Identification and Pathogenicity of Pestalotioid Species on Alpinia oxyphylla in Hainan Province, China.

Alpinia oxyphylla is a traditional Chinese medicinal plant with a medicinal history of more than 1700 years. Ring leaf blight (RLB) disease, caused by pestalotioid species, is an important disease of A. oxyphylla , seriously affecting the yield and quality of its fruits. The causal agent of RLB disease has not been systematically identified or characterized yet. In this study, thirty-six pestalotioid strains were isolated from the leaves and stems of A. oxyphylla that was collected from six cities of Hainan province, China. Based on the multi-locus phylogeny ( ITS , tef-1α and tub2 ) and morphological characteristic analyses, seventeen species belonging to three genera ( Neopestalotiopsis , Pestalotiopsis and Pseudopestalotiopsis ) were identified, and six new species ( N. baotingensis , N. oblatespora , N. olivaceous , N. oxyphylla , N. wuzhishanensis and N. yongxunensis ) were described. Pathogenicity tests revealed that strains of Neopestalotiopsis species caused more severe ring leaf blight on A. oxyphylla than strains of Pestalotiopsis and Pseudopestalotiopsis under wounded inoculation conditions.