越橘圆斑病病原菌鉴定及其生物学特性

Identification and Biological Characteristics of Round Leaf Spot on Blueberry Caused by Pestalotiopsis photiniae

首次对越橘圆斑病进行了病原鉴定、生物学特性及其室内药剂筛选研究。经形态特征鉴定和rDNA-ITS序列分析，确定Pp．jlnd09菌株为石楠拟盘多毛孢（Pestalotiopsis photiniae）。生物学特性测定结果显示，病原菌菌丝生长和产孢最佳培养基为PDA，较适碳氮源分别为葡萄糖和蛋白胨，适宜温度范围为10-30℃，最适培养温度为28℃。在pH值4．0～10．0条件下均能生长并产孢（最适pH值5．0），孢子萌发最适pH值6．0，最低相对湿度为80％，光暗交替有利于孢子的萌发，分生孢子的致死温度为45℃。室内毒力测定结果表明，250g·L^-1凯润EC、400g·L^-1福星EC、60％金万霉灵WP和50％翠贝GR4种杀菌剂对越橘圆斑病菌的抑菌效果显著高于其余药剂。

An experiment was conducted to study the pathogen identification, biological characteristics and indoor fungicide screening of the strain Pp. jlnd09 isolated from round leaf spot on blueberry. The pathogenic strain was identified as Pestlotiopsis photiniae according to its morphological characters as well as ribosomal DNA-ITS sequences. The biological characteristics of the strain showed that the optimum medium was potato dextrose agar（ PDA）, and dextrose and peptone could be used as the best carbon and nitrogen sources for the growth of P. photiniae, respectively. The temperature for myceliat growth and sporulation ranged between 10 and 30 degrees C and pH ranged from 4 to 10. The optimum temperature was 28 degrees C and the optimum pH was 5. The conidial germination was better at pH 6.0 or under illumination with alternating bright and dark. The eonidia failed to germinate if relative humidity was less than 80%, and the lethal temperatmc for conidia was 45 degrees C. The four fungicides, Cabrio（250 g · L^-1 ）, Mascot（400 g · L^-1 ）, Gold Wanmeiling（69% ） and Stroby（50% ）, had stronger inhibitory effects on P. photiniae compared with the others in the test.