1株桉大毛虫病原真菌的分离鉴定及其寄主范围测定

Isolation and identification of pathogenic fungus from a strain of Suana divisa and determination of range of its hosts

  • 摘要: 【目的】明确1株从桉大毛虫上分离得到的虫生真菌的分类地位和生防潜力,为丰富虫生真菌资源及桉树林害虫的生物防治提供理论依据。【方法】采用常规组织分离法从自然感染死亡的桉大毛虫上分离病原菌,经致病性鉴定后,通过菌株形态学特征观察及rDNA-ITS、 EF1-αβ-tublin基因序列联合构建系统发育进化树确定病原菌的分类地位;以不同环境条件下菌丝生长与产孢量为指标测定病原菌的生物学特性;用病原菌孢子液喷洒供试虫体测定其寄主范围;将病原菌孢子配制成不同浓度梯度的孢子悬浮液处理东亚飞蝗、红火蚁和马尾松毛虫进行毒力测定;使用病原菌生产的菌粉进行大田防治试验,调查防治效果。【结果】从罹病桉大毛虫上分离到1株虫生真菌菌株DMC01,经致病性鉴定确定其为桉大毛虫致死病原菌;经形态学特性分析和分子鉴定确定菌株DMC01为爪哇棒束孢(Isariajavanica),全光照 (24 L∶0 D)、温度26 ℃、 pH 7、碳源为蔗糖、氮源为牛肉膏和酵母浸粉条件下最有利于其菌丝生长和产孢;菌株DMC01寄主范围初步测定其可寄生5目15种害虫,在1×108孢子/mL处理6~10 d后, 4龄东亚飞蝗、红火蚁和4龄马尾松毛虫的校正死亡率均达100.00%。2020年菌株DMC01菌粉对桉树林所有害虫的平均防效为51.9%,2021年平均防效达79.1%。【结论】从自然感染死亡的桉大毛虫上分离获得1株爪哇棒束孢菌株DMC01,该菌株对桉树林害虫具有高致病力,具有作为生防菌剂的潜力。

     

    Abstract: 【Objective】To clarify the taxonomy and biocontrol potential of an entomogenous fungal strain isolated from Suana divisa(Moore),so as to provide theoretical basis for enriching entomogenous fungal resources and biological prevention and control.【Method】 Pathogens were isolated and purified from a diseased S.divisa(Moore)by regular tissue isolation method.After pathogenicity identification,taxonomy of the pathogen was identified through morphological observation and constructing phylogenetic tree based on rDNA-ITS,EF1-α and β-tublin gene sequences.Biological characteristics of the fungi were determined by mycelial growth and spore production under different environmental conditions.The host range of the fungi was determined by spraying the tested insects with the pathogen spore solution.The spores of the fungi were prepared into spore suspension with different concentration gradients to treat Locusta migratoria manilensis (Meyen),Dendrolimus punctatus(Walker)and Solenopsis invicta(Buren).The field control experiment was carried out with powder produced by the fungi to investigate the control effect.【Result】 An entomogenous fungus strain DMC01 was isolated from S.divisa(Moore).The results of pathogenicity test showed that strain DMC01 was disease pathogenic fungus of S.divisa(Moore),and it was identified as Isaria javanica through morphological characteristics analysis and molecular identification.Full light,temperature of 26℃,pH of 7,sucrose as carbon source and yeast extract and beefextract as nitrogen sources were the most suitable for strain DMC01 mycelial growth and spore production.The preliminary determination of host range of strain DMC01 showed that it could parasitize 15 species of pests in 5 orders and under the treatment of 1×108 conidia/mL,the calibrated mortality of the 4th instar larvae of L.migratoria manilensis(Meyen),D.punctatus(Walker)and S.invicta(Buren)reached 100.00%.The results of field control experiment showed that the average control effectiveness of DMC01 strain powder on all pests insects on eucalyptus forest was 51.9% in 2020 and 79.1% in 2021.【Conclusion】 I.javanica strain DMC01 isolated from a naturally dead S.divisa(Moore)has high pathogenicity to eucalyptus forest pests and is potential to be a biocontrol agent.

     

/

返回文章
返回