Emergence of <i>Ceratocystis eucalypticola</i> as a devastating wilt pathogen of <i>Eucalyptus</i> in China

Abstract A destructive canker and wilt disease has recently emerged as a significant threat to Eucalyptus plantations in southern China. Disease symptoms included bark cankers, wood discoloration, wilting, and large-scale tree mortality. A fungus exhibiting typical morpho-cultural characteristics of Ceratocystis species was frequently observed sporulating on affected trees and consistently isolated from symptomatic tissue. The aim of this study was to describe the disease and to identify its causal agent using morphological characters and multigene DNA phylogenies based on the β-tubulin 1 gene, translation elongation factor 1-alpha, and guanine nucleotide-binding protein subunit beta-like protein (MS204) regions. Pathogenicity was confirmed via controlled inoculation trials fulfilling Koch’s postulates. Phylogenetic analyses revealed that all the isolates were conspecific with Ceratocystis eucalypticola. To our knowledge, this represents the first documented outbreak of C. eucalypticola–induced wilt and canker disease in Eucalyptus plantations in China, highlighting an emerging phytosanitary challenge for the region’s forest industries.