Diversity of Botryosphaeriaceae Species Associated with Chinese Hickory Tree () Trunk Cankers.

Tree trunk cankers represent serious fungal diseases that pose significant threats to Chinese hickory trees (). To characterize the pathogen diversity associated with this disease, tissues were collected between 2016 and 2018 from the primary Chinese hickory plantation regions. A total of 97 cultures were isolated from trees in six towns (Longgang, Qingliangfeng, Changhua, Tuankou, Taiyang Town, and Lin'an urban area) within the Linan district, where 60% of Chinese hickory tree yields originate. The isolated cultures caused cankers on Chinese hickory tree branches, but infections did not occur on fruits or leaves under tested conditions. Combined morphological observations and phylogenetic analysis of multiple genes (, β-, and ) indicated that five species were recovered, including 89 isolates of , 4 isolates of , 1 isolate of , 1 isolate of , and two isolates of . . was the most prevalent, and this is the first report of . , . , and . infections in Chinese hickory trees. We investigated the mycelial growth, spore germination, and pathogenicity of these species at different temperatures. . grew the fastest and . grew the slowest on potato dextrose agar. The optimum temperature of spore germination for all species was 30°C. . was the most virulent species, followed by . and . , then . , and finally . . These new insights into fungal pathogen diversity provide critical new information to understand and manage tree trunk cankers of Chinese hickory.