited by metalaxyl-M·mancozeb,mancozeb,tebuconazole,oxime·tebuconazole,carbendazim·thiram,myclobutanil·thiram,and the inhibiting rate was 100%.