Diseases caused by species of Calonectria (Ca.) represent a serious threat to the growth and sustainability
of Eucalyptus plantations in China. Symptoms caused by these fungi mainly include leaf blight on trees in plantations
and rotting of stems and leaves in nurseries. Extensive surveys have recently been conducted where Calonectria
species were collected in Eucalyptus plantations and nurseries in the FuJian, GuangDong, GuangXi, and YunNan
Provinces of South China. Additional isolates were baited from soil samples in the Hong Kong Region. The aim of this
study was to identify the 115 Calonectria isolates obtained using comparisons of DNA sequence data for the β-tubulin
(tub2), calmodulin (cmdA), histone H3 (his3) and partial translation elongation factor-1α (tef1) gene regions as well as
their morphological features. Seven known species were identified, including Calonectria arbusta, Ca. asiatica, Ca.
chinensis, Ca. eucalypti, Ca. hongkongensis, Ca. mossambicensis and Ca. pentaseptata. In addition, six novel taxa
were collected and are described here as Ca. aciculata, Ca. honghensis, Ca. lantauensis, Ca. pseudoturangicola, Ca.
pseudoyunnanensis, and Ca. yunnanensis spp. nov. Overall, the results reflect a high diversity of Calonectria species