柚木弯孢霉叶斑病菌生物学特性研究及对杀菌剂的敏感性测定

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

    • 摘要: 采用形态学鉴定结合rDNA-ITS 序列分析法、菌丝生长速率法和孢子萌发率法,对广西柚木上发生的弯孢霉叶斑病病原进行鉴定,并测定其生物学特性及对杀菌剂的敏感性。结果表明,柚木弯孢霉叶斑病的病原为Curvularia lunata(Wakker)Boed,其菌丝生长最适温度为27.5~30℃,产孢最适温度为30℃,而孢子萌发最适温度为35℃;光照不影响其菌丝生长,但对其产孢量有影响,24 h 黑暗处理最有利于其产孢,12h 光暗交替处理下该菌不产孢;菌丝生长和孢子萌发的最适pH 分别为5~10 和5;菌丝致死温度为54℃(20min),分生孢子萌发的致死温度为49℃(20 min);培养基PDA 有利于菌丝生长,PSA 有利于其产孢,但培养基Czapek 均不利于两者;该菌菌丝生长的最适碳源和氮源分别为麦芽糖和硝酸钾;对该菌抑菌效果最好的杀菌剂是咪鲜胺乳油,多·福的效果最差。该病害为柚木新纪录病害,病菌的生物学特性和对药剂的敏感性测定结果与前人研究结果存在一定差异。

       

      Abstract: 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.

       

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