非洲凤仙茎基腐病病原学及药剂敏感性1）

对非洲凤仙（Impatiens wallerana Hook．f．）茎基腐病的症状进行了描述，结合病原形态特征、培养特性及rDNA－ITS序列分析结果，确定该病害由Rhizoctonia solani Kühn AG4－HG－Ⅰ融合群引起。病菌的生物学特性研究表明：菌丝较适生长温度为25～30℃；菌丝生长较佳的培养基为OA和PSA，较佳的碳源为D－（＋）麦芽糖、α－乳糖和可溶性淀粉，较佳的氮源为硝酸钾和硝酸钠；pH＝7时菌丝生长最好；光照条件对菌丝生长无影响；菌丝致死条件为51℃、10 min。采用生长速率法测定了病菌对30种杀菌剂的敏感性，结果表明，病菌对≥300亿个· g－1内生芽孢杆菌WP、1000亿个· g－1枯草芽孢杆菌WP、25％肟菌·50％戊唑醇WG、40％氟硅唑EC敏感性较高，对其EC50＜1．0 mg· L－1，可以作为田间防治非洲凤仙茎基腐病的首选杀菌剂。

Pathogen Identification and Fungicides Susceptibilityo n Impatiens walleriana Root and Stem Rot

We described the symptoms of Impatiens walleriana root and stem rot disease .Based on the morphology , cultural characteristics of the isolates and ITS sequence , we identified the pathogen as Rhizoctonia solani Kühn AG4-HG-I.The results of the biological characteristics of the pathogen showed that the suitable temperature for mycelial growth was 25℃-30℃.The optimal media for mycelial growth were OA and PSA .D-(+) Maltobiose,α-lactose,soluble starch, potassium nitrate and sodium nitrate were optimal for mycelial growth .The pH of 7 was suitable for mycelial growth .Light had no effect on mycelial growth .The lethal temperature of mycelial was 51℃for 10 min.The susceptibility of the pathogen to 30 fungicides was detected by mycelial growth rate method .The pathogen was more sensitive to Endophytic Bacillus WP , Ba-cillus Subtilis WP, Trifloxystrobin· Tebuconazole 25%· 50%WG, Flusilazole 40%EC, EC50<1.0 mg/L.