昆虫学报 ›› 2020, Vol. 63 ›› Issue (7): 835-842.doi: 10.16380/j.kcxb.2020.07.007

• 研究论文 • 上一篇    下一篇

孢悬液浓度和宿主体型大小对球孢白僵菌对松墨天牛幼虫的致病力的影响

郭涵1,2, 刘柱东1, 孙江华1,3,*   

  1. (1. 中国科学院动物研究所, 农业虫害鼠害综合治理研究国家重点实验室, 北京 100101; 2. 中国科学院大学, 北京 100049; 3. 中国科学院生物互作卓越创新中心, 北京 100049)
  • 出版日期:2020-07-20 发布日期:2020-07-29

Effects of spore suspension concentration and host body size on the pathogenicity of Beauveria bassiana against Monochamus alternatus (Coleoptera: Cerambycidae) larvae

GUO Han1,2, LIU Zhu-Dong1, SUN Jiang-Hua1,3,*   

  1.  (1. State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Science, Beijing 100101, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China; 3. CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China)
  • Online:2020-07-20 Published:2020-07-29

摘要: 【目的】球孢白僵菌Beauveria bassiana是一种被广泛用于害虫生物防治的生防菌。本研究探讨了孢悬液浓度和宿主体型大小对球孢白僵菌对松墨天牛Monochamus alternatus 幼虫的致病力的影响,旨在为松墨天牛的生物防治提供科学基础。【方法】分别用0.5% 吐温-80(CK)以及1×105, 1×106, 1×107, 1×108和1×109孢子/mL的球孢白僵菌孢悬液接种松墨天牛4龄幼虫,统计接种后15 d内幼虫死亡率和染菌率。同时用最佳浓度(1×109孢子/mL)的球孢白僵菌孢悬液接种体型大小分别为100~150, 200~220, 300~320, 400~420, 500~520和600~650 mg/头的松墨天牛幼虫,测定接种后20 d内幼虫的死亡率和染菌率。【结果】接种1×105~1×109孢子/mL的球孢白僵菌后,松墨天牛4龄幼虫起初活动自如,后在头部出现烧灼状伤并且体色逐渐变红,最后周身长满菌丝。不同浓度下,随球孢白僵菌孢子浓度升高,松墨天牛4龄幼虫校正死亡率和校正染菌率增加。接种1×106~1×109孢子/mL球孢白僵菌孢悬液15 d的松墨天牛4龄幼虫累计校正死亡率均可达到100%,1×107, 1×108和1×109孢子/mL浓度下,松墨天牛达到100%校正死亡率所需时间最少。接种0 (CK), 1×105, 1×106, 1×107, 1×108和1×109孢子/mL球孢白僵菌孢悬液的松墨天牛4龄幼虫校正染菌率在第15天分别为0, 20.00%, 86.67%, 90.00%, 96.67%和100.00%,表现为白僵菌孢子浓度越高,染菌率越高。1×109孢子/mL的接种浓度下,松墨天牛幼虫个体越大,天牛幼虫死亡率和染菌率越高。表现在第20天时,体型大小为100~150, 200~220, 300~320, 400~420, 500~520和600~650 mg/头的幼虫的死亡率分别为76.67%, 76.67%, 66.67%, 93.33%, 100.00%和100.00%,染菌率分别为60.00%, 63.33%, 60.00%, 86.67%, 96.67%和100.00%。【结论】球孢白僵菌悬浮液浓度对松墨天牛幼虫的死亡和侵染有显著影响,表现为随孢子浓度的增加而增加;同时,松墨天牛幼虫个体越大,死亡率和染菌率越高。研究结果对开展利用球孢白僵菌防治松墨天牛具重要借鉴和指导意义。

关键词: 球孢白僵菌, 松墨天牛, 孢悬液, 体型大小, 致病力, 染菌率, 生物防治

Abstract: 【Aim】 Beauveria bassiana is widely used in the biological control of insect pests. This study aims to investigate the effects of spore suspension concentration and host body size on the pathogenicity of B. bassiana against the Japanese pine sawyer, Monochamus alternatus, so as to provide basic information for practical biological control of M. alternatus using fungi B. bassiana. 【Methods】 After the 4th instar larvae of M. alternatus were inoculated with 0.5% Tween-80 (CK) and different concentrations (1×105, 1×106, 1×107, 1×108 and 1×109 conidia/mL) of B. bassiana spore suspension, respectively, the larval mortality and infection rate within 15 d post inoculation were assayed. Furthermore, after M. alternatus larvae in different body size (100-150, 200-220, 300-320, 400-420, 500-520 and 600-650 mg/individual) were inoculated with the optimal concentration (1×109 conidia/mL) of B. bassiana spore suspension, the larval mortality and infection rate within 20 d post inoculation were determined. 【Results】 After inoculation with 1×105-1×109 conidia/mL B. bassiana spore suspension, the 4th instar larvae of M. alternatus moved freely at the beginning, then they showed burned symptom on the head and their body color gradually turned red. Finally, the whole body was covered with hyphae. With the increase of spore concentration of B. bassiana, the corrected mortality and infection rate of the larvae increased significantly. When the 4th instar larvae were exposed to 1×106-1×109 conidia/mL B. bassiana spore suspension for 15 d, their accumulative corrected mortality rates in various treatments reached 100%. After the 4th instar larvae were inoculated with B. bassiana spore suspension at the concentrations of 1×107, 1×108 and 1×109 conidia/mL, the duration before death was the shortest. Similarly, at 15 d post inoculation, the corrected infection rates of the 4th instar larvae exposed to 0 (CK), 1×105, 1×106, 1×107, 1×108 and 1×109 conidia/mL B. bassiana spore suspension were 0, 20.00%, 86.67%, 90.00%, 96.67% and 100.00%, respectively, showing that the higher concentration of B. bassiana spore suspension, the higher infection rate of M. alternatus larvae. Furthermore, the test results of the effects of 1×109 conidia/mL B. bassiana spore suspension on M. alternatus larvae in different body size showed that the larger the larvae, the higher their mortality and infection rate. At 20 d post inoculation with 1×109 conidia/mL B. bassiana spore suspension, the mortality rates of M. alternatus larvae with the body size of 100-150, 200-220, 300-320, 400-420, 500-520 and 600-650 mg/individual were 76.67%, 76.67%, 66.67%, 93.33%, 100.00% and 100.00%, respectively, and the infection rates were 60.00%, 63.33%, 60.00%, 86.67%, 96.67% and 100.00%, respectively. 【Conclusion】 The concentration of B. bassiana spore suspension has significant effects on the mortality and infection rate of M. alternatus larvae, both of which increase with the increasing of spore concentration. Furthermore, the larger the larvae of M. alternatus, the higher their mortality and infection rate by B. bassiana. Our results provide new clues for the management of M. alternatus by using B. bassiana.

Key words: Beauveria bassiana, Monochamus alternatus; spore suspension, body size, pathogenicity, bacterial infection rate, biological control