Wide Distribution of and Associated with Diseased Leaves in Plantations in Southern China.

Species of and represent over 40% of the fungi identified on eucalypt leaves worldwide. These include some important pathogens that mainly cause leaf blight and spot, and result in increasingly negative impacts on global commercial eucalypt industries. plantations are commonly cultivated in southern China for solid wood and pulp products. However, the species diversity and geographic distribution of and , associated with diseased plantation leaves in China, have not been clarified. In this study, we conducted the first systematic surveys and sample collections of - and -like fungi from diseased plantation leaves in southern China. In total, 558 isolates were obtained from 59 sampled sites in five provinces. One isolate was isolated from each tree. According to the disease symptoms, conidia morphological characteristics, and DNA sequence comparisons of ITS, and gene regions. The 558 isolates were identified as (312 isolates; 55.9%) and (246 isolates, 44.1%). Both species were widely distributed in the sampled regions in southern China. The genotypes of and were determined based on ITS, , and sequences. The results showed that multiple genotypes of each species of and exist in China. Additionally, isolates with multiple genotypes were obtained in all five sampled provinces. These results suggest that both and are not clonal. This study proved that both and are dominant species and widely distributed on diseased leaves in southern China. The wide geographic distribution and potential high genetic diversity pose challenges for the disease management of leaf blight and leaf spot in China.