Pathogenicity and Biological Characteristics of <i>Botryosphaeria dothidea</i> Causing Branch Blight of <i>Salix babylonica</i>

ABSTRACT Salix babylonica L. is a popular ornamental and ecological tree species. In this study, the results of pathogenicity tests showed that the Botryosphaeria dothidea isolates JXL1‐3, JXL1‐5, JXL1‐11, L1‐3, L2‐2, NFS1, NFS2, NFS5 and WLS1 were pathogens causing branch blight on S. babylonica . Meanwhile, the B. dothidea isolates JXL1‐11, L1‐3, NFS1 and WLS1 were found to be pathogenic to two other willows, S . chaenomeloides and S. suchowensis . The biological characteristics of B . dothidea isolates JXL1‐11, L1‐3, NFS1 and WLS1 were investigated under different conditions, including culture media, pH, temperatures, carbon/nitrogen sources and light. It was found that potato dextrose agar (PDA) medium was the most optimal medium for the B . dothidea isolates JXL1‐11, L1‐3, NFS1 and WLS1 mycelial growth, the suitable pH was 4, and the optimal temperatures were 25°C–30°C. The optimal carbon sources were glucose and sucrose, and the optimal nitrogen sources were ammonium sulfate and peptone. The optimal light condition for inducing sporulation was dark + ultraviolet light. This study provides a fundamental basis for the prevention and control the branch blight on willows and further studies.