布氏白僵菌对大栗鳃金龟的致死能力测试

Fatality Rate and Pathogenic Process Observation of Melolontha hippocastani mongolica Infection by Beauveria brongniartii

从野外病亡的大栗鳃金龟Melolontha hippocastani mongolica体内分离出了疑似病原物,经鉴定为布氏白僵菌Beauveria brongniartii。为了明确布氏白僵菌对大栗鳃金龟不同虫龄幼虫的致死能力,实验采用了拌土法和直接喷洒法将布氏白僵菌孢子接种到不同虫龄的大栗鳃金龟幼虫,并定期观察期死亡率。结果表明:布氏白僵菌对大栗鳃金龟1龄和2龄幼虫的致死率与对照具有显著差异,且具有较强致死能力,35 d时最高达到了93.3% ±0.1745和66.7% ±0.1434;大栗鳃金龟3龄幼虫和成虫的致死率最高仅为25.1% ±0.0598和2.22% ±0.0148,与对照和低龄幼虫均有显著性差异;并且土壤温度和致死率呈高度正相关,12℃~20℃范围内,观测所得的决定系数(R2)分别为0.97267;0.99725;0.98256;0.96223;0.92550。因此,布氏白僵菌在生产上有作为生物杀虫剂的巨大潜力,可用于鳃金龟低龄幼虫的生物防治,具体的方式方法还有待于进一步深入研究。

To reveal the toxicity of the Beauveria brongniartii to the soil pest Melolontha hippocastani mongol-ica which seriously threats to the production of the fritillaries, though the vaccination experiment of Beauveria brongniartii to the Melolontha hippocastani mongolica on their different stage, including one to three larvae stage and the adults, significantly different mortality rates were shown in differ-ent stages. The analysis indicated that the Beauveria brongniartii has significant cytotoxicity to the 1rst and 2nd larvae of Melolontha hippocastani mongolica which fatality rate up to 93.3% ±0.1745 and 66.7% ±0.1434. While it’s invalid to the 3rd in star and adults, the corresponding value is 25.1% ±0.0598 and 2.77% ±0.0148. Data shows that there was a significant positive correlation between mortality and temperature in the 2nd larva under 12 to 20 Centigrade. So, the conclusion is that the Beauveria brongniartii can be applied in the bio-control of the Melolontha hippocastani mongolica in their younger lava stage as a possibly potential bio-pesticide, especially in higher temperature.