桉树溃疡病病原菌的鉴定

Identification of the pathogen causing canker in eucalyptus

桉树（Eucalyptus ssp．）是世界人工造林三大速生树种（桉树、杨树与松树）之一，也是我国南方营造速生丰产林的主要造林树种。目前，全国桉树人工林面积已超过200万hm2。随着桉树人工纯林的面积扩大，桉树病害也日趋加重，严重影响和制约桉树产业的发展。2008年至今，在云南省石林县和红河州桉树种植区发生一种病害，主要为害嫩枝、枝条和主干，发病初期，感病枝条和主干上产生红褐色圆或椭圆形坏死斑，以后逐渐扩大成椭圆或不规则溃疡斑，病变扩展到木质部后，常造成枝条生长畸形，易引起刮风断裂。

The identification of the pathogens isolated from the canker of eucalyptus （Eucalyptus grandis） were carded out. Seventeen diseased eucalyptus samples were observed in Shilin and Honghe in Yunnan Province （ south-western China）. Seventeen isolates of possible pathogenic fungi were isolated from trunks and branches of infected eucalyptus plants. Bases on the pathogenicity experiment, the results showed that YNE1- YNE17 were the pathogens of eucalyptus （E. grandis ） canker disease. The morphological identification showed that YNE1-YNE17 was identified as Botryosphaeria dothidea. By analysis of the rDNA internal tran- scribed spacer region （ ITS1-5.8S-ITS2 ）. BLAST searches at GenBank showed a high identity with reference sequences （99% - 100% ）. Representative sequences of both regions were deposited to GenBank （ Accession No. FJ517657, FJ517658 ）. Morphological and molecular identification confirmed this species as B. do- thidea. B. dothidea was first reported as the pathogen of eucalyptus canker and shoot blight disease in China.