马占相思苗木茎腐病的调查和病原鉴定

于2001年4～7月,对广西高峰林场总场中心苗圃和银岭分场新造林地的马占相思（Acacia mangium Willd）苗木茎腐病进行调查和病原鉴定。结果发现,茎腐病对1年生以内的马占相思扦插苗危害严重,3月份开始发病,4～6月份为盛发期,新造林地,炼苗苗床,扦插苗床的平均发病率分别为12.1%、18.3%、72.6%,平均病死率分别为10.5%、16.2%、53.5%,苗木幼嫩、有伤口、培养基质带菌,温暖潮湿等条件有利于该病的发生与曼延,病原菌为立枯丝核菌（Rhizoctonia solani Kuhn）和尖镰孢霉菌（Fusarium oxysporum Schiecht）,2种菌的致病力均很强。

Investigation and Pathogens Identification of Seedling Stem Rot of Acacia mangium Willd

The seedling stem rot disease of Acacia mangim Willd was investigated in the central nursery and the new afforestation field of Yinling Forestry Farm from April to July 2001.This disease did a serious damage to the annual cutting seedlings,and appeared in March and prevailed from April to June, The average morbidities in the new afforestation field, seedbed for training seedlings and cutting seedbed were 12.1%?18.3%?72.6%,respectively, with corresponding mortalities averaging 10.5%?16.2%?53.5%. The tender and wound seedlings,the substrata infected with pathogens and the warm and wet climate are the favor conditions for the diseases happening and spreading.The pathogens were identified to be Rhizoctonia solani Kuhn and Fusarium oxysporum Schiecht.The pathogenicity test showed that these pathogens had strong pathogenicity to the seedlings of A.mangium Willd.