顶果木灰霉病病原鉴定

【目的】对顶果木灰霉病病原菌进行鉴定,以明确其分类地位,为顶果木灰霉病的防控提供参考依据。【方法】从广西南宁市良凤江国家森林公园苗圃基地采集顶果木灰霉病病害标本,对病害进行症状描述、组织分离和致病性测定,观察致病菌的形态学特征并进行r DNA-ITS序列分析。【结果】分离获得顶果木灰霉病致病菌代表菌株DGM5-6。DGM5-6菌株在PDA上长势良好,毛绒状菌落初期呈淡黄白色,后期逐渐变为灰白色;气生菌丝呈放射状生长,开始为白色,生长后期为灰色;病菌分生孢子梗单生,灰色至褐色,分枝,顶端膨大成球形,其上有多个小梗,梗上聚生卵形、圆形或椭圆形的分生孢子;分生孢子呈浅灰色至无色,单胞,大小为10.0-12.5μm×7.5-10.0μm。DGM5-6菌株ITS基因扩增片段长度为535 bp,其r DNA-ITS序列与Gen Bank中灰葡萄孢（Botrytis cinerea Pers.ex Fr）序列的同源性达99%。【结论】引起广西顶果木灰霉病的病原为灰葡萄孢（Botrytis cinerea Pers.ex Fr）,该病原菌寄主范围广,应结合苗圃清园、圃地治理、合理密植、生物防治和化学防治等进行防控。

Identification of Acrocarpus fraxinifolius grey mould pathogen

【Objective】The pathogen of Acrocarpus fraxinifolius grey mould was identified in order to ascertain taxonomic status of the pathogen and provide references for the prevention and control of A. fraxinifolius grey mould.【Method 】A. fraxinifolius grey mould samples were collected from the nursery base in Nanning Liangfengjiang Forest park and pathogenicity was confirmed by the disease symptom. After that the isolates were identified via their morphological features and r DNA- ITS sequence analysis. 【Result 】The representative strain DGM5-6 was isolated from A.fraxinifolius grey mould samples. It grew well on the Potato Dextrose Agar（PDA） medium. Villous colony was yellowish white in the beginning and finally became offwhite in a gradual way. Aerial mycelium appeared radial growth and changed from white to gray. Conidiophore of pathogen was born singly, gray to brown, branched, and the top of the sporophore swelled into a ball with a lot of sterigmas on it. The top of the sterigmas was ovoid, round or oval conidia.The conidia were pale gray to colorless, single cell, and the size of the conidia was 10.0-12.5 μm ×7.5-10.0 μm.The length of ITS gene amplification fragment of DGM5-6 strain was 535 bp. The homologous of this sequence was compared in Gen Bank and the result showed 99% homology with Botrytis cinerea Pers.ex Fr. 【Conclusion 】The pathogen is identified as Botrytis cinerea, which has a wide range of host. The prevention and control should be combined with cleaning up the nursery, soil management, rational close planting, biological control and chemical control.