白僵菌Bb0812菌株生物学研究及其对美国白蛾的致病性

对采自美国白蛾僵虫的虫生真菌Bb08 12菌株进行了生物学研究及致病性测定。根据该菌株的形态特征将其初步鉴定为球孢白僵菌（Beauveria bassiana）。室内测定结果表明：该菌株在26 ℃恒温、高湿度下对1龄中期美国白蛾幼虫具有较强的致病力。107 孢子/mL剂量饲毒处理幼虫72～120 h，幼虫死亡率可达25.47%～79.32%，120 h的LC50 为1.169×106孢子/mL。该菌株在不同培养基上菌落形态差异明显。沙氏培养基上产孢量最高，10 d产孢量可达到5.59×108孢子/cm2，极显著高于PSA、查彼培养基和5%麸皮 蔗糖固体培养基上的产孢量。24 h光照和24 h黑暗两处理间的菌落生长量差异不明显，而在培养的最初48 h，24 h黑暗处理可显著促进分生孢子萌发。

Biological characteristics and pathogenicity of Beauveria bassiana Bb08 12 to Hyphantria cunea larvae

Biological characteristics and pathogenicity of the entomogenous fungi Bb08 12, isolated from Hyphantria cunea larvae, to H. cunea were investigated in this study. The strain Bb08 12 was primarily identified as Beauveria bassiana according to its morphology. The results showed that the strain Bb08 12 had stronger pathogenicity to H. cunea at higher humidity and constant temperature (26 ℃) in the laboratory. When H. cunea larvae were fed with leaves containing 1×107 spores/mL, the 25.47%-79.32% larvae were killed after 72-120 h. The LC50  was 1.169×106 spores/mL at 120 h.The colony forms of B. bassiana Bb08 12 were remarkably different on different culture media. The number of conidia on SDAY culture medium was the highest, reaching to 5.59×108 spores/cm2 in 10 days, which was significantly greater than that on PSA, Czapek and 5% bran sucrose culture media. The growth rates of colonies were not remarkably different between 24 h light and 24 h darkness. Conidia germination was significantly improved in 24 h darkness in the initial 48 h.