Biological characteristics of pathogen of Tectona grandis curvalaria leaf spot and its sensitivity to fungicides

Identification，biological characteristics and sensitivity to fungicides of the pathogen of Tectona grandis curvalaria leaf spot were studied by the methods of by morphology identification combined with analysis of rDNA-ITS sequence，Mycelium growth velocity and conidia germination rate. The results showed that pathogen of Tectona grandis curvalaria leaf spot was Curvularia lunata（Wakker）Boed，the biological characteristics of the pathogen were as follows：the growth temperature for mycelia of C. lunata was 10-40℃ and the optimum temperature was 27.5-30℃；For the sporulation，the temperature was 15-35℃ and the optimum temperature was 35℃；For the conidial germination， the temperature was 10-45℃ and the optimum temperature was 35℃；Whether lighting or not had little effect on the mycelia growth of C. lunata，but the effect of lighting on its sporulation was obvious，that 24 h darkness in a day could promote the sporulation of C. lunata，but 12 h alternating light and darkness was not suitable for its sporulation. The pH for the mycelia growth of C. lunata was 2-12，the optimum pH was 5-10，and the pH for the conidial germination of C. lunata was 5-7，the optimum pH was 5；The lethal temperature for the mycelia was 54℃ in 20 min，and the lethal temperature for the conidial was 49℃ in 20 min；PDA medium and PSA medium were suitable for the mycelia growth and sporulation of C. lunata，respectively，but Czapek medium was not both conducive to the mycelia growth and sporulation；Maltose and potassium nitrate were the optimum carbon source and nitrogen source. The suppressive effect of Prochloraz on C. lunata was significant，but the suppressive effect of carbendazim-thiram-Xin Junan on C. lunata was worst among tested fungicides. The disease was a new recorded disease on T. grandis，there was a certain difference compared the results of biological characteristics of pathogen and their sensitivity to drugs determination with previous research.