摘 要：为明确湖南永州烟区烟草新叶斑病的致病菌及其分类地位，并结合室内毒力测定筛选出对其具有较好防治效果的化学杀菌剂，本研究从永州烟区采集烟叶，经组织培养、单孢分离纯化和离体接种，PCR扩增其ITS序列，经测序与系统发育分析，并结合菌落与孢子的形态特征分析鉴定病原菌；同时采用菌丝生长速率法测定了43%氟菌·肟菌酯（SC）等9种化学杀菌剂对该病原菌的室内毒力。室内毒力测定结果表明：43%氟菌·肟菌酯（SC）、70%甲基硫菌灵（WP）、42.4%唑醚·氟酰胺（SC）对多主棒孢霉（Corynespora cassiicola）的抑制效果最好，EC50分别为3.028 5、5.148 0、8.787 9 mg/L；其次是70%代森锰锌（WP）、75%肟菌酯·戊唑醇（WG）、32.5%苯甲·嘧菌酯（SC）和38%唑醚·啶酰菌（WG），EC50分别为21.844 3、31.841 8、32.080 1、41.867 6 mg/L；40%氯氟醚·吡唑酯（SC）和75%百菌清（WP）的抑制效果较差，EC50分别为192.466 9 mg/L和1 341.062 0 mg/L。本研究表明，永州烟草新叶斑病由多主棒孢霉引起，多主棒孢霉是烟草棒孢霉叶斑病的致病菌，甲氧基丙烯酸酯类和苯并咪唑类杀菌剂对其具有较好的抑制效果，本研究结果可为防治烟草棒孢霉叶斑病提供科学依据。

关键词：烟草；棒孢霉叶斑病；多主棒孢菌；室内毒力测定；杀菌剂
中图分类号：S432                        文献标志码：A        DOI：10.3969/j.issn.1007-7146.2026.01.006

Abstract: To identify the pathogen and its taxonomic status causing a new leaf spot disease in the Yongzhou tobacco-growing area of Hunan Province, and to screen effective control agents through laboratory toxicity assays, in this study, tobacco leaves were collected from the tobacco-growing regions of Yongzhou. The pathogen was isolated via tissue culture, single-spore isolation, and purification. Pathogenicity was confirmed through in vitro inoculation. The pathogen was identified by PCR amplification and sequencing of the ITS region, followed by phylogenetic analysis, combined with morphological characterization of colonies and spores. The indoor toxicity of nine fungicides, including 43% Fluopyram·Trifloxystrobin (SC), against the pathogen was determined using the mycelial growth rate method. Laboratory toxicity tests indicated that 43% Fluopyram‌·Trifloxystrobin (SC), 70% Thiophanate-methyl (WP), and 42.4% Pyraclostrobin·Fluopyram (SC) exhibited the strongest inhibitory effects against Corynespora. cassiicola, with EC50 values of 3.028 5 mg/L, 5.148 0 mg/L, and 8.787 9 mg/L, respectively. Moderately effective fungicides included 70% Mancozeb (WP), 75% Trifloxystrobin·Tebuconazole (WG), 32.5% Benzovindiflupyr·Azoxystrobin (SC), and 38% Pyraclostrobin·Boscalid (WG), with EC50 values of 21.844 3 mg/L, 31.841 8 mg/L, 32.080 1 mg/L, and 41.867 6 mg/L, respectively. The least effective agents were 40% Mefentrifluconazole·Pyraclostrobin (SC) and 75% Chlorothalonil (WP), with EC50 values of 192.466 9 mg/L and 1 341.062 0 mg/L, respectively. This study revealed that the new leaf spot disease on tobacco in Yongzhou was caused by C. cassiicola. C. cassiicola was identified as the causal agent of Corynespora leaf spot disease in tobacco. Strobilurin and benzimidazole fungicides showed superior inhibitory efficacy. The findings provide a scientific basis for the effective local control of tobacco Corynespora leaf spot disease.
Key words: tobacco; Corynespora leaf spot disease; Corynespora cassiicola; indoor virulence assay; fungicide
（Acta Laser Biology Sinica, 2026, 35(1): 053-061）