烟草靶斑病病原鉴定及室内药剂毒力测定

Identification of the Pathogens of Target Spot Disease and Screening of Fungicides in Tobacco

为明确烟草靶斑病病原菌的分类地位并筛选出防控药剂,本研究对贵州省开阳县烟草靶斑病病叶进行分离纯化,通过致病性测定、形态学观察、生物学特性以及rDNA-ITS分析鉴定,确定了烟草靶斑病病原菌为立枯丝核菌Rhizoctoniz solani。研究发现该病原菌最适生长温度范围为25~30℃,最适pH值为6,蔗糖、蛋白胨分别是较好的碳、氮源。以28%井冈霉素为对照药剂,供试7种杀菌剂均对该病原菌有抑制效果,其中0.03%四霉素抑菌活性最高,EC 50为0.04 mg/L,其次是80%戊唑醇,EC 50为0.44 mg/L。试验结果为烟区有效控制烟草靶斑病的发生蔓延提供依据。

In order to clarify the taxonomic status of the pathogenic fungi of tobacco target spot disease and screen out the control agents,this study isolated and purified the diseased leaves of tobacco target spot in Kaiyang County,Guizhou Province.Through pathogenicity determination,morphological observation,biological characteristics and rDNA-ITS analysis and identification,the pathogen of tobacco target spot was identified as Rhizoma solani.It was found that the optimum growth temperature range of the pathogen was 25-30℃,the pH value was 6,and sucrose and peptone were the better carbon and nitrogen sources.Taking 28%Jinggangmycin as the control agent,all of 7 fungicides had inhibitory effect on the pathogen,among which 0.03%tetramycin had the highest antifungal activity with EC 50 of 0.04 mg/L,followed by 80%tebuconazole,EC 50 was 0.44 mg/L.The above test results can provide a basis for effective control of the occurrence and spread of tobacco target spot disease in tobacco areas.