中文摘要：

【目的】确定海南省近年发生的新病害——龙眼红粉病病原菌种类,为科学防治提供理论依据。【方法】采集海南省龙眼主产区龙眼红粉病病果样本,通过对病原菌形态观察、致病性测定,以及病原菌的rDNA 28S和rDNA ITS序列分析进行病原鉴定。【结果】经分离纯化获得病原菌,培养后回接健康龙眼果实,出现的病害症状与田间发病症状一致,再次分离得到同样病菌,确定其为致病菌;对病原菌进行传统形态学观察,病原菌分生孢子的形态为粉红单端孢菌属真菌,将待测菌株rDNA-ITS和rDNA-28S序列与GenBank中相关菌株的序列进行比较,发现其致病菌与Trichothecium roseum的相似性达到99%。【结论】确定海南省龙眼主产区新病害龙眼红粉病的病原菌为粉红单端孢菌Trichothecium roseum。

英文摘要：

[Objective] Longan （Dimocarpus longana Lour.） is one type of evergreen tree, which is widely grown in the subtropical zone of South China. Along with the＇ development of the longan industry, the dis- eases associated with this tree increased gradually. A new disease was discovered in Hainan, which oc- curs in the endangered growth stage of the longan fruit. According to its symptoms, it was named the ＂pink disease.＂ This disease has been the most important factor influencing the quality and production of longan fruit. The objective of this study is to identify the pathogen and supply a theory as the basis for scientific control of this disease in the future. [ Methods ] Investigated the prevalent situation of the longan new dis- ease in the field for three years in succession from 2013 to 2015. The longan fruit which had the pink dis- ease were collected from the main producing areas in Hainan province. We identified the pathogen on the unhealthy longan through morphology and recorded the spore identified through morphology. One-centi- meter disks of the diseased longan fruit were collected from the field and were cut and surface-sterilized with 75% ethanol and 1%0 HgC12. The disks were placed on a potato dextrose agar （PDA） medium in order to establish cultures at a temperature of 26-28 ℃ for 7 days. Each pure culture was obtained by subcul- turing hyphal tips onto anther fresh PDA plates, and separating the pured pathogen single spores. To con-firm the Trichothecium roseum isolates as the causative pathogen, healthy longan fruit （five bunches of Ion- gala fruit） from longan trees were sprayed with a conidial suspension （approximately 1.0×10^5 CFU·mL^-1） of the isolates and incubated at 20 ℃ and 100% relative humidity with plastic and incurring natural cycles of light and darkness. Approximately 1 mL of conidial suspension solution was used for each group of Ion-gan fruit. The groups of longan fi＇uit were sprayed daily with sterile double-distilled water. As negaUve controls, five g