目的 研究蝙蝠葛新病害-靶斑病的病原菌及其生物学特性和药剂敏感性。方法 组织分离法获得分离物并进行致病性测定;结合病原形态特征、培养特性及rDNA-ITS序列分析确定病菌分类地位;研究培养基种类、温度、pH值、碳氮源、光照对菌丝生长和菌核产生的影响;并用生长速率法测定病菌对14种杀菌剂的敏感性。结果 蝙蝠葛靶斑病由Streptobotrys caulophylli引起。菌丝生长最佳培养基为PDA培养基,菌核形成最佳培养基为PDA和PSA培养基;菌丝生长适宜温度为20～28 ℃,最适温度25 ℃;菌核产生适宜温度范围10～30 ℃,最适温度30 ℃;pH 4～9适宜菌丝生长,pH 5～11菌核产生数量最多;菌丝生长最佳碳源为蔗糖,氮源为L-谷氨酰胺;菌核生长最佳碳源为菊糖和蔗糖,最佳氮源为硝酸钠;全光照利于菌丝生长,全黑暗利于菌核形成。病菌对腐霉利、嘧菌环胺、异菌脲、咯菌腈、甲霜·锰锌、唑醚·代森联的敏感性较高,其有效中质量浓度(EC₅₀)<1.0 mg/L,EC₉₀<5.0 mg/L。结论 首次报道蝙蝠葛靶斑病的病原菌为S. caulophylli;确定了适合菌丝生长和菌核产生的培养基种类、温度、pH值、碳氮源以及光照条件;腐霉利、嘧菌环胺、异菌脲、咯菌晴、甲霜·锰锌、唑醚·代森联6种药剂可作为病害田间防治的备选药剂。

Objective To identify the pathogen of Menispermum dauricum target spot (a new plant disease in China) and study its biological characteristics and susceptibility to fungicides. Methods Tissue isolation method was used to obtain the isolates from diseased-leaf. The pathoginicity of the isolates was fulfilled according to Koch's postulate. The identification of the pathogen was carried out according to the morphological and cultural characteristics and rDNA-ITS sequence analysis. The effects of culture medium, temperature, pH value, carbon and nitrogen sources, and light on mycelium growth and sclerotia production of the pathogen were studied. The mycelium growth rate was used to test the susceptibility of pathogen for 14 fungicides. Results The M. dauricum target spot was caused by Streptobotrys caulophylli. The optimal medium for mycelium growth was PDA; PDA and PSA media were suitable for the sclerotium production. The optimal temperature ranges for mycelium growth and spore production were 20－28 ℃ and 10－30 ℃ and were suitable for sclerotium production. The suitable pH values for mycelium growth and sclerotium production were 4－9 and 5－11, respectively. Sucrose and L-glutamine were the optimal carbon and nitrogen sources for mycelium growth. Synanthrin and sucrose were the optimal carbon source and sodium nitrate was nitrogen source for sclerotium production. The total light could promote mycelium growth, while the darkness could promote sclerotium production. The pathogen was sensitive to procymidone, cyprodinil, iprodione, fludioxonil, metalaxyl·mancozeb, and pyraclostrobin·metiram with EC₅₀ < 1.0 mg/L and EC₉₀ < 5.0 mg/L. Conclusion It is the first report on M. dauricum target spot caused by S. caulophylli in China. The suitable conditions (culture medium, temperature, pH value, carbon and nitrogen sources, and light) for mycilium growth and sclerotium production are determined. The above six fungicides are screened as further field trial agents for disease control.

吉林省世行贷款农产品质量安全项目(2011-Z24)