RESUMEN
In order to scientifically prevent and control Dendrobium catenatum southern blight disease,the main factors related to this disease occurrence,the pathogen( Sclerotium delphinii),environmental factors( temperature and humidity) and D. catenatum germplasms,were investigated. The results showed that reaching 25-30 ℃ temperature and over 95% humidity simultaneously should be the main conditions for the occurrence and prevalence of D. catenatum southern blight disease. Moreover,the S. delphinii-infected plants and their contaminated substrates were the disease spreading sources. Therefore,removing the infected plants,dealing with the contaminated substrates,keeping air ventilation,and reducing air humidity are the effective ways to prevent and control the occurrence and prevalence of D. catenatum southern blight disease. The research also indicated that D. catenatum has different resistances to the southern blight disease depending on germplasm. The present study lays important foundations for the breeding of D. catenatum diseaseresistant varieties and the further analysis of the infection and resistance mechanisms underlying southern blight disease.