【作者】 王国昌；

【导师】 谢映平；

【作者基本信息】 山西农业大学 ， 森林保护学， 2003， 硕士

【摘要】 松毛虫类（Dendrolimus）是我国松林的重大害虫类群，以往采用白僵菌（Beauveria）防治害虫多在南方，由于北方气候干旱少雨且低温期长，使它的防治应用受到限制。本次实验从2001年10月份开始，到2003年3月份，在灵丘县油松林内采集到油松毛虫（Dendrolimus tabulaeformis Tsai et Liu）越冬幼虫的病死僵尸，经实验室分离、培养、鉴定，确认其致死病原物为半知菌亚门（Deuteromycotina）丝孢纲（Hyphomycetes）丝孢目（Hyphomycetales）白僵菌属（Beauveria）的球孢白僵菌（Beauveria bassiana），并对它的生物学特性，菌落的生长速度，菌株的产孢量，分生孢子的萌发率，以及该菌株对油松毛虫幼虫的致病力进行了研究，其结果如下： 1．调查发现，在连年发生油松松毛虫危害的灵丘县下关林区能够采集到数量较多的被白僵菌侵染致死的油松毛虫僵尸，在林分干燥的环境中油松毛虫自然染病率很低。 2．在实验室对分离提纯后的白僵菌进行了一系列的生物测定。描述了该菌种的形态特征。掌握了该菌株的生长速度在温度为26±1℃的条件下最快，平均为4.12mm／d，在温度为7±1℃的条件下最慢，为1.99mm／d，在15±1℃的条件下菌株的生长速度介于二者之间，为3.77mm／d。菌株的产孢量在温度为26±1℃下最高，为4.49×10⁸分生孢子／cm²，温度为15±1℃时，产孢量为4.13×10⁸分生孢子／cm²，在7±1℃时，为2.44×10⁷分生孢子／cm²。测得孢子的萌发率为100％。 3．在不同的温度和湿度条件下，用5种浓度梯度的分生孢子悬浮液分别感染1～4龄的油松毛虫幼虫。结果表明，温度在25℃、空气相对湿度为（95±5）％时，各龄幼虫的死亡率最高、LT₅₀最低。经过对比，得出虫龄的易感性从高到低依次为1龄＞2龄＞3龄＞4龄。采用5种浓度的菌液做幼虫染病试验，其中以5×10⁸和1×10⁸分生孢子／ml两种浓度的致死率最高，显著高于其余3种浓度，但这两种浓度之间的差异不显著。综合比较，浓度为1×10⁸分生孢子／ml的悬浮液，致病力强，成本较低，可在生产中参考应用。更多还原

【Abstract】 Pine caterpillar, Dendrolimus (Lepidoptera : Lasiocampidae) is a kind of great injurious pest to pine forest in China. Beauveria as the disease-producing germ is often used to control these pests in south part of China. But it is limited in north part of China, because of the climatic characteristics such as less rain, dry and lower temperature. This thesis is to study the pathogens of pine caterpillar in north China The disease-producing germ was obtained from the larval illness corpse of Dendrolimus tabulaeformis Tsai et Liu which was collected from the pine forest of Lingqiu County, Shanxi Province, during 2001-2003. The results showed as following:1. Through isolation, culture and observation, the disease-producing germ was identified as Beauveria bassiana, belongs to the genus, Beauveria in the order, Hyphomycetes, the class of Hyphomyceres and the subphylum Deuteromycotina. Its morphological characteristics were described.2. Some biological characteristics were known on the entomogenous. Its growth rates were 4.12mm/d, 3.77mm/d and 1.99mm/d when the cultural temperatures were respectively set at 26 ± 1℃, 15 ± 1℃ and 7 ±1℃. The bourgeon rate of its spores was 100%.3. The germ solution in five different concentrations was tested to infect the larvae of Dendrolimus tabulaeformis in the stages of 1 - 4 instar. The result showed that at 25℃ and the relative humidity of (95± 5 ) %, the mortalities of the larvae appear the supreme and theLT50 is the lowest. The two concentrations 5× 10 and 1 × 10 spores/ml caused the most mortality of the larvae in the 5 concentrations tested. Therefore, the concentration of 1 × 108 spores/ml was recommended for controlling the pest in practice.更多还原