Studying On Longan Fungus Disease I Guanxi

Fourteen pathogenic fungus were found in Guangxi according to investigationin few years.There were Marssonina dimocarpi Q.Wang et C.Y.Lai,Nimbya sp.,Alternaria alternata,Phyllosticta dimocarpi C.Y.Lai et Q.Wang,Bartaliniabischofiae Nag Raj,Fusarium oxysporum Schlecht,Pestalotiopsis paucisetaSacc,Pestalotiopsis paraguerienaisis Maubl.,Phomopsis guiyuan C.F.Zhang etP.K.Chi, Phomopsis longanae P.K.Chi et Z.D.Jiang, Ascochyta longan C.F.Zhang et P.K.Chi,Gloeosporium fructigenum Berk.,Colletotrichumgloeosporioides(Penz).Sacc.,Meliola Capensis(K.&C.)Theiss. var. DiplogtidisHansf.,Melida nepheliicola Stev.et Rold,respectively.In these pathogens,Nimbya sp.,Alternaria alternata Pestalotiopsis paucisetaSacc.,Pestalotiopsis paraguerienaisis Maubl.,Phomopsis guiyuan C.F.Zhang et P.K.Chi, Phomopsis longanae P.K.Chi et Z.D.Jian,Ascochyta longanC.F.Zhang et P.K.Chi were first report in Guangxi.Marssonina dimocarpi Q.Wang et C.Y.Lai and Phyllosticta dimocarpi C.Y.Lai et Q.Wang were new species,Bartalinia bischofiae Nag Raj was new record in China.The studying on the biological characters of Nimbya sp.and Alternaria alternata indicated:The range of colony growth both was 5～35℃,pH4～11,optimum at 28℃ and pH6～7.Two kinds of conidia germinate at range of 1O～35℃,RH≥75%,pH3～11,optimum at 28℃ and pH6～7.Nimbya sp.utilizated carbon sources optimum at D-sorbitol,the optimum nitrogen source was L-histidine.The optimum carbon sources of Alternaria alternata was glycerine and the optimum nitrogen source was aminoacetic acid.Bartalinia bischofiae Nag Raj:The colony growth range was 15～35℃,pH5～11,optimum at 25～28℃and pH7～9,the optimum carbon sources were Arabic gum power,soluble amylum,D-seminose etc,nutrate and ammomia were better utilizated as nitrogen source.Conidium produced germ-tube in water after 12 hours later.Germination range was 1O～35℃ and pH3～11,optimum at 25～28℃ and pH5～7.Germination can be promoted when 3% glucose water was used as germinal fluid.