黄脉爵床棒孢霉叶斑病病原菌及其生物学特性鉴定

明确黄脉爵床棒孢霉叶斑病病原菌及其生物学特性,为防控提供理论依据。通过病原菌分离、形态特征观察、致病性测定、rDNA-ITS序列分析、生物学特性及寄主范围测定等研究,证明该病病原菌为山扁豆生棒孢Corynespora cassiicola;菌丝生长及产孢适宜温度20℃～28℃,孢子萌发适宜温度24℃～32℃,菌丝致死温度49℃处理10 min;菌丝生长适宜pH 6～10,产孢适宜pH 4～8,孢子萌发最适pH 8;光暗交替适合菌丝生长与产孢,连续光照可抑制菌丝生长;菌丝生长量由少到多培养基顺序为CA、PCA、PDA、CMA、OA,而PDA上产孢最多;刺伤接种,病菌可侵染喜树(Camptotheca acuminata)等植物。黄脉爵床棒孢霉叶斑病病原为山扁豆生棒孢C.cassiicola,病菌易产孢,寄主广,潜育期短。该病菌侵染黄脉爵床为首次报道。

Identification and biological characteristics of Corynespora cassiicola causing leaf spot on Sanchezia nobilis

Appropriate spacing present experiment was conducted to clarify species and biological characteristics of Corynespora leaf spot pathogen isolated from Sanchezia nobilis. Based on pathogen isolation, morphological characteristics observation, pathogenicity test, analysis of rDNA-ITS sequence, biological characteristic test, and host range examination, the Senchezia nobilis Corynespora leaf spot pathogen was identified as Corynespora cassiicola. The suitable temperature for mycelial growth and sporulation of C. cassiicola ranged from 20℃ to 28℃. The suitable temperature for spore germination of C. cassiicola ranged from 24℃ to 32℃. The lethal temperature for mycelial growth was 50℃ for 10 min. The suitable pHs for mycelial growth and sporulation ranged from 6 to 10 and from 4 to 8, respectively. The optimum pH for spore germination was 8. Alternation of light and darkness was beneficial for mycelial growth and sporulation. Continuous illumination inhibited the mycelial growth. The order of media suitable for mycelial growth were CA, PCA, PDA, CMA and OA in sequence. PDA was the most suitable medium for sporulation. The pathogen could infect multiple plant species such as Camptotheca acuminate and Hibiscus rosa-sinensis under wound inoculation conditions. The pathogen could easily produce conidia on common media without specific environmental requirements, and showed a wide host range and a short latent period of infection. This is the first report of Corynespora cassiicola causing leaf spot on Sanchezia nobilis.