河北大花蕙兰疫病病原鉴定及其生物学特性分析

为了明确大花蕙兰疫病的发生机制,对河北地区引起大花蕙兰疫病的病原菌进行分离、纯化、鉴定和接种试验,并对大花蕙兰疫病的病原菌进行生物学特性分析。结果表明,河北大花蕙兰疫病的病原菌为掘氏疫霉(Phytophthora drechsleri),有伤接种3 d后即可以产生典型疫病症状。病原菌的适应能力较强,在24~32℃和pH值4.0~10.0条件下均能正常生长,其最适生长温度为28℃,最适pH值为7.0。在V8培养基、查氏培养基和CA培养基上均生长良好,但在PDA培养基上生长较差。在无菌水中连续光照培养2 d即可诱导产生大量孢子囊和孢囊孢子。孢囊孢子保湿12.0 h萌芽率即可达90.0%以上,适宜萌芽温度为20~40℃,最适萌芽温度为30℃,适宜萌芽pH值为4.0~9.0,最适pH值为7.0。以上研究表明,河北地区大花蕙兰疫病病原菌具有较强的致病力和环境适应能力。

Pathogen Identification and Biological Characteristics of Cymbidium hybridium Blight in Hebei Province

In order to clarify the occurrence mechanism of Cymbidium hybridium blight,the pathogen was isolated,purified,identified,and re-inoculated in Hebei province.The biological characteristics of the pathogen were analyzed at the same time.The results showed that the pathogen of Cymbidium hybridium blight in Hebei province was identified as Phytophthora drechsleri,which could produce typic blight symptom after 3 days of wound inoculation.The pathogen was strongly adaptive to environment and could grow well at 24-32 ℃ and pH 4.0-10.0.The optimal growth temperature and pH value of the pathogen was 28 ℃ and 7.0 respectively.The pathogen could grow well in the V8 medium,Chavez medium and CA medium,but poor in PDA medium.A large number of sporangia and sporangiospores could be easily induced after 2 days of continuous illumination in autoclaved water.The germination rate of sporangiospores was above 90.0％ after 12.0 h of moisture culture.The sporangiospore could germinate very well at 20-40 ℃ and pH 4.0-9.0.The optimal temperature and pH value of sporangiospore germination were 30 ℃ and 7.0 respectively.The above results indicated that the pathogen of Cymbidium hybridium blight in Hebei province possessed strong pathogenicity and environmental adaptivity.