大叶黄杨灰斑病病原菌鉴定、生物学特性及五种杀菌剂对其抑制作用

Identification, biological characteristics and inhibitory effect of five fungicides on the pathogen causing gray leaf spot of Euonymus japonicus

为明确大叶黄杨灰斑病病原菌种类、生物学特性和对杀菌剂的敏感性,采用组织分离法获得大叶黄杨灰斑病病原菌,利用形态特征和分子生物学对其进行鉴定,系统研究该病原菌的生物学特性,并用生长速率法测定了80%代森锰锌、80%代森锌、70%百菌清、50%多菌灵和430 g/L戊唑醇5种杀菌剂对该病原菌生长的抑制效果。致病性测定结果表明,从感病植株分离所得菌株能在大叶黄杨叶片上成功定殖并扩展,且从发病部位分离得到的菌株与原接种菌株相同。通过病原菌的宏观形态、显微结构和ITS序列分析,确定该病原菌为斑污拟盘多毛孢Pestalotiopsis maculans;当葡萄糖为碳源、蛋白胨为氮源时,菌丝日生长速度最快,分别为4.08、4.90 mm/d;当温度为21~28℃、pH为7时,菌丝日生长速度最快,分别为5.07~5.16 mm/d和5.21 mm/d;50%多菌灵对该菌的抑制效果最好,抑制中浓度EC50最小,为0.06 μg/mL。

In order to identify the species, biological characteristics and sensitivity to fungicides of the pathogen causing the gray leaf mold spot of Euonymus japonicus, the pathogen was obtained by tissue isolation from the infected E. japonicus leaves;it was identified according to its morphological and molecular characters, and its biological characteristics were systematically studied;moreover, the inhibitory effect of five fungicides (80% tiezene, 80% mancozeb, 70% chlorothalonil, 50% carbendazim and 430 g/L tebuconazole) on the pathogen was tested by using growth rate method. Based on pathogenicity test, the mycelium was successfully colonized and expanded on E. japonicus leaves, and the same species strain was isolated from the discolored part. According to the pathogen's morphology, microstructure and ITS sequence, the pathogen was identified as Pestalotiopsis maculans. When the carbon source was glucose and the nitrogen source was peptone, the hyphal growth rates were fastest (4.08, 4.90 mm/d, respectively). When temperature ranged from 21℃ to 28℃ and pH was 7, the hyphal growth rates were fastest (5.07-5.16 and 5.21 mm/d, respectively). 50% carbendazimwettable powder had the best inhibition effect on P. maculans, with a smallest EC50 value of 0.06 μg/mL.